CMC · California Mechanical Code
Where can condensate discharge and when are drainage pans required?
Homeowner summary: Condensate (water from your air‑conditioner or water heater) can’t just drip into the attic or out on the sidewalk — it must be collected and drained to an approved place, usually through an air‑gap into a sink, drywell, or approved receptor. If a water heater sits in an attic (or a leak would cause damage) the code requires a corrosion‑resistant pan beneath it with a visible 3/4" drain and a minimum 1.5" depth. Likewise, HVAC condensate drains must be sized, trapped, and sometimes have overflow pans or sensors so leaks don’t cause damage; these rules are in **§ 310.4**, **§ 310.5**, and **§ 305.5** of the California Mechanical Code.
Last reviewed: July 6, 2026
What the code requires — 2-4 sentences
Condensate from HVAC equipment must be collected and discharged to an approved plumbing fixture or disposal area and, when routed to the drainage system, must be via an indirect waste (air gap/air break) and sized/installed per the Mechanical Code. Key requirements for where condensate may discharge and how overflow protection must be provided are in § 310.4, § 310.5, and § 305.5 of the California Mechanical Code.
The single most important rule: collect condensate and route it to an approved disposal point — use an indirect connection (air gap/air break) and provide overflow protection (trap, pan, or alarm) when a leak or overflow can cause damage.
Requirements in detail
Where condensate may discharge (plain-English)
Condensate must be discharged to an approved plumbing fixture or disposal area. If it goes into the building drainage system it must go through an indirect waste (air gap/air break) to a trapped and vented receptor (mop sink, dry well, leach pit, or the tailpiece of a plumbing fixture), or other approved receptor. § 310.1 and § 310.5 control these points of discharge.
An individual condensate drain must be trapped either per the appliance manufacturer or as required in § 310.4.
When a drainage pan is required (water heaters and overflow protection)
A watertight pan of corrosion‑resistant material is required beneath a water heater located in an attic, within an attic ceiling assembly, floor‑ceiling assembly, floor‑subfloor assembly, or whenever a leaking water heater would cause damage; the pan must meet the dimensional and drain requirements of § 305.5.
For HVAC coils, condensing appliances, and equipment installed where condensate overflow can cause damage, the code requires an additional protection method — options include a water‑level detecting device, an additional watertight pan with a separate drain, an additional separate drain line at a higher level than the primary drain, or a watertight pan with detection + shutoff. See § 310.2.
Sizing, materials, slope and drain details (decision-relevant numbers)
| Decision item | Value / threshold | Code Reference |
|---|---|---|
| Minimum pan drain diameter (pan under water heater or auxiliary pan) | 3/4 inch (20 mm) nominal | § 305.5(1) and § 310.2 |
| Minimum pan depth (water heater pan) | 1 1/2 inches (38 mm) | § 305.5(2) |
| Condensate waste pipe slope | Not less than 1/8 inch per foot (1%) | § 310.1 |
| Minimum condensate pipe sizes by equipment capacity | See Table 310.3 (e.g., Up to 20 ton = 3/4", 21–40 ton = 1", 41–90 ton = 1-1/4" ) | § 310.3 (Table 310.3) |
| Connection to drainage system | Indirect (air gap/air break) to trapped and vented receptor | § 310.5 |
| Multiple appliances to common indirect waste | Connections must be protected by ASME A112.18.8 sanitary waste valve, IAPMO IGC 196 condensate trap, or trap + primer | § 310.4 |
Notes: materials must be corrosion‑resistant and appropriate for the liquid temperature; larger condensate drains (≥1-1/4") must be of plumbing-code materials.
Appliance condensate drains (what § 310.4 requires)
- Condensate drain lines from individual condensing appliances must follow the manufacturer’s sizing instructions. When multiple appliances drain into a common indirect waste, the connection must be protected by one of the listed devices (sanitary waste valve, condensate trap per IAPMO IGC 196, or trap with primer). § 310.4 is the controlling section.
Point of discharge (what § 310.5 requires)
- Condensate waste pipes must connect indirectly (air gap/air break) to receptors such as trapped and vented receptacles, dry wells, mop sinks, leach pits, or the tailpiece of plumbing fixtures. An individual condensate drain must be trapped per the appliance instructions or § 310.4.
Exceptions & special cases
Direct (plumbed) discharge into a lavatory tailpiece or tub overflow inlet is allowed for air‑conditioning coils only when the connection is in the area controlled by the same person controlling the air‑conditioned space (see § 310.6).
Condensate pumps are permitted where approved by the Authority Having Jurisdiction; pump discharge must rise to a point where gravity connection to a drain is possible, and each condensing unit must have a separate sump and be interlocked to prevent operation on sump failure unless approved otherwise (see § 310.1.1).
Discharge from a pressure‑relief valve into a drainage pan is prohibited — do not route a pressure‑relief outlet into a pan under a water heater. § 305.5(4).
Common mistakes
Assuming any visible roof or yard spot is an “approved disposal area.” The code requires an indirect connection or other approved receptor; condensate shall not drain over a public way. § 310.1 / § 310.5.
Installing a pan drain smaller than 3/4" or routing the pan drain to a concealed location; the terminating end must be readily visible. § 305.5(1).
Combining condensate drains from multiple appliances into a single indirect drain without the required sanitary waste valve / condensate trap / primer protection. § 310.4.
Allowing a relief valve to discharge into a pan or into the building interior. § 305.5(4) prohibits relief valve discharge into the pan.
Worked example — concrete scenario with numbers
Scenario: An attic‑mounted tank water heater serves a house. You must install a pan and route condensate/drainage per the CMC.
Because the water heater is located in an attic, install a watertight pan of corrosion‑resistant material under the heater — required by § 305.5.
Provide a pan drain of at least 3/4 inch nominal diameter that terminates at a visible exterior location (e.g., roof eave with visible outlet). § 305.5(1).
Make the pan at least 1-1/2 inches (38 mm) deep. § 305.5(2).
Do NOT route the water‑heater relief valve into the pan; relief valve discharge to the pan is prohibited. § 305.5(4).
Alternate example (HVAC air handler coil): An air handler coil with a capacity in the 30‑ton range:
Table 310.3 shows 21–40 ton → minimum condensate pipe = 1 inch. Use at least 1" condensate piping, with a slope of 1/8 inch per foot minimum. § 310.3 and § 310.1.
If the air handler is in a conditioned space where overflow would cause damage (e.g., over finished ceiling), provide an auxiliary watertight pan with a separate 3/4" drain or a water‑level sensor that shuts the unit off as permitted by § 310.2.
