CRC · California Residential Code
Indirect wastes, air gaps and grease interceptors
Indirect wastes (equipment drips, refrigeration condensate, food‑service drains) must dump into the building drainage only through a proper air gap or air break and be sized/trapped per CRC rules; commercial grease‑producing fixtures must each be trapped and vented into approved grease interceptors sized by the code and maintained regularly (local authority can require extra measures).
Last reviewed: July 6, 2026
What the code requires — plain English (controlling §§)
The California Residential Code requires that indirect waste piping discharge to the drainage system only through an air gap or air break, and that indirect-waste piping be sized, trapped and routed so it can be cleaned and will not backflow into equipment (§ 803.0). Grease‑laden wastes from commercial food‑service fixtures must be routed through approved grease interceptors, with each fixture individually trapped and vented and interceptors maintained per the Authority Having Jurisdiction (§ 1014.1). § 803.0 ; § 1014.1 .
Indirect wastes must discharge by an air gap or air break into a receptor; grease‑producing fixtures must drain to properly sized, trapped and vented interceptors that are maintained. § 801.2 § 1014.1
Requirements in detail
Key definitions (first mention bolded)
- Indirect waste pipe — a pipe that does not connect directly to the building drainage but discharges into a fixture, interceptor or receptor that is connected to the drainage system. § 803.0
- Air gap / Air break — the physical separation required between the indirect‑waste outlet and the receptor rim (air‑gap minimum given below). § 801.2
- Grease interceptor / Hydromechanical grease interceptor — devices/appliances installed to intercept fats, oils and grease (FOG) before they enter the sanitary drainage system; hydromechanical units are rated by flow and separation efficiency. § 1014.2
Indirect waste piping (materials, sizing, traps, vents)
- Materials and joints must be appropriate for the service and acceptable to the Authority Having Jurisdiction. § 803.1–803.2
- Minimum sizes and lengths:
- Indirect waste piping less than 15 feet (4572 mm) shall be not less than the diameter of the drain outlet or tailpiece and in no case less than 1/2 inch (15 mm). § 803.3
- For food‑service equipment the code sets larger minimums: except refrigeration coils/ice machines, the indirect waste pipe shall be not smaller than the unit drain but not less than 1 inch (25 mm) and the maximum developed length 15 feet; ice‑makers may be 3/4 inch (20 mm). § 801.3.1
- Traps & vents:
- Indirect waste pipes exceeding 5 feet but less than 15 feet must be directly trapped; such traps need not be vented. § 803.3
- Vents from indirect waste piping must extend separately to the outside air and may not combine with a sewer‑connected vent. § 803.3
- Cleanouts: angles and changes of direction in indirect waste piping must be provided with cleanouts for flushing/cleaning. § 803.3
Indirect waste receptors (standpipes, splash control, location)
- Receptors must be approved for the use, shaped/capacity to prevent splashing or flooding, and be readily accessible for inspection/cleaning. § 804.1
- Clothes washer standpipe limits: standpipe height 18–30 inches above trap weir; trap rough‑in 6–18 inches above finished floor. § 804.1
- Walk‑in cooler floor drains may discharge to an outside receptor provided the receptor rim is at least 6 inches (152 mm) lower than the lowest floor drain; such drains must be trapped, individually vented and discharge through an air gap or air break (full‑size air gap required where under vacuum). § 801.3.2
Grease interceptors — required features and operation
- Each fixture discharging into a grease interceptor must be individually trapped and vented. § 1014.1.1
- Interceptors must be maintained in efficient operating condition by periodic removal of accumulated grease; collected grease must not be returned to the drainage or sewer. The AHJ may require additional equipment or mandated maintenance programs. § 1014.1.2
- Food waste disposers and dishwashers: generally not allowed to discharge into grease interceptors; exception allows disposers to discharge into interceptors designed to receive food waste. § 1014.1.3
- Hydromechanical interceptors: flow controls and vents are required so total flow does not exceed the interceptor’s rated flow; the AHJ may allow listed units with integral flow controls per the manufacturer’s instructions. § 1014.2
- Sizing rule (hydromechanical): the total capacity in gallons of fixtures discharging into a hydromechanical interceptor shall not exceed two and one‑half times (2.5×) the certified gallon‑per‑minute (gpm) flow rate of the interceptor (see Table 1014.2.1). § 1014.2.1
Decision‑relevant dimensions & values (quick reference table)
| Feature / question | Required value | Code Reference |
|---|---|---|
| Minimum air‑gap vertical clearance from indirect waste outlet to receptor rim | 1 inch (25.4 mm) | § 801.2 |