Related provisions
- § 310.1 — Condensate disposal: indirect waste, slope, material requirements.
- § 310.2 — Condensate control: overflow protection options (water‑level devices, pans, additional drain).
- § 310.3 — Condensate waste pipe material and sizing (Table 310.3).
- § 310.4 — Appliance condensate drains: sizing per manufacturer; protection for multiple appliances.
- § 310.5 — Point of discharge: indirect connections (air gap/air break) and trapping.
- § 310.6 — Special allowance for direct connection to lavatory/tub overflow when in same control area.
- § 305.5 — Drainage pan requirements for water heaters in attics/assemblies and related restrictions.
Code references
Grounded in the retrieved California Mechanical Code — click a citation to read the verbatim passage:
CMC § 307.4 High relevance — show source text
(11)Required clearances from combustible surfaces on which or adjacent to which it is permitted to be mounted.
An appliance shall be accompanied by clear and complete installation instructions, including required clearances from combustible other than mounting or adjacent surfaces, and temperature rating of field-installed wiring connections exceeding 140°F (60°C). 307.4 Absorption Units. Absorption units shall bear a permanent and legible factory-applied nameplate on which shall
appear:
(1) The name or trademark of the manufacturer.
(2) The model number or equivalent.
(3) The serial number.
(4) The amount of refrigerant.
(5) The refrigerant designation.
(6) Hourly rating in Btu/h (kW).
(7) The type of fuel approved for use with the unit.
(8) Cooling capacity Btu/h (kW).
(9) Required clearances from combustible surfaces on which or adjacent to which it is permitted to be mounted.
(10)The symbol of an approved agency certifying compliance of the equipment with recognized standards.
56 2025 CALIFORNIA MECHANICAL CODE
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GENERAL REGULATIONS
308.0 Improper Location.
308.1 General. Piping or equipment shall not be so located as to interfere with the normal use thereof or with the normal operation and use of windows, doors, or other required facilities.
309.0 Workmanship.
309.1 Engineering Practices. Design, construction, and workmanship shall comply with accepted engineering practices and shall be of such character as to secure the results sought to be obtained by this code.
309.2 Concealing Imperfections. It shall be unlawful to conceal cracks, holes, or other imperfections in materials by welding, brazing, or soldering, by using therein or thereon paint, wax, tar, solvent cement, other leak-sealing or repair agent.
309.3 Installation Practices. Mechanical systems shall be installed in a manner that is in accordance with this code, applicable standards, and the manufacturer’s installation instructions. All mechanical systems shall be in accordance with construction documents approved by the Authority Having Jurisdiction.
310.0 Condensate Wastes and Control.
310.1 Condensate Disposal. Condensate from air washers, air-cooling coils, condensing appliances, and the overflow from evaporative coolers and similar water-supplied equipment or similar air-conditioning equipment shall be collected and discharged to an approved plumbing fixture or disposal area. Where discharged into the drainage system, equipment shall drain by means of an indirect waste pipe. The waste pipe shall have a slope of not less than [1] ⁄ 8 inch per foot (10.4 mm/m) or 1 percent slope and shall be of approved corrosion-resistant material not smaller than the outlet size in
accordance with Section 310.3 or Section 310.4 for air-cooling coils or condensing appliances, respectively. Condensate or wastewater shall not drain over a public way.
CMC § 309.0 Medium relevance — show source text
309.0 Workmanship.
309.1 Engineering Practices. Design, construction, and workmanship shall comply with accepted engineering practices and shall be of such character as to secure the results sought to be obtained by this code.
309.2 Concealing Imperfections. It shall be unlawful to conceal cracks, holes, or other imperfections in materials by welding, brazing, or soldering, by using therein or thereon paint, wax, tar, solvent cement, other leak-sealing or repair agent.
309.3 Installation Practices. Mechanical systems shall be installed in a manner that is in accordance with this code, applicable standards, and the manufacturer’s installation instructions. All mechanical systems shall be in accordance with construction documents approved by the Authority Having Jurisdiction.
310.0 Condensate Wastes and Control.
310.1 Condensate Disposal. Condensate from air washers, air-cooling coils, condensing appliances, and the overflow from evaporative coolers and similar water-supplied equipment or similar air-conditioning equipment shall be collected and discharged to an approved plumbing fixture or disposal area. Where discharged into the drainage system, equipment shall drain by means of an indirect waste pipe. The waste pipe shall have a slope of not less than [1] ⁄ 8 inch per foot (10.4 mm/m) or 1 percent slope and shall be of approved corrosion-resistant material not smaller than the outlet size in
accordance with Section 310.3 or Section 310.4 for air-cooling coils or condensing appliances, respectively. Condensate or wastewater shall not drain over a public way.
310.1.1 Condensate Pumps. Where approved by the Authority Having Jurisdiction, condensate pumps shall be installed in accordance with the manufacturer’s installation instructions. Pump discharge shall rise vertically to a point where it is possible to connect to a gravity condensate drain and discharged to an approved disposal point. Each condensing unit shall be provided with a separate sump and interlocked with the equipment to prevent the equipment from operating during a failure. Separate pumps shall be permitted to connect to a single gravity indirect waste where equipped with check valves and approved by the Authority Having Jurisdiction.
310.2 Condensate Control. Where any equipment or appliance is installed in a space where damage is capable of resulting from condensate overflow, a drain line shall be provided and shall be drained in accordance with Section 310.1. An additional protection method for condensate overflow shall be provided in accordance with one of the following:
(1) A water level detecting device that will shut off the equipment or appliance in the event the primary drain is
EQUIPMENT CAPACITY IN
TONS OF REFRIGERATIONMINIMUM CONDENSATE
PIPE DIAMETER
(inches)
Up to 203⁄4
21 – 401
41 – 9011⁄4
91 – 12511⁄2
126 – 2502 For SI units: 1 ton of refrigeration = 3.52 kW, 1 inch = 25 mm
CMC § 10.4 Medium relevance — show source text
The size of condensate waste pipes is for one unit or a combination of units, or as recommended by the manufacturer. The capacity of waste pipes assumes a [1] ⁄ 8 inch per foot (10.4 mm/m) or 1 percent slope, with the pipe running threequarters full at the following pipe conditions:
Outside Air – 20% Col2 Room Air – 80% Col4 DB WB DB WB 90°F 73°F 75°F 62.5°F For SI units: °C = (°F-32)/1.8
blocked. Such detecting device shall be in accordance with the manufacturer’s installation instructions.
(2) An additional watertight pan of corrosion-resistant material, with a separate drain line, installed beneath the cooling coil, unit, or the appliance to catch the overflow condensate due to a clogged primary condensate drain.
(3) An additional separate drain line at a level that is higher than the primary drain line connection of the drain pan.
(4) An additional watertight pan of corrosion-resistant material with a water level detection device installed beneath
the cooling coil, unit, or the appliance to catch the overflow condensate due to a clogged primary condensate drain and to shut off the equipment.
The additional pan or the additional drain line connection shall be provided with a drain pipe of not less than [3] ⁄ 4 of an inch (20 mm) nominal pipe size, discharging at a point that is readily observed.
310.2.1 Protection of Appurtenances. Where insulation or appurtenances are installed where damage is capable of resulting from a condensate drain pan overfill, such installations shall occur above the rim of the drain
pan with supports. Where the supports are in contact with the condensate waste, the supports shall be of approved corrosion-resistant material.
310.3 Condensate Waste Pipe Material and Sizing. Condensate waste pipes from air-cooling coils shall be sized in accordance with the equipment capacity as specified in Table 310.3. The material of the piping shall comply with the pressure and temperature rating of the appliance or equipment, and shall be approved for use with the liquid being discharged.
TABLE 310.3
MINIMUM CONDENSATE PIPE SIZE
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GENERAL REGULATIONS
Condensate drain sizing for other slopes or other conditions shall be approved by the Authority Having Jurisdiction.
Air-conditioning waste pipes, 1¼ of an inch (32 mm) and larger in size, shall be constructed of materials specified in the plumbing code. Condensate waste piping less than 1¼ of an inch (32 mm) in size shall be permitted to be PVC, CPVC, PE, PP, copper, or other rigid materials approved by the Authority Having Jurisdiction.
310.3.1 Cleanouts. Condensate drain lines shall be configured or provided with a cleanout to permit the clearing of blockages and for maintenance without requiring the drain line to be cut.
CMC § 2.3. Medium relevance — show source text
The reserved pathway and penetrations through the building envelope shall be sized to meet one of the following: i. The reserved pathway and penetrations shall be sized to serve a HPWH system that meets the total building hot water demand as calculated and documented by the responsible person associated with the project. ii. The reserved pathway and penetrations shall be sized to meet the requirements specified in Joint Appendix JA15.2.3.
Condensate drainage piping. An approved receptacle that is sized per the California Plumbing Code for condensate drainage shall be installed within 3 feet of the reserved heat pump location, or piping shall be installed from within 3 feet of the reserved heat pump location to an approved discharge location that is sized in accordance with the California Plumbing Code, and meet one of the following: i. Condensate drainage shall be sized to serve a HPWH system that meets the total building hot water demand as calculated and documented by the responsible person associated with the project. ii. Condensate drainage piping shall be sized to meet the requirements specified in Joint Appendix JA15.2.4.
Electrical.
A. Physical space shall be reserved on the bus system of the main switchboard or on the bus system of a distribution board to serve the future HPWH system, including the heat pump and temperature maintenance tanks. In addition, the physical space reserved shall be capable of providing adequate power to the future heat pump water heater in accordance with the following: i. Heat pump. Meet one of the following: A. The electrical power required to power a HPWH system that meets the total building hot water demand as calculated and documented by the responsible person associated with the project. B. The electrical power required that meets the requirements specified for the heat pump in Joint Appendix JA15.2.5.
ii. Temperature maintenance tank. Meet one of the following: A. The electrical power required to power a HPWH system temperature maintenance tank that meets the total building hot water demand as calculated and documented by the responsible person associated with the project. B. The electrical power required that meets the requirements specified for the temperature maintenance tank in Joint Appendix JA15.2.5.
NOTE: Authority: Sections 25213, 25218, 25218.5, 25402 and 25402.1, Public Resources Code . Reference: Sections 25007, 25008, 25218.5 25310, 25402, 25402.1, 25402.4, 25402.5, 25402.8 and 25943, Public Resources Code .
236 2025 CALIFORNIA ENERGY CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
11 MULTIFAMILY BUILDINGS—PERFORMANCE
AND PRESCRIPTIVE COMPLIANCE APPROACHES
SECTION 170.0—GENERAL
Multifamily buildings shall comply with the applicable requirements of Sections 170.0 through 170.2. Sections 170.0 through 170.2 apply to dwelling units and common use areas in multifamily buildings. Nonresidential occupancies in mixed occupancy buildings shall comply with nonresidential requirements in Sections 120, 130, 140 and 141.
CMC § 814.0 Medium relevance — show source text
814.0 Condensate Waste and Control.
814.1 Condensate Disposal. Condensate from air washers, air-cooling coils, condensing appliances, and the over
2025 CALIFORNIA PLUMBING CODE 183
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INDIRECT WASTES
flow from evaporative coolers and similar water-supplied equipment or similar air-conditioning equipment shall be collected and discharged to an approved plumbing fixture or disposal area. Where discharged into the drainage system, equipment shall drain using an indirect waste pipe. The waste pipe shall have a slope of not less than [1] ⁄ 8 inch per foot (10.4 mm/m) or 1 percent slope and shall be of an approved corrosion-resistant material not smaller than the outlet size in
accordance with Section 814.3 or Section 814.4 for air-cooling coils or condensing appliances, respectively. Condensate or wastewater shall not drain over a public way.
814.1.1 Condensate Pumps. Where approved by the Authority Having Jurisdiction, condensate pumps shall be installed in accordance with the manufacturer’s instal lation instructions. Pump discharge shall rise vertically to a point where it is possible to connect to a gravity condensate drain and discharged to an approved disposal point. Each condensing unit shall be provided with a separate sump and interlocked with the equipment to prevent the equipment from operating during a failure. Separate pumps shall be permitted to connect to a single gravity indirect waste where equipped with check valves and approved by the Authority Having Jurisdiction.
814.2 Condensate Control. Where any equipment or appliance is installed in a space where damage is capable of resulting from condensate overflow, a drain line shall be provided and shall be drained in accordance with Section 814.1.
An additional protection method for condensate overflow shall be provided in accordance with one of the following:
(1) A water level detecting device that will shut off the equipment or appliance in the event the primary drain is blocked. Such detecting device shall be in accordance with the manufacturer’s installation instructions.
(2) An additional watertight pan of corrosion-resistant material, with a separate drain line, installed beneath the cooling coil, unit, or the appliance to catch the overflow condensate due to a clogged primary condensate drain.
(3) An additional separate drain line at a level that is higher than the primary drain line connection of the drain pan.