| Minimum indirect waste pipe diameter (general, <15 ft) | Not less than the unit drain; in no case < 1/2 inch (15 mm) | § 803.3 |
| Minimum indirect waste pipe for food equipment (except ice makers) | Not less than unit drain; ≥ 1 inch (25 mm) | § 801.3.1 |
| Maximum developed length for indirect waste pipe | 15 feet (4572 mm) (food equipment rule) | § 801.3.1 |
| Where a trap is required for indirect waste | If length > 5 ft and < 15 ft, trap required (venting not required) | § 803.3 |
| Hydromechanical interceptor capacity rule | Total fixture gallons ≤ 2.5 × interceptor certified gpm | § 1014.2.1 |
| Fixtures prohibited from draining through grease interceptors | Toilets, urinals, and similar fixtures | § 1014.3.2.1 |
Exceptions & special cases
- The code allows an air break (less protective than a full air gap) where no potable cross‑connection risk exists; a full‑size air gap is required where the indirect waste is under vacuum or if contamination risk is present. § 801.2, § 801.3.2
- Food waste disposers may discharge to a grease interceptor only if the interceptor is specifically designed to receive food‑waste disposals (exception in § 1014.1.3). § 1014.1.3
- Grease interceptors are generally not required for individual dwelling units or private living quarters (see guidance in § 1014 series). The AHJ has authority to require interceptors where grease would harm the collection/WWTP. § 1014 (general)
Common mistakes
- Confusing an air gap (physical separation) with an air break and using the weaker option where a full air gap is required (food‑handling or vacuum conditions). See § 801.2 and § 801.3.3. file
- Making an indirect waste pipe smaller than the unit’s drain or below the code minimums (1/2" general; 1" for many food units). § 803.3, § 801.3.1 file
- Failing to trap indirect waste pipes that exceed 5 feet in developed length. § 803.3
- Connecting toilets/urinals or returning collected grease to the sewer through an interceptor. § 1014.3.2.1, § 1014.1.2 file
- Installing a dishwasher or disposal into an interceptor that is not designed for food‑waste disposers (violates § 1014.1.3 exception/requirement). § 1014.1.3
Worked example — small cafe three‑compartment sink
Situation: A café has one three‑compartment sink. Each compartment measures 24 in × 24 in × 12 in (internal). The owner wants to use a hydromechanical grease interceptor inside the building.
Step 1 — compute compartment volume: the code example shows a 24×24×12 compartment equals about 44.9 gallons (example in the code). Use the code’s fixture‑capacity method (volume /231 × fill factor, then divide by drain period) to derive the fixture load. See the example and method in the code.
Step 2 — apply the hydromechanical sizing rule: the total gallons of fixtures discharging into the interceptor must not exceed 2.5 × the interceptor’s certified gpm rating (§ 1014.2.1). If the effective fixture capacity (after fill factor and drain period) is, for example, 50 gallons, then required certified interceptor flow = 50 ÷ 2.5 = 20 gpm minimum. § 1014.2.1
Step 3 — installation checks: ensure each sink compartment (fixture) is individually trapped and vented into the grease interceptor per § 1014.1.1, and that the interceptor is accessible for maintenance and has a maintenance plan (or AHJ‑required program). § 1014.1.1–1014.1.2
Related provisions (quick list)
- § 801.2 — Air gap/air break minimums and requirements.
- § 801.3.1 / § 801.3.2 / § 801.3.3 — Food‑handling equipment indirect waste sizing and air‑gap requirements.
- § 804.1 — Indirect waste receptor (standpipe) requirements and heights.
- § 1009.1–1009.6 — Interceptor approvals, design and maintenance (general interceptor rules).
- § 1014.2 / § 1014.3 — Hydromechanical and gravity grease interceptor design, flow controls and permitted/forbidden drains. file
Code references
Grounded in the retrieved California Residential Code — click a citation to read the verbatim passage:
CRC § 0.06 High relevance — show source text
For SI units: 1 inch = 25 mm, 1 gallon per minute = 0.06 L/s
Notes: 1 For interceptor sizing by the fixture capacity see the example below. 2 1 ∕ 4 inch slope per foot (20.8 mm/m) based on Manning’s formula with friction factor N = 0.012.
EXAMPLE 1014.2.1
SIZING HYDROMECHANICAL GREASE INTERCEPTOR(S)
USING FIXTURE CAPACITY
Step 1: Determine the flow rate from each fixture.
[Length] X [Width] X [Depth] / [231] = Gallons X [0.75 fill factor] / [Drain
Period (1 minute or 2 minutes)]
Step 2: Calculate the total load from fixtures that discharge into
the interceptor.
FIXTURES COMPART-
MENTSLOAD
(gallons)SIZE OF
GREASE
INTERCEPTOR
ONE-MINUTE
DRAINAGE
PERIOD
(gpm)TWO-
MINUTE
DRAINAGE
PERIOD
(gpm)
Compartment
size–– –– –– ––
24 inches x 24
inches x 12
inches2 44.9 –– ––
Hydrant–– 3 –– ––
Rated
Appliance–– 2 –– ––
–––– 49.9 50 25 For SI units: 1 inch = 25.4 mm, 1 gallon per minute = 0.06 L/s, 1 gallon =
3.785 L
1014.3 Gravity Grease Interceptors. Required gravity grease interceptors shall comply with the provisions of Section 1014.3.1 through Section 1014.3.7.
1014.3.1 General. The provisions of this section shall apply to the design, construction, installation, and testing of commercial kitchen gravity grease interceptors.
1014.3.2 Waste Discharge Requirements. Waste discharge in establishments from fixtures and equipment
For SI units: 1 inch = 25.4 mm, 1 gallon per minute = 0.06 L/s, 1 gallon =
3.785 L
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TRAPS AND INTERCEPTORS
which contain grease, including but not limited to, scullery sinks, pot and pan sinks, dishwashers, soup kettles, and floor drains located in areas where grease-containing materials exist, shall be permitted to be drained into the sanitary waste through the interceptor where approved by the Authority Having Jurisdiction.
1014.3.2.1 Toilets and Urinals. Toilets, urinals, and other similar fixtures shall not drain through the interceptor.
1014.3.2.2 Inlet Pipe. Waste shall enter the interceptor through the inlet pipe.
1014.3.3 Design. Gravity interceptors shall be constructed in accordance with the applicable standard in Chapter 17 or the design approved by the Authority Having Jurisdiction.
CRC § 1014.1.1 High relevance — show source text
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TRAPS AND INTERCEPTORS
1014.1.1 Trapped and Vented. Each fixture discharging into a grease interceptor shall be individually trapped and vented in an approved manner.
1014.1.2 Maintenance. Grease interceptors shall be maintained in efficient operating condition by periodic removal of the accumulated grease and latent material. No such collected grease shall be introduced into drainage piping or a public or private sewer. Where the Authority Having Jurisdiction determines that a grease interceptor is not being properly cleaned or maintained, the Authority Having Jurisdiction shall have the authority to mandate the installation of additional equipment or devices and to mandate a maintenance program.
1014.1.3 Food Waste Disposers and Dishwash- ers. No food waste disposer or dishwasher shall be connected to or discharge into a grease interceptor. Commercial food waste disposers shall be permitted to discharge directly into the building’s drainage system.
Exception: Food waste disposers shall be permitted to discharge to grease interceptors that are designed to receive the discharge of food waste.
1014.2 Hydromechanical Grease Interceptors. Plumbing fixtures or equipment connected to a Type A and B hydromechanical grease interceptor shall discharge through an approved type of vented flow control installed in a readily accessible and visible location. Flow control devices shall be
designed and installed so that the total flow through such device or devices shall at no time be greater than the rated flow of the connected grease interceptor. No flow control device having adjustable or removable parts shall be approved. The vented flow control device shall be located such that no system vent shall be between the flow control and the grease interceptor inlet. The vent or air inlet of the flow control device shall connect with the sanitary drainage vent system, as elsewhere required by this code, or shall terminate through the roof of the building, and shall not terminate to the free atmosphere inside the building.
Exception: Listed grease interceptors with integral flow controls or restricting devices shall be installed in an accessible location in accordance with the manufacturer’s installation
instructions.
1014.2.1 Capacity. The total capacity in gallons (gal) (L) of fixtures discharging into a hydromechanical grease interceptor shall not exceed two and one-half times the certified gallon per minute (gpm) (L/s) flow rate of the interceptor in accordance with Table 1014.2.1.
For this section, the term “fixture” shall mean and include each plumbing fixture, appliance, apparatus, or other equipment required to be connected to or discharged into a grease interceptor by a provision of this section.
1014.2.2 Vent. A vent shall be installed downstream of
hydromechanical grease interceptors in accordance with the requirements of this code.
TABLE 1014.2.1
HYDROMECHANICAL GREASE INTERCEPTOR SIZING USING GRAVITY FLOW RATES [1]
CRC § 3.3.74 High relevance — show source text
a. Shall be designed and installed to prevent splashing outside of the lavatory.
b. Shall be well-fitted and sealed to prevent water leaks onto or into the cabinetry or wall spaces.
c. Design of lavatories and cabinetry shall not permit storage beneath the fixture basin.
d. Shall be constructed of nonporous material. Hangers. See Supports. Health Care Facility’s Governing Body. The person or persons who have the overall legal responsibility for the operation of a health care facility. [NFPA 99:3.3.74] High Hazard. See Contamination. Horizontal Branch. A drainpipe extending laterally from soil or waste stack or building drain with or without vertical sections or branches, which receives the discharge from one or more fixture drains and conducts it to the soil or waste stack or the building drain. Horizontal Pipe. A pipe or fitting that is installed in a horizontal position or which makes an angle of less than 45 degrees (0.79 rad) with the horizontal.
Hot Water. Water at a temperature exceeding or equal to 120°F (49°C). House Drain. See Building Drain. House Sewer. See Building Sewer. Hydromechanical Grease Interceptor. A plumbing appurtenance or appliance that is installed in a sanitary drainage system to intercept nonpetroleum fats, oil, and
grease (FOG) from a wastewater discharge and is identified by flow rate, and separation and retention efficiency. The design incorporates air entrainment, hydromechanical separation, interior baffling, or barriers in combination or separately, and one of the following:
(1) External flow control, with an air intake (vent), directly connected.