(4) An additional watertight pan of corrosion-resistant material with a water level detection device installed beneath
the cooling coil, unit, or the appliance to catch the overflow condensate due to a clogged primary condensate drain and to shut off the equipment.
The additional pan or the additional drain line connection shall be provided with a drainpipe of not less than [3] ⁄ 4 of an inch (20 mm) nominal pipe size, discharging at a point that is readily observed.
814.2.1 Protection of Appurtenances. Where insulation or appurtenances are installed where damage is capable of resulting from a condensate drain pan overfill, such installations shall occur above the rim of the drain
pan with supports. Where the supports are in contact with the condensate waste, the supports shall be of approved corrosion-resistant material.
CMC § 310.5 Medium relevance — show source text
310.5 Point of Discharge. Air-conditioning condensate waste pipes shall connect indirectly to the drainage system through an air gap or air break to trapped and vented receptors, dry wells, mop sinks, leach pits, or the tailpiece of plumbing fixtures. An individual condensate drain shall be trapped in accordance with the appliance manufacturer’s instructions or in accordance with Section 310.4.
310.6 Condensate Waste from Air-Conditioning Coils. Where the condensate waste from air-conditioning coils discharges by direct connection to a lavatory tailpiece or to an approved accessible inlet on a bathtub overflow, the connection shall be located in the area controlled by the same person controlling the air-conditioned space. 310.7 Female Plastic Connections. Female plastic screwed fittings shall be used with plastic male fittings and plastic male threads. Female plastic threaded connections shall not be allowed to be used when threaded onto a male
metallic connection.
311.0 Heating or Cooling Air System. 311.1 Source. A heating or cooling air system shall be provided with return air, outside air, or both. A heating or cooling air system regulated by this code and designed to replace required ventilation shall be arranged to discharge into a conditioned space not less than the amount of outside air specified in Chapter 4.
311.2 Air Filters. Air filters shall be installed in a heating, cooling, or makeup air system. Media-type air filters shall comply with UL 900. Electrostatic and high efficiency particulate filters shall comply with Section 935.0.
Exceptions:
(1) Air filters used in systems serving single guest rooms or dwelling units shall not be required to be listed.
(2) Air filters used in listed appliances and in accordance with the manufacturer’s instructions.
311.2.1 Minimum Filtration. In mechanically ventilated buildings, occupied areas of the building shall be provided with air filtration media for outside and return air that provides not less than a Minimum Efficiency Reporting Value (MERV) of 13 or as required by the Authority Having Jurisdiction. Installed filters shall be clearly labeled by the manufacturer indicating the MERV rating.
311.3 Prohibited Sources. Outside or return air for a heating or cooling air system shall not be taken from the following locations:
(1) Less than the separation distances to vents required by Section 802.6.1 and Section 802.8.
(2) Less than the separation distances required by Section 402.4.
(3) A hazardous or insanitary location, or a refrigeration machinery room as defined in this code.
(4) An area, the volume of which is less than 25 percent of the entire volume served by such system, unless there is a permanent opening to an area the volume of which is equal to 25 percent of the entire volume served.
Exception: Such openings where used for a heating or cooling air system in a dwelling unit shall be permitted to be reduced to not less than 50 percent of the required area, provided the balance of the required return air is taken from a room or hall having not less than three doors leading to other rooms served by the furnace.
(5) A closet, bathroom, toilet room, kitchen, garage, boiler room, furnace room, or unconditioned attic.
(6) Rooms or spaces containing a fuel-burning appliance therein. Where such room or space serves as source of return-air.
Exceptions:
CMC § 310.1.1 Medium relevance — show source text
310.1.1 Condensate Pumps. Where approved by the Authority Having Jurisdiction, condensate pumps shall be installed in accordance with the manufacturer’s installation instructions. Pump discharge shall rise vertically to a point where it is possible to connect to a gravity condensate drain and discharged to an approved disposal point. Each condensing unit shall be provided with a separate sump and interlocked with the equipment to prevent the equipment from operating during a failure. Separate pumps shall be permitted to connect to a single gravity indirect waste where equipped with check valves and approved by the Authority Having Jurisdiction.
310.2 Condensate Control. Where any equipment or appliance is installed in a space where damage is capable of resulting from condensate overflow, a drain line shall be provided and shall be drained in accordance with Section 310.1. An additional protection method for condensate overflow shall be provided in accordance with one of the following:
(1) A water level detecting device that will shut off the equipment or appliance in the event the primary drain is
EQUIPMENT CAPACITY IN
TONS OF REFRIGERATIONMINIMUM CONDENSATE
PIPE DIAMETER
(inches)
Up to 203⁄4
21 – 401
41 – 9011⁄4
91 – 12511⁄2
126 – 2502 For SI units: 1 ton of refrigeration = 3.52 kW, 1 inch = 25 mm
The size of condensate waste pipes is for one unit or a combination of units, or as recommended by the manufacturer. The capacity of waste pipes assumes a [1] ⁄ 8 inch per foot (10.4 mm/m) or 1 percent slope, with the pipe running threequarters full at the following pipe conditions:
Outside Air – 20% Col2 Room Air – 80% Col4 DB WB DB WB 90°F 73°F 75°F 62.5°F For SI units: °C = (°F-32)/1.8
blocked. Such detecting device shall be in accordance with the manufacturer’s installation instructions.
(2) An additional watertight pan of corrosion-resistant material, with a separate drain line, installed beneath the cooling coil, unit, or the appliance to catch the overflow condensate due to a clogged primary condensate drain.
(3) An additional separate drain line at a level that is higher than the primary drain line connection of the drain pan.
(4) An additional watertight pan of corrosion-resistant material with a water level detection device installed beneath
the cooling coil, unit, or the appliance to catch the overflow condensate due to a clogged primary condensate drain and to shut off the equipment.
The additional pan or the additional drain line connection shall be provided with a drain pipe of not less than [3] ⁄ 4 of an inch (20 mm) nominal pipe size, discharging at a point that is readily observed.
310.2.1 Protection of Appurtenances. Where insulation or appurtenances are installed where damage is capable of resulting from a condensate drain pan overfill, such installations shall occur above the rim of the drain
CMC § 814.2 Medium relevance — show source text
814.2 Condensate Control. Where any equipment or appliance is installed in a space where damage is capable of resulting from condensate overflow, a drain line shall be provided and shall be drained in accordance with Section 814.1.
An additional protection method for condensate overflow shall be provided in accordance with one of the following:
(1) A water level detecting device that will shut off the equipment or appliance in the event the primary drain is blocked. Such detecting device shall be in accordance with the manufacturer’s installation instructions.