(2) External flow control, without air intake (vent), directly connected.
(3) Without external flow control, directly connected.
(4) Without external flow control, indirectly connected.
These interceptors comply with the requirements of Table 1014.2.1. Hydromechanical grease interceptors are generally installed inside.
211.0 – I –
Indirect-Fired Water Heater. A water heater consisting of a storage tank equipped with an internal or external heat exchanger used to transfer heat from an external source to heat potable water. The storage tank either contains heated potable water or water supplied from an external source, such as a boiler.
Indirect Waste Pipe. A pipe that does not connect directly to the drainage system but conveys liquid wastes by discharging into a plumbing fixture, interceptor, or receptacle that is directly connected to the drainage system.
Individual Vent. A pipe installed to vent a fixture trap, and that connects with the vent system above the fixture served or terminates in the open air.
Industrial Waste. Liquid or water-borne waste from industrial or commercial processes, except domestic sewage.
Insanitary. A condition that is contrary to sanitary principles or is injurious to health.
Conditions to which “insanitary” shall apply include the following:
(1) A trap that does not maintain a proper trap seal.
(2) An opening in a drainage system, except where lawful that is not provided with an approved liquid-sealed trap.
(3) A plumbing fixture or other waste discharging receptor or device that is not supplied with water sufficient to flush and maintain the fixture or receptor in a clean condition.
(4) A defective fixture, trap, pipe, or fitting.
CRC § 1004.1 High relevance — show source text
Drum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1004.1
Floor drains . . . . . . . . . . . . . . . . . . . . . . .704.3, 1003.1,
1006.0, 1007.1
Food storage areas . . . . . . . . . . . . . . . . .418.4, 801.3.2 For three-compartment
sinks or three lavatories . . . . . . . . . . . . . . . . . .1001.2
From fixture, distance of . . . . . . . . . . . . . . . . . . . .1001.2
From vent, distance of . . . . . . . . . .1002.2, Table 1002.2
Gray water system . . . . . . . . . . . . . . . . . . . . . .1503.9.6 Grease interceptors . . . . . . . . . . . . . . . . . . . . . .1014.1.1
Indirect wastes . . . . . . . . . . . . . . . . . . . . . . . . . . .803.3
Integral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1001.2
Island sinks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .909.1
Materials . . . . . . . . . . . . . . . . . . . . .807.2, 906.6, 1003.1
Minimum size . . . . . . . . . . . .702.1, Table 702.1, 1003.3
Nonwater urinals . . . . . . . . . . . . . . . . . . . . . . . . .412.1.1
Prohibited types . . . . . . . . . . . . . . . . . . . . . . . . . .1004.0 Required . . . . . . . . . . . . . . . . . . . . . . . . .1001.0, 1101.15
Seal . . . . . . . . . . . . . . . . . . . . . . .222.0, 412.1.1, 912.2,
1005.0, 1007.1, E 501.6
Seal primer . . . . . . . . . . . . . . . . . . . . . . . .222.0, 1007.1 Separate for each fixture . . . . . . . . . . . . . . . . . . .1001.2 Slip joints . . . . . . . . . . . . . . . . . . . . . . . .705.9.1, 1003.2 Standpipe receptors . . . . . . . . . . . . . . . . . . . . . . .804.1
Storm drains and leaders . . . . . . . . . . . . . . . . . .1101.15
CRC § 901.0 High relevance — show source text
H 901.0 Commercial or Industrial Special Liquid- Waste Disposal.
H 901.1 Interceptor. Where liquid wastes contain excessive amounts of grease, garbage, flammable wastes, sand, or other ingredients that affect the operation of a private sewage disposal system, an interceptor for such wastes shall be installed.
H 901.2 Installation. Installation of such interceptors shall comply with Section 1009.0 of this code, and their location shall comply with Table H 101.8 of this appendix. H 901.3 Sampling Box. A sampling box shall be installed where required by the Authority Having Jurisdiction. H 901.4 Design and Structural Requirement. Interceptors shall be of approved design and be not less than two compartments. Structural requirements shall comply with Section H 501.0 of this appendix.
H 901.5 Location. Interceptors shall be located as close to the source as possible and be accessible for servicing. Necessary manholes for servicing shall be at grade level and be gastight.
H 901.6 Waste Discharge. Waste discharge from interceptors shall be permitted to be connected to a septic tank or other primary system or be disposed into a separate disposal system. H 901.7 Design Criteria. A formula shall be permitted to be adapted to other types of occupancies with similar wastes. (See Chart H 901.7)
H 1001.0 Inspection and Testing. H 1001.1 Inspection. Inspection requirements shall comply with the following:
(1) Applicable provisions of Section 105.0 of this code and this appendix shall be required. Plans shall be required in accordance with Section 103.3 of this code.
(2) System components shall be properly identified as to manufacturer. Septic tanks or other primary systems shall have the rated capacity permanently marked on the unit.
(3) Septic tanks or other primary systems shall be installed on dry, level, well-compacted soil.
(4) Where design is predicated on soil tests, the system shall be installed at the same location and depth as the tested
area.
H 1001.2 Testing. Testing requirements shall comply with the following:
(1) Septic tanks or other primary components shall be filled with water to flow line before requesting an inspection. Seams or joints shall be left exposed (except the bottom), and the tank shall remain watertight.
(2) A flow test shall be performed through the system to the point of effluent disposal. All lines and components shall
CHART H 901.7
RECOMMENDED DESIGN CRITERIA
GREASE AND GARBAGE, COMMERCIAL KITCHENS Number of meals per peak hour x Waste flow rate [1] x Retention time [2] x Storage factor [3] = (Interceptor size liquid capacity)
SAND-SILT OIL, AUTO WASHERS vehicles Number of per hour x Waste flow rate [1] x Retention time [2] x Storage factor [3] = (Interceptor size liquid capacity)
SILT-LINT GREASE, LAUNDRIES, LAUNDROMATS
Number of x 2 cycles per x Waste flow x Retention time [2] = Storage factor [3] = Interceptor size machines hour rate [1] (liquid capacity)
Notes: 1 For waste flow rate see Table H 201.1(4). 2 Retention Times:
CRC § 1007.2 Medium relevance — show source text
1007.2 Trap Seal Primers. Potable water supply trap seal primer valves shall comply with ASSE 1018. Drainage or electronic design type trap seal primer devices shall comply with ASSE 1044 or IAPMO PS 76.
1008.0 Building Traps. 1008.1 General. Building traps shall not be installed except where required by the Authority Having Jurisdiction. Each building trap where installed shall be provided with a cleanout and with a relieving vent or fresh-air intake on the inlet side of the trap, which needs not be larger than one-half the diameter of the drain to which it connects. Such relieving vent or fresh-air intake shall be carried above grade and terminate in a screened outlet located outside the building.
1009.0 Interceptors (Clarifiers) and Separators.
1009.1 Where Required. Interceptors (clarifiers) (including grease, oil, sand, solid interceptors, etc.) shall be required
by the Authority Having Jurisdiction where they are necessary for the proper handling of liquid wastes containing grease, flammable wastes, sand, solids, acid or alkaline substances, or other ingredients harmful to the building drainage system, the public or private sewer, or to public or private sewage disposal. A list of acceptable interceptor standards is referenced in Table 1009.1.
TABLE 1009.1 APPROVED INTERCEPTORS (CLARIFIERS)
APPLICATION STANDARD
Fats, Oil, Grease
(FOG)ASME A112.14.3, ASME A112.14.4,
ASME A112.14.6, CSA B481,
ANSI/CAN/IAPMO Z1001,
PDI G-101, PDI G-102Solid Waste IAPMO IGC 167
Non-petroleum OilASME A112.14.6, IAPMO PS 80,
PDI G-102
Petroleum OilASTM D6104, IAPMO IGC 183,
IAPMO IGC 3251009.2 Approval. The size, type, and location of each interceptor (clarifier) or separator shall be approved by the Authority Having Jurisdiction. Except where otherwise specifically permitted, no wastes other than those requiring treatment or separation shall be discharged into an interceptor (clarifier). 1009.3 Design. Interceptors (clarifiers) for sand and similar heavy solids shall be so designed and located as to be readily accessible for cleaning and shall have a water seal of not less than 6 inches (152 mm). 1009.4 Relief Vent. Interceptors (clarifiers) shall be so designed that they will not become air-bound where closed covers are used. Each interceptor (clarifier) shall be properly vented.
CRC § 1009.1 Medium relevance — show source text
TABLE 1009.1 APPROVED INTERCEPTORS (CLARIFIERS)
APPLICATION STANDARD
Fats, Oil, Grease
(FOG)ASME A112.14.3, ASME A112.14.4,
ASME A112.14.6, CSA B481,
ANSI/CAN/IAPMO Z1001,
PDI G-101, PDI G-102Solid Waste IAPMO IGC 167
Non-petroleum OilASME A112.14.6, IAPMO PS 80,
PDI G-102
Petroleum OilASTM D6104, IAPMO IGC 183,
IAPMO IGC 3251009.2 Approval. The size, type, and location of each interceptor (clarifier) or separator shall be approved by the Authority Having Jurisdiction. Except where otherwise specifically permitted, no wastes other than those requiring treatment or separation shall be discharged into an interceptor (clarifier). 1009.3 Design. Interceptors (clarifiers) for sand and similar heavy solids shall be so designed and located as to be readily accessible for cleaning and shall have a water seal of not less than 6 inches (152 mm). 1009.4 Relief Vent. Interceptors (clarifiers) shall be so designed that they will not become air-bound where closed covers are used. Each interceptor (clarifier) shall be properly vented.