(2) An additional watertight pan of corrosion-resistant material, with a separate drain line, installed beneath the cooling coil, unit, or the appliance to catch the overflow condensate due to a clogged primary condensate drain.
(3) An additional separate drain line at a level that is higher than the primary drain line connection of the drain pan.
(4) An additional watertight pan of corrosion-resistant material with a water level detection device installed beneath
the cooling coil, unit, or the appliance to catch the overflow condensate due to a clogged primary condensate drain and to shut off the equipment.
The additional pan or the additional drain line connection shall be provided with a drainpipe of not less than [3] ⁄ 4 of an inch (20 mm) nominal pipe size, discharging at a point that is readily observed.
814.2.1 Protection of Appurtenances. Where insulation or appurtenances are installed where damage is capable of resulting from a condensate drain pan overfill, such installations shall occur above the rim of the drain
pan with supports. Where the supports are in contact with the condensate waste, the supports shall be of approved corrosion-resistant material.
814.3 Condensate Waste Pipe Material and Sizing. Condensate waste pipes from air-cooling coils shall be sized in accordance with the equipment capacity as specified in Table 814.3. The material of the piping shall comply with the pressure and temperature rating of the appliance or equipment and shall be approved for use with the liquid being discharged.
TABLE 814.3
MINIMUM CONDENSATE PIPE SIZE
EQUIPMENT CAPACITY IN TONS
OF REFRIGERATIONMINIMUM CONDENSATE PIPE
DIAMETER
(inches)Up to 20 3⁄4
21 – 401
41 – 9011⁄4
91 – 12511⁄2
126 – 2502 For SI units: 1 ton of refrigerant = 3.52 kW, 1 inch = 25 mm
The size of condensate waste pipes is for one unit or a combination of units, or as recommended by the manufacturer. The capacity of waste pipes assumes a [1] ⁄ 8 inch per foot (10.4 mm/m) or 1 percent slope, with the pipe running threequarters full at the following pipe conditions:
Outside Air – 20% Col2 Room Air – 80% Col4
DBWB DB WB
90°F73°F 75°F 62.5°FFor SI units: °C = (°F-32)/1.8
CMC § 305.6 Medium relevance — show source text
305.6 Outdoor Locations . . . . . . . . . . . . . 55
306.0 Automatic Control Devices . . . . . . . 55
306.1 General. . . . . . . . . . . . . . . . . . . . . . 55
306.2 Building Automation Systems . . . . 56
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TABLE OF CONTENTS
307.0 Labeling . . . . . . . . . . . . . . . . . . . . . 56
307.1 Fuel-Burning Appliances . . . . . . . . 56
307.2 Electric Heating Appliances . . . . . . 56
307.3 Heat Pump and Electric Cooling Appliances . . . . . . . . . . . . . . . . . . . 56
307.4 Absorption Units . . . . . . . . . . . . . . . 56
308.0 Improper Location. . . . . . . . . . . . . . 57
308.1 General. . . . . . . . . . . . . . . . . . . . . . 57
309.0 Workmanship . . . . . . . . . . . . . . . . . 57
309.1 Engineering Practices. . . . . . . . . . . 57
309.2 Concealing Imperfections . . . . . . . . 57
309.3 Installation Practices. . . . . . . . . . . . 57
310.0 Condensate Wastes and Control . . 57
310.1 Condensate Disposal . . . . . . . . . . . 57
310.2 Condensate Control . . . . . . . . . . . . 57
310.3 Condensate Waste Pipe Material and Sizing. . . . . . . . . . . . . . . . . . . . 57
Table 310.3 Minimum Condensate Pipe Size. . . 57
310.4 Appliance Condensate Drains . . . . 58
310.5 Point of Discharge . . . . . . . . . . . . . 58
310.6 Condensate Waste from
Air-Conditioning Coils . . . . . . . . . . . 58
310.7 Female Plastic Connections . . . . . . 58
311.0 Heating or Cooling Air System . . . . 58
311.1 Source . . . . . . . . . . . . . . . . . . . . . . 58
311.2 Air Filters . . . . . . . . . . . . . . . . . . . . 58
311.3 Prohibited Sources . . . . . . . . . . . . . 58
311.4 Return-Air Limitations . . . . . . . . . . . 58
311.5 California Energy Code Requirements for Residential
Air Filtration . . . . . . . . . . . . . . . . . . 59
312.0 Plumbing Connections . . . . . . . . . . 59
312.1 General. . . . . . . . . . . . . . . . . . . . . . 59
CMC § 310.1 Medium relevance — show source text
310.1 Condensate Disposal . . . . . . . . . . . 57
310.2 Condensate Control . . . . . . . . . . . . 57
310.3 Condensate Waste Pipe Material and Sizing. . . . . . . . . . . . . . . . . . . . 57
Table 310.3 Minimum Condensate Pipe Size. . . 57
310.4 Appliance Condensate Drains . . . . 58
310.5 Point of Discharge . . . . . . . . . . . . . 58
310.6 Condensate Waste from
Air-Conditioning Coils . . . . . . . . . . . 58
310.7 Female Plastic Connections . . . . . . 58
311.0 Heating or Cooling Air System . . . . 58
311.1 Source . . . . . . . . . . . . . . . . . . . . . . 58
311.2 Air Filters . . . . . . . . . . . . . . . . . . . . 58
311.3 Prohibited Sources . . . . . . . . . . . . . 58
311.4 Return-Air Limitations . . . . . . . . . . . 58
311.5 California Energy Code Requirements for Residential
Air Filtration . . . . . . . . . . . . . . . . . . 59
312.0 Plumbing Connections . . . . . . . . . . 59
312.1 General. . . . . . . . . . . . . . . . . . . . . . 59
313.0 Hangers, Supports, and Anchors . . 59
313.1 General. . . . . . . . . . . . . . . . . . . . . . 59
313.2 Material. . . . . . . . . . . . . . . . . . . . . . 59
313.3 Suspended Piping . . . . . . . . . . . . . 59
313.4 Alignment . . . . . . . . . . . . . . . . . . . . 59
313.5 Underground Installation . . . . . . . . 59
313.6 Hanger Rod Sizes . . . . . . . . . . . . . 59
Table 313.6 Hanger Rod Sizes . . . . . . . . . . . . . 59
313.7 Gas Piping . . . . . . . . . . . . . . . . . . . 59
314.0 Balancing . . . . . . . . . . . . . . . . . . . . 59
314.1 General. . . . . . . . . . . . . . . . . . . . . . 59
315.0 Louvers in Hurricane Prone
Regions . . . . . . . . . . . . . . . . . . . . . 59
315.1 General. . . . . . . . . . . . . . . . . . . . . . 59
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316.0 Protection of Piping, Tubing, Materials, and Structures . . . . . . . . 59
316.1 General. . . . . . . . . . . . . . . . . . . . . . 59
CMC § 1001.4. Medium relevance — show source text
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shall drain by indirect waste in accordance with Section 1001.4. Embedded piping underground or under floors is not required to be designed for draining the system.