1009.5 Location. Each interceptor (clarifier) cover shall be readily accessible for servicing and maintaining the interceptor (clarifier) in working and operating condition. The use of ladders or the removal of bulky equipment to service interceptors (clarifiers) shall constitute a violation of accessibility. Location of interceptors (clarifiers) shall be shown on the approved building plan. 1009.6 Maintenance of Interceptors. Interceptors shall be maintained in efficient operating condition by periodic removal of accumulated grease, scum, oil, or other floating substances and solids deposited in the interceptor. 1009.7 Discharge. The waste pipe from oil and sand interceptors shall discharge as approved by the Authority Having Jurisdiction.
1010.0 Slaughterhouses, Packing Establishments, etc.
1010.1 General. A fish, fowl, and animal slaughterhouse or establishment; a fish, fowl, and meat packing or curing establishment; a soap factory, tallow-rendering, fat-rendering, and a hide-curing establishment shall be connected to and shall drain or discharge into an approved grease interceptor (clarifier).
TABLE 1009.1 APPROVED INTERCEPTORS (CLARIFIERS)
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TRAPS AND INTERCEPTORS
1010.2 Meat and Poultry Processing Plants. [AGR]
1010.2.1 Drainage and Plumbing Systems. Drainage and plumbing systems shall meet the require- ments of Section 724.0.
1010.2.1.1 Each floor drain shall be equipped with a deep-seal trap.
CRC § 1015.4 Medium relevance — show source text
1015.4 Performance. FOG disposal systems shall produce an effluent quality not to exceed 5.84 grains per gallon (gr/gal) (100 mg/L) FOG. 1015.5 [OSHPD 1, 1R, 2, 3, 4 & 5] Grease interceptors shall not be installed in food preparation area of kitchens. 1015.6 [OSHPD 1, 1R, 2, 3, 4 & 5] Grease interceptors shall be installed outside of the kitchen area in location affording ease of maintenance and servicing.
1016.0 Sand Interceptors.
1016.1 Discharge. Where the discharge of a fixture or drain contains solids or semi-solids heavier than water that would be harmful to a drainage system or cause a stoppage within the system, the discharge shall be through a sand interceptor. Multiple floor drains shall be permitted to discharge into one sand interceptor. 1016.2 Authority Having Jurisdiction. Sand interceptors are required where the Authority Having Jurisdiction deems it advisable to have a sand interceptor to protect the drainage system. 1016.3 Construction and Size. Sand interceptors shall be built of brick or concrete, prefabricated coated steel, or other watertight material. The interceptor shall have an interior baffle for full separation of the interceptor into two sections. The outlet pipe shall be the same size as the inlet pipe of the sand interceptor, the minimum being 3 inches (80 mm), and the baffle shall have two openings of the same diameter as the outlet pipe and at the same invert as the outlet pipe. These openings shall be staggered so that there cannot be a straight line flow between the inlet pipe and the outlet pipe. The invert of the inlet pipe shall be no lower than the invert of the outlet pipe.
The sand interceptor shall have a minimum dimension of 2 square feet (0.2 m [2] ) for the net free opening of the inlet section and a minimum depth under the invert of the outlet pipe of 2 feet (610 mm).
For each 5 gpm (0.3 L/s) flow or fraction thereof over 20 gpm (1.26 L/s), the area of the sand interceptor inlet section is to be increased by 1 square foot (0.09 m [2] ). The outlet section shall at all times have a minimum area of 50 percent of the inlet section.
The outlet section shall be covered by a solid removable cover, set flush with the finished floor, and the inlet section shall have an open grating, set flush with the finished floor and suitable for the traffic in the area in which it is located.
1016.4 Separate Use. Sand and similar interceptors for every solid shall be so designed and located as to be readily accessible for cleaning, shall have a water seal of not less than 6 inches (152 mm), and shall be vented.
1017.0 Oil and Flammable Liquid Interceptors.
1017.1 Interceptors Required. Repair garages and gasoline stations with grease racks or grease pits, and factories that have oily, flammable, or both types of wastes as a result of manufacturing, storage, maintenance, repair, or testing processes, shall be provided with an oil or flammable liquid interceptor. Floor drains in such locations shall be connected directly to oil and flammable liquid interceptors.
CRC § 1.11.0. Medium relevance — show source text
This state agency does not adopt sections identified with the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.0.
2025 CALIFORNIA PLUMBING CODE 179
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
180 2025 CALIFORNIA PLUMBING CODE
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
CHAPTER 8
INDIRECT WASTES
801.0 General.
801.1 Applicability. This chapter shall govern the materials, design, and installation of indirect waste piping, receptors, and connections; and provisions for discharge and disposal of condensate wastes, chemical wastes, industrial wastes, and clear water wastes.
801.2 Air Gap or Air Break Required. Indirect waste piping shall discharge into the building drainage system through an air gap or air break as set forth in this code. Where a drainage air gap is required by this code, the minimum vertical distance as measured from the lowest point of the indirect waste pipe or the fixture outlet to the flood-level rim of the receptor shall be not less than 1 inch (25.4 mm). 801.3 Food and Beverage Handling Establishments. Establishments engaged in the storage, preparation, selling, serving, processing, or other handling of food and beverage involving the following equipment that requires drainage shall provide indirect waste piping for refrigerators, refrigeration coils, freezers, walk-in coolers, iceboxes, ice-making machines, steam tables, egg boilers, coffee urns and brewers, hot-and-cold drink dispensers, and similar equipment. 801.3.1 Size of Indirect Waste Pipes. Except for refrigeration coils and ice-making machines, the size of the indirect waste pipe shall be not smaller than the drain on the unit, but shall be not smaller than 1 inch (25 mm), and the maximum developed length shall not exceed 15 feet (4572 mm). Indirect waste pipe for ice-making machines shall be not less than the drain on the unit and in no case less than [3] ⁄ 4 of an inch (20 mm). 801.3.2 Walk-In Coolers. For walk-in coolers, floor drains shall be permitted to be connected to a separate drainage line discharging into an outside receptor. The flood-level rim of the receptor shall be not less than 6 inches (152 mm) lower than the lowest floor drain. Such floor drains shall be trapped and individually vented. Cleanouts shall be provided at 90 degree (1.57 rad) turns and shall be accessibly located. Such waste shall discharge through an air gap or air break into a trapped and vented receptor, except that a full-size air gap is required where the indirect waste pipe is under vacuum. 801.3.3 Food-Handling Fixtures. Food-preparation sinks, steam kettles, potato peelers, ice cream dipper wells, and similar equipment shall be indirectly connected to the drainage system by means of an air gap.
CRC § 222.0 Medium relevance — show source text
TRANSITION GAS RISER . . . . . . . . . . . . . .222.0, 1210.4.4
TRANSITION JOINTS . . . . . . . . . . . . . . . . . . . . . . . .705.9.4
TRAPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Chapter 10
Arms . . . . . . . . . . . . . . . . . .222.0, Table 702.1, 707.14,
1002.2, Table 1002.2, 1002.3
Bar and fountain sinks . . . . . . . . . . . . . . . . .801.4, 902.2
Building . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1008.0
Bottle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1004.1
Condensers and sumps . . . . . . . . . . . . . . . . . . . . .810.1
Crown weir . . . . . . . . . . . . . . . . . . .222.0, 409.6, 905.5,
1001.2, 1002.2, 1002.4
Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .222.0
Drum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1004.1
Floor drains . . . . . . . . . . . . . . . . . . . . . . .704.3, 1003.1,
1006.0, 1007.1
Food storage areas . . . . . . . . . . . . . . . . .418.4, 801.3.2 For three-compartment
sinks or three lavatories . . . . . . . . . . . . . . . . . .1001.2
From fixture, distance of . . . . . . . . . . . . . . . . . . . .1001.2
From vent, distance of . . . . . . . . . .1002.2, Table 1002.2
Gray water system . . . . . . . . . . . . . . . . . . . . . .1503.9.6 Grease interceptors . . . . . . . . . . . . . . . . . . . . . .1014.1.1
Indirect wastes . . . . . . . . . . . . . . . . . . . . . . . . . . .803.3
Integral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1001.2
Island sinks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .909.1
CRC § 8-903.2 Medium relevance — show source text
8-903.2 Residential occupancies.
8-903.2.1 Where toilet facilities are provided, alternative sewage disposal methods may be acceptable if approved by the local health department. In hotels, where private facilities are not provided, water closets at the ratio of one for each 15 rooms may be acceptable.
8-903.2.2 Toilet facilities are not required to be on the same floor or in the same building as sleeping rooms. Water-flush toilets may be located in a building immediately adjacent to the sleeping rooms. When alternative sewage disposal methods are utilized, they shall be located a minimum distance from the sleeping rooms or other locations as approved by the local health department.
8-903.2.3 Kitchen sinks shall be provided in all kitchens. The sink and countertop may be of any smooth nonabsorbent finish which can be maintained in a sanitary condition.
8-903.2.4 Hand washing facilities shall be provided for each dwelling unit and each hotel guest room. A basin and pitcher may be acceptable as adequate hand washing facilities.
8-903.2.5 Hot or cold running water is not required for each plumbing fixture, provided a sufficient amount of water is supplied to permit the fixture’s normal operation.
8-903.2.6 Bathtubs and lavatories with filler spouts less than 1 inch (25.4 mm) above the fixture rim may remain in use, provided there is an acceptable overflow below the rim.
8-903.2.7 Original or salvage water closets, urinals and flushometer valves shall be permitted in qualified historical buildings or properties. Historically accurate reproduction, nonlow-consumption water closets, urinals and flushometer valves shall be permitted except where historically accurate fixtures that comply with the regular code are available.
8-903.3 Materials. New nonhistorical materials shall comply with the regular code requirements. The enforcing agency shall accept alternative materials which do not create a safety hazard where their use is necessary to maintain the historical integrity of the building.