1221.5 Condensate Drainage. Condensate drains from dehumidifying coils shall be constructed and sloped for condensate removal. Such drains shall be installed in accordance
with Section 310.0.
1221.6 Hydronic Fluid Disposal. Hydronic system fluids that contain additives such as antifreeze, corrosion inhibitors, and cleaning solutions shall be recycled or disposed of in an approved manner in accordance with Environmental Protection Agency (EPA), the Department of Health, and as required by the Authority Having Jurisdiction.
1221.7 Clearance to Combustibles. Hydronic piping where the exterior temperature exceeds 250°F (121°C) shall have a clearance of not less 1 inch (25.4 mm) to combustible materials.
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CALIFORNIA MECHANICAL CODE – MATRIX ADOPTION TABLE
CHAPTER 13 – FUEL GAS PIPING
(Matrix Adoption Tables are non-regulatory, intended only as an aid to the code user. See Chapter 1 for state agency authority and building applications.)
Adopting Agency BSC BSC-
CGSFM HCD Col6 Col7 DSA Col9 Col10 OSHPD Col12 Col13 Col14 Col15 Col16 Col17 BSCC DPH AGR DWR CEC CA SL SLC Adopting Agency BSC BSC-
CGSFM 1 2 1-AC AC ** SS** ** SS/CC** 1 1R 2 3 4 5 6 6 6 6 6 6 6 6 6 Adopt Entire Chapter X X X X X X X X X X X X Adopt Entire Chapter as
amended (amended sections
listed below)Adopt only those sections
that are listed belowChapter/Section CMC § 1105.0 Medium relevance — show source text
1105.0 General Requirements.
1105.1 Human Comfort. Cooling systems used for human comfort shall be in accordance with the return-air and outside-air provisions for furnaces in Section 604.1 and Section 904.8. Cooling equipment used for human comfort in residential buildings shall be selected in accordance with ACCA Manual S to satisfy the calculated loads determined in accordance with ACCA Manual J or other approved methods. Refrigerants used for human comfort shall be in accordance with Section 1104.7.
1105.2 Supports and Anchorage. Supports and anchorage for refrigeration equipment and piping shall be designed in accordance with the building code as Occupancy Category H (hazardous facilities). Supports shall be made of noncombustible materials.
Exceptions:
(1) Equipment containing Group A1 refrigerants shall be permitted to be supported by the same materials permitted for the building type.
(2) The use of approved vibration isolators specifically designed for the normal, wind, and seismic loads encountered, shall be permitted.
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REFRIGERATION
than 2 square feet (0.2 m [2] ) net free area opening shall be terminated directly to the outside of the building or extend to the outside of the building by continuous ducts.
1105.5.2 Mechanical Exhaust System. A mechanical exhaust system shall be designed to provide a complete change of air not less than every 20 minutes in such room or space and shall discharge to the outside of the building.
Exceptions:
(1) A condensing unit in a room or space where the cubical content exceeds 1000 cubic feet per horsepower (ft [3] /hp) (37.95 m [3] /kW) of the unit.
(2) A condensing unit in a room or space that has permanent gravity ventilation having an area of 2 square feet (0.2 m [2] ) or more to other rooms or openings exceeding 1000 ft [3] /hp (37.95 m [3] /kW).
1105.6 Prohibited Locations. Refrigeration systems or portions thereof shall not be located within a required exit enclosure. Refrigeration compressors exceeding 5 horsepowers (3.7 kW) rating shall be located not less than 10 feet (3048 mm) from an exit opening in a Group A; Group B; Group E; Group F; Group I; Group R, Division 1; or Group S Occupancy, unless separated by a one-hour fire-resistive occupancy separation.
1105.7 Condensate. Condensate from air-cooling coils shall be collected and drained to an approved location. Drain pans and coils shall be arranged to allow thorough drainage and access for cleaning. Where temperatures drop below freezing, heat tracing and insulation of condensate drains shall be installed.
1105.8 Defrost. Where defrost cycles are required for portions of the system, provisions shall be made for collection and disposal of the defrost liquid in a safe and sanitary man ner.
1105.9 Overflows. Where condensate or defrost liquids are generated in an attic or furred space, and structural damage will result from overflow, provisions for overflow shall be provided.
CMC § 808.0 Medium relevance — show source text
808.0 Cooling Water . . . . . . . . . . . . . . . .182
808.1 General . . . . . . . . . . . . . . . . . . . . .182
809.0 Drinking Fountains . . . . . . . . . . . .182
809.1 General . . . . . . . . . . . . . . . . . . . . .182
810.0 Steam and Hot Water Drainage Condensers and Sumps . . . . . . . .182
810.1 High-Temperature Discharge . . . .182
Table 810.1 Pipe Connections in Blowoff Condensers and Sumps . . . . . . . .183
810.2 Sumps, Condensers, and Intercepting Tanks . . . . . . . . . . . .183
810.3 Cleaning . . . . . . . . . . . . . . . . . . . .183
810.4 Strainers . . . . . . . . . . . . . . . . . . . .183
811.0 Chemical Wastes . . . . . . . . . . . . .183
811.1 Pretreatment . . . . . . . . . . . . . . . . .183
811.2 Waste and Vent Pipes . . . . . . . . .183
811.3 Joining Materials . . . . . . . . . . . . . .183
811.4 Access . . . . . . . . . . . . . . . . . . . . .183
811.5 Permanent Record . . . . . . . . . . . .183
811.6 Chemical Vent . . . . . . . . . . . . . . .183
811.7 Discharge . . . . . . . . . . . . . . . . . . .183
811.8 Diluted Chemicals . . . . . . . . . . . . .183
812.0 Clear Water Wastes . . . . . . . . . . .183
812.1 General . . . . . . . . . . . . . . . . . . . . .183
813.0 Swimming Pools . . . . . . . . . . . . . .183
813.1 General . . . . . . . . . . . . . . . . . . . . .183
814.0 Condensate Waste and Control . . .183
814.1 Condensate Disposal . . . . . . . . . .183
814.2 Condensate Control . . . . . . . . . . .184
814.3 Condensate Waste Pipe Material and Sizing . . . . . . . . . . . .184
Table 814.3 Minimum Condensate Pipe Size . . . . . . . . . . . . . . . . . . .184
814.4 Appliance Condensate Drains . . .184
814.5 Point of Discharge . . . . . . . . . . . .184
814.6 Condensate Waste from
Air-Conditioning Coils . . . . . . . . . .185
814.7 Plastic Fittings . . . . . . . . . . . . . . .185
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TABLE OF CONTENTS
CMC § 811.3 Medium relevance — show source text
CPVC pipe and fittings shall comply with ASTM F2618. PP pipe and fittings shall comply with ASTM F1412 or CSA B181.3. PVDF pipe and fittings shall comply with ASTM F1673 or CSA B181.3. Chemical-resistant glass pipe and fittings shall comply with ASTM C1053. High-silicon iron pipe and fittings shall comply with ASTM A861.
811.3 Joining Materials. Joining materials shall be of approved type and quality.
811.4 Access. Where practicable, the piping shall be readily accessible and installed with the maximum of clearance from other services.
811.5 Permanent Record. The owner shall make and keep a permanent record of the location of piping and venting carrying chemical waste.
811.6 Chemical Vent. No chemical vent shall intersect
vents for other services.
811.7 Discharge. Chemical wastes shall be discharged in a manner approved by the Authority Having Jurisdiction.
811.8 Diluted Chemicals. The provisions of this section about materials and methods of construction shall not apply to installations such as photographic or x-ray darkrooms or research or control laboratories where minor amounts of ade quately diluted chemicals are discharged.
812.0 Clear Water Wastes.
812.1 General. Water lifts, expansion tanks, cooling jackets, sprinkler systems, drip or overflow pans, or similar devices that discharge clear wastewater into the building drainage system shall discharge through an indirect waste.
813.0 Swimming Pools.
813.1 General. Pipes carrying wastewater from swimming or wading pools, including pool drainage and backwash from filters, shall be installed as an indirect waste. Where a pump is used to discharge pool waste water to the drainage system, the pump discharge shall be installed as an indirect waste.
814.0 Condensate Waste and Control.
814.1 Condensate Disposal. Condensate from air washers, air-cooling coils, condensing appliances, and the over
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INDIRECT WASTES
flow from evaporative coolers and similar water-supplied equipment or similar air-conditioning equipment shall be collected and discharged to an approved plumbing fixture or disposal area. Where discharged into the drainage system, equipment shall drain using an indirect waste pipe. The waste pipe shall have a slope of not less than [1] ⁄ 8 inch per foot (10.4 mm/m) or 1 percent slope and shall be of an approved corrosion-resistant material not smaller than the outlet size in
accordance with Section 814.3 or Section 814.4 for air-cooling coils or condensing appliances, respectively. Condensate or wastewater shall not drain over a public way.
814.1.1 Condensate Pumps. Where approved by the Authority Having Jurisdiction, condensate pumps shall be installed in accordance with the manufacturer’s instal lation instructions. Pump discharge shall rise vertically to a point where it is possible to connect to a gravity condensate drain and discharged to an approved disposal point. Each condensing unit shall be provided with a separate sump and interlocked with the equipment to prevent the equipment from operating during a failure. Separate pumps shall be permitted to connect to a single gravity indirect waste where equipped with check valves and approved by the Authority Having Jurisdiction.
CMC § 310.2.1 Medium relevance — show source text
310.2.1 Protection of Appurtenances. Where insulation or appurtenances are installed where damage is capable of resulting from a condensate drain pan overfill, such installations shall occur above the rim of the drain
pan with supports. Where the supports are in contact with the condensate waste, the supports shall be of approved corrosion-resistant material.
310.3 Condensate Waste Pipe Material and Sizing. Condensate waste pipes from air-cooling coils shall be sized in accordance with the equipment capacity as specified in Table 310.3. The material of the piping shall comply with the pressure and temperature rating of the appliance or equipment, and shall be approved for use with the liquid being discharged.
TABLE 310.3
MINIMUM CONDENSATE PIPE SIZE
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GENERAL REGULATIONS
Condensate drain sizing for other slopes or other conditions shall be approved by the Authority Having Jurisdiction.
Air-conditioning waste pipes, 1¼ of an inch (32 mm) and larger in size, shall be constructed of materials specified in the plumbing code. Condensate waste piping less than 1¼ of an inch (32 mm) in size shall be permitted to be PVC, CPVC, PE, PP, copper, or other rigid materials approved by the Authority Having Jurisdiction.
310.3.1 Cleanouts. Condensate drain lines shall be configured or provided with a cleanout to permit the clearing of blockages and for maintenance without requiring the drain line to be cut.
310.4 Appliance Condensate Drains. Condensate drain lines from individual condensing appliances shall be sized as required by the manufacturer’s instructions. Condensate drain lines serving more than one appliance connecting to a common indirect waste pipe shall have the connections to the indirect waste pipe protected by a sanitary waste valve complying with ASME A112.18.8, condensate trap complying with IAPMO IGC 196, or trap with a trap primer.
310.5 Point of Discharge. Air-conditioning condensate waste pipes shall connect indirectly to the drainage system through an air gap or air break to trapped and vented receptors, dry wells, mop sinks, leach pits, or the tailpiece of plumbing fixtures. An individual condensate drain shall be trapped in accordance with the appliance manufacturer’s instructions or in accordance with Section 310.4.
310.6 Condensate Waste from Air-Conditioning Coils. Where the condensate waste from air-conditioning coils discharges by direct connection to a lavatory tailpiece or to an approved accessible inlet on a bathtub overflow, the connection shall be located in the area controlled by the same person controlling the air-conditioned space. 310.7 Female Plastic Connections. Female plastic screwed fittings shall be used with plastic male fittings and plastic male threads. Female plastic threaded connections shall not be allowed to be used when threaded onto a male
metallic connection.
311.0 Heating or Cooling Air System. 311.1 Source. A heating or cooling air system shall be provided with return air, outside air, or both. A heating or cooling air system regulated by this code and designed to replace required ventilation shall be arranged to discharge into a conditioned space not less than the amount of outside air specified in Chapter 4.
CMC § 1220.4.4 Medium relevance — show source text
1220.4.4 Poured Structural Concrete Slab Sys- tems. Where tubes are embedded in a structural concrete slab, such tubes shall not be larger in outside dimension than one-third of the overall thickness of the slab and shall be spaced not less than three diameters on center except within 10 feet (3048 mm) of the distribution manifold. The top of the tubing shall be embedded in the slab not less than 2 inches (51 mm) below the surface of the finished concrete slab.