8-903.4 Drainage and vent systems. Plumbing fixtures shall be connected to an adequate drainage and vent system. The enforcing agency may require operational tests for drainage and vent systems which do not comply with applicable requirements of the regular code. Vent terminations may be installed in any location which, in the opinion of the enforcing agency, does not create a safety hazard.
8-903.5 Indirect and special wastes. Indirect and special waste systems shall be installed so that no safety hazard is created. Chemical or industrial liquid wastes which may detrimentally affect the sanitary sewer system shall be pretreated to render them safe prior to discharge.
8-903.6 Traps and interceptors. Traps and interceptors shall comply with the regular code requirements except that the enforcing agency shall accept solutions which do not increase the safety hazard. Properly maintained “S” and drum traps may remain in use.
8-903.7 Joints and connections.
8-903.7.1 Joints and connections in new plumbing systems shall comply with applicable requirements of the regular code.
8-903.7.2 Joints and connections in existing or restored systems may be of any type that does not create a safety hazard.
8-903.8 Water distribution. Plumbing fixtures shall be connected to an adequate water distribution system. The enforcing agency may require operational tests for water distribution systems which do not comply with applicable requirements of the regular code. Prohibited (unlawful) connections and cross connections shall not be permitted.
CRC § 1014.2.1. Medium relevance — show source text
(2) External flow control, without air intake (vent), directly connected.
(3) Without external flow control, directly connected.
(4) Without external flow control, indirectly connected.
These interceptors comply with the requirements of Table 1014.2.1. Hydromechanical grease interceptors are generally installed inside.
211.0 – I –
Indirect-Fired Water Heater. A water heater consisting of a storage tank equipped with an internal or external heat exchanger used to transfer heat from an external source to heat potable water. The storage tank either contains heated potable water or water supplied from an external source, such as a boiler.
Indirect Waste Pipe. A pipe that does not connect directly to the drainage system but conveys liquid wastes by discharging into a plumbing fixture, interceptor, or receptacle that is directly connected to the drainage system.
Individual Vent. A pipe installed to vent a fixture trap, and that connects with the vent system above the fixture served or terminates in the open air.
Industrial Waste. Liquid or water-borne waste from industrial or commercial processes, except domestic sewage.
Insanitary. A condition that is contrary to sanitary principles or is injurious to health.
Conditions to which “insanitary” shall apply include the following:
(1) A trap that does not maintain a proper trap seal.
(2) An opening in a drainage system, except where lawful that is not provided with an approved liquid-sealed trap.
(3) A plumbing fixture or other waste discharging receptor or device that is not supplied with water sufficient to flush and maintain the fixture or receptor in a clean condition.
(4) A defective fixture, trap, pipe, or fitting.
(5) A trap, except where in this code exempted, directly connected to a drainage system, the seal of which is not protected against siphonage and backpressure by a vent pipe.
(6) A connection, cross-connection, construction, or condition, temporary or permanent that would permit or make possible by any means whatsoever for an unapproved foreign matter to enter a water distribution system used for domestic purposes.
(7) The preceding enumeration of conditions to which the term “insanitary” shall apply, shall not preclude the application of that term to conditions that are, in fact, insanitary.
2025 CALIFORNIA PLUMBING CODE 37
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
DEFINITIONS
that maintains a periodic inspection program of production of labeled products, installations, equipment, or materials and by whose labeling the manufacturer indicates compliance with appropriate standards or performance in a specified manner.
Lavatories in Sets. Two or three lavatories that are served by one trap. Lavatory. [HCD 1 & HCD 2] “Lavatory” shall mean a plumbing fixture used for washing the hands, arms, face and head.
Leader. An exterior vertical drainage pipe for conveying storm water from roof or gutter drains. See Downspout. _**Limited-Density Owner-Built Rural Dwelling.
Frequently asked questions
What is the single simplest compliance step for indirect wastes?
Provide an approved receptor and an air gap (minimum 1 inch) between the indirect waste outlet and the receptor rim (or an appropriate air break where allowed). § 801.2
Do I need a grease interceptor for a single‑family home?
Generally no — grease interceptors are not required for individual dwelling units or private living quarters; the rules target commercial food‑service and other grease‑producing establishments. See the 1014 series and AHJ guidance. § 1014
Can a dishwasher discharge into a grease interceptor?
Not normally. Dishwashers and food waste disposers shall not discharge into a grease interceptor, unless the interceptor is specifically designed to receive the disposer’s discharge (exception). § 1014.1.3
If my indirect waste pipe is 10 feet long, do I need a trap?
Yes — indirect waste pipes over 5 ft but under 15 ft must be directly trapped (these traps need not be vented). § 803.3
How often must a grease interceptor be cleaned?
The code requires periodic removal of accumulated grease so the interceptor remains in efficient operating condition; the AHJ may mandate specific maintenance programs if not properly cleaned. § 1014.1.2
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