1220.4.5 Slab Penetration Tube and Joint Protec-
tion. Where embedded in or installed under a concrete slab, tubing shall be protected from damage at penetrations of the slab with protective sleeving approved by the tubing manufacturer. The space between the tubing and sleeve shall be sealed with an approved sealant compatible with the tubing. The tubing at the location of an expansion joint in a concrete slab shall be encased in a protective pipe sleeve that covers the tubing not less than 12 inches (305 mm) on either side of the joint or the tubing shall be installed below the slab. 1220.4.6 Concrete Slab Preparation. A solid foundation shall be prepared before the tubing is installed. Compaction shall be used for slabs, sidewalks, and driveways.
TABLE 1220.4.2
MAXIMUM LOOP LENGTHS FOR SNOW
AND ICE MELT SYSTEMS [1,2]
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm
Notes: 1 The total PE-RT and PEX loop lengths consist of two separate sections, the active loop, and the leader length. The active loop is installed within the heated slab. The leader length is the total distance to and from the manifold and heated slab, including any vertical distances. 2 The manifolds shall be installed as close to the snow melt area as possible. 3 In concrete use minimum Type L copper water tubing. In bituminous pavement use a Type K copper water tubing.
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shall drain by indirect waste in accordance with Section 1001.4. Embedded piping underground or under floors is not required to be designed for draining the system.
1221.5 Condensate Drainage. Condensate drains from dehumidifying coils shall be constructed and sloped for condensate removal. Such drains shall be installed in accordance
with Section 310.0.
1221.6 Hydronic Fluid Disposal. Hydronic system fluids that contain additives such as antifreeze, corrosion inhibitors, and cleaning solutions shall be recycled or disposed of in an approved manner in accordance with Environmental Protection Agency (EPA), the Department of Health, and as required by the Authority Having Jurisdiction.
1221.7 Clearance to Combustibles. Hydronic piping where the exterior temperature exceeds 250°F (121°C) shall have a clearance of not less 1 inch (25.4 mm) to combustible materials.
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CMC § 37.95 Medium relevance — show source text
Exceptions:
(1) A condensing unit in a room or space where the cubical content exceeds 1000 cubic feet per horsepower (ft [3] /hp) (37.95 m [3] /kW) of the unit.
(2) A condensing unit in a room or space that has permanent gravity ventilation having an area of 2 square feet (0.2 m [2] ) or more to other rooms or openings exceeding 1000 ft [3] /hp (37.95 m [3] /kW).
1105.6 Prohibited Locations. Refrigeration systems or portions thereof shall not be located within a required exit enclosure. Refrigeration compressors exceeding 5 horsepowers (3.7 kW) rating shall be located not less than 10 feet (3048 mm) from an exit opening in a Group A; Group B; Group E; Group F; Group I; Group R, Division 1; or Group S Occupancy, unless separated by a one-hour fire-resistive occupancy separation.
1105.7 Condensate. Condensate from air-cooling coils shall be collected and drained to an approved location. Drain pans and coils shall be arranged to allow thorough drainage and access for cleaning. Where temperatures drop below freezing, heat tracing and insulation of condensate drains shall be installed.
1105.8 Defrost. Where defrost cycles are required for portions of the system, provisions shall be made for collection and disposal of the defrost liquid in a safe and sanitary man ner.
1105.9 Overflows. Where condensate or defrost liquids are generated in an attic or furred space, and structural damage will result from overflow, provisions for overflow shall be provided.
1105.10 Condensate, Defrost, and Overflow Dis- posal. Disposal of condensate, defrost, or overflow discharges shall comply with Section 310.0.
1105.11 Refrigerant Port Protection. Air conditioning refrigerant circuit access ports located outdoors shall be protected from unauthorized access with locking-type tamperresistant caps or in a manner approved by the Authority Having Jurisdiction.
Exception: Refrigerant ports in secure locations protected by walls or fencing and requiring key access.
1105.12 Storage. Refrigerants and refrigerant oils not charged within the refrigeration system shall be stored in accordance with Section 1105.12.1 and the fire code. Storage of materials in a refrigeration machinery room shall comply with the fire code.
1105.12.1 Storing Refrigerant. The total amount of refrigerant stored in a machinery room in all containers not provided with relief valves and piping in accordance with Section 1113.0 shall not exceed 330 pounds (149.7 kg). Refrigerant shall be stored in approved storage containers. Additional quantities of refrigerant shall be stored in an approved storage facility. [ASHRAE 15:11.5]
1106.0 Refrigeration Machinery Rooms.
1106.1 Where Required. Refrigeration systems shall be provided with a refrigeration machinery room where the conditions as outlined in Section 1106.1.1 through Section 1106.1.4 exist.
Exception: Refrigeration equipment shall be permitted to be located outdoors in accordance with ASHRAE 15.
1106.1.1 Quantity. The quantity of refrigerant in a single, independent refrigerant circuit of a system exceeds the amounts of Table 1102.3.
Frequently asked questions
Where must a condensate drain terminate so it is “readily observed”?
The code requires the terminating end of a pan drain or auxiliary overflow drain to be readily visible (for water heaters per § 305.5(1) and for auxiliary pans per § 310.2). Placing the visible outlet at an eave, accessible exterior wall, or adjacent visible receptor meets this intent.
Can I vent condensate to storm drain or across a public way?
No. Condensate or wastewater shall not drain over a public way; connections to the drainage system must be via approved indirect waste/receptors as required in § 310.1 and § 310.5.
If two condensing appliances share a drain, do I need a trap?
Yes. When multiple appliances connect to a common indirect waste pipe the connections must be protected by an ASME A112.18.8 sanitary waste valve, a condensate trap complying with IAPMO IGC 196, or a trap with a trap primer, per § 310.4.
Is a water heater relief valve allowed to drain into the pan?
No — discharge from a relief valve into a drainage pan is prohibited by § 305.5(4). Relief valve discharge must be routed to an approved location per manufacturer and plumbing code.
How large must a pan drain be?
Minimum pan drain or auxiliary overflow drain size is 3/4 inch (20 mm) nominal as required by § 305.5(1) and referenced in overflow pan provisions in § 310.2.
Who can approve non‑standard condensate routing or pump installations?
The Authority Having Jurisdiction (AHJ) may approve condensate pumps and alternative routing or sizing if justified; follow § 310.1.1 and coordinate with the AHJ.
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