CPC · California Plumbing Code
Sewage ejectors, backwater valves, and sump/receiving tank requirements for below-sewer fixtures
If a bathroom or other fixtures are lower than the main sewer, the CPC requires those fixtures to drain into a watertight sump or receiving tank and then be pumped to the sewer. Pumps must meet minimum capacities and solids‑passage sizes, discharge piping must include backwater and gate valves, backwater valves must be accessible and listed, and sumps must be built, vented, and covered per the code.
Last reviewed: July 6, 2026
What the code requires — 2–4 sentences
In plain English: fixtures that drain at elevations below the crown of the main sewer must not discharge directly into the building sewer — they must first discharge by gravity into an approved, watertight sump or receiving tank, and the contents must then be lifted into the building drain/sewer by approved sewage ejectors or pumps sized and installed per code. The plumbing code sets minimum pump capacities and sizing, requires accessible backwater valves that meet a listing standard, and requires specific construction and vent/cover requirements for sumps and receiving tanks. The controlling sections are § 710.3, § 710.6, and § 710.8.
The single most important rule: any plumbing fixtures located below the main sewer crown must discharge to a watertight sump/receiving tank and be lifted by an approved ejector or pump sized and equipped to handle the fixtures served.
Requirements in detail
Key defined terms (first mention)
- Sewage ejector / sewage pump — mechanical device that lifts sewage from a sump or receiving tank into the building drain/sewer. § 710.3.
- Backwater valve — a valve designed to prevent reverse flow of sewage; must be accessible and meet the listed standard. § 710.6.
- Sump / receiving tank — the watertight vessel that receives gravity flow from below-sewer fixtures before lifting. § 710.8.
Sewage ejectors and pumps (what the CPC requires)
- Minimum discharge capacity: not less than 20 gpm (1.26 L/s) for an ejector receiving water closets or urinals. § 710.3 (1).
- Solid‑passage capability:
- For single‑dwelling units the ejector must be able to pass a 1-1/2‑inch (38 mm) diameter solid ball and the ejector discharge piping shall be not less than 2 inches (50 mm) and must include a backwater valve and gate valve. § 710.3 (2).
- For other than single‑dwelling units the ejector must pass a 2‑inch (51 mm) diameter solid ball, and the discharge piping shall be not less than 3 inches (80 mm) and must include a backwater valve and gate valve. § 710.3 (3).
Discharge piping and valves
- The discharge line from the ejector/pump must be pressure‑rated and provided with an accessible backwater or swing check valve and a gate or ball valve (gate/ball valve located on the discharge side of the backwater/check valve). § 710.4.
- Gate/ball valves in drainage piping must be fullway type and corrosion resistant; sizing and body material requirements per § 710.4. § 710.4.
Backwater valves (materials, location, listing)
- Backwater valves must be accessible for inspection/repair; if not continuously exposed they must be enclosed in a masonry pit with removable cover. § 710.6.
- Backwater valves must comply with ASME A112.14.1 or IAPMO IGC 305, have approved materials (cast‑iron, plastic, copper alloy, or other approved), non‑corrosive bearings/seats, self‑aligning discs and positive mechanical seal. § 710.6.
- Valves should remain open during low flows (to avoid screening solids) and not restrict capacity during peak loads; covers are typically bolted with gasket and valves bear manufacturer identification. § 710.6.
Sump and receiving tank construction (materials, covers, vents)
- Sumps and receiving tanks must be watertight and constructed of concrete, metal, or other approved materials. Poured concrete must be adequately reinforced; metal units must be of sufficient thickness and corrosion‑resistant coatings. § 710.8.
- Covers: sump tops require substantial covers with bolt‑and‑gasket‑type manhole or equivalent opening to permit inspection, repair, and cleaning. § 710.10.
- Venting: sumps must be vented with a pipe sized to maintain atmospheric pressure; vent size shall be not less than that required by Table 703.2 for the number/type of fixtures discharging into the sump, and in no case less than 1-1/2 inches (40 mm). No vent from an air‑operated ejector shall combine with other vents. § 710.10.
- Alarm and redundancy (where required): sumps/receiving tanks that are automatically discharged, and for “public use” occupancies, must have dual pumps/ejectors arranged to function alternately and capable of continuous running in case one fails; audio/visual alarm required. The lowest inlet must be at least 2 inches (51 mm) above the high‑water/starting level. § 710.9.
Sizing & building‑drain capacity
- Building drains/sewers receiving pump/ejector discharge must be sized to prevent overloading; allow 2 fixture units for each gallon per minute (gpm) of pump flow when converting pump discharge to fixture units for sizing. § 710.5.
Alternate systems permitted
- Grinder pump ejectors are permitted (see § 710.12) and have specific minimum discharge piping sizing and check/shutoff valve requirements. § 710.12 / § 710.12.1.
- Macerating toilet / pumped waste systems are permitted as an alternate where approved; must comply with ASME A112.3.4/CSA B45.9 and manufacturer instructions. § 710.13.
Decision‑relevant dimensions & values (quick reference table)
| Item | Required value (CPC) | Code Reference |
|---|---|---|
| Minimum ejector discharge capacity (water closets/urinals) | 20 gpm (1.26 L/s) | § 710.3 (1) |
| Solid‑passage (single dwelling) | 1‑1/2 in (38 mm) ball | § 710.3 (2) |
| Discharge piping min (single dwelling ejector) | 2 in (50 mm) | § 710.3 (2) |
| Solid‑passage (other than single dwelling) | 2 in (51 mm) ball | § 710.3 (3) |
| Discharge piping min (other than single dwelling) | 3 in (80 mm) | § 710.3 (3) |
| Sump vent min | Table 703.2 requirement OR not less than 1‑1/2 in (40 mm) | § 710.10 |
| Lowest inlet clearance to start level (alarm/dual pump req.) | 2 in (51 mm) | § 710.9 |
| Sump/tank construction | Watertight; concrete, metal, or approved material; reinforced/treated | § 710.8 |
| Backwater valve listing | ASME A112.14.1 or IAPMO IGC 305 | § 710.6 |
Exceptions & special cases
- Macerating toilet systems and pumped waste systems are allowed as alternatives where approved and when installed per the standard/manufacturer (see § 710.13).
- Grinder pumps are permitted; they have special minimum discharge piping sizing (§ 710.12 / 710.12.1).
- Fixtures that are not below the next upstream manhole are not required to be protected by a backwater valve per § 710.1 (backflow protection). If a fixture is below that elevation, a backwater valve is required. § 710.1.
If a specific manufacturer’s installation instructions require larger piping or different venting, the Authority Having Jurisdiction may require compliance with those instructions — the code allows listed/mfr‑instructions to control for listed devices (see the macerator and grinder pump sections). § 710.12–710.13.
Common mistakes
- Installing an ejector/pump with capacity < 20 gpm for water‑closet service. § 710.3 (1).
- Using too‑small discharge piping (e.g., < 2 in for a single‑family ejector serving a water closet). § 710.3 (2).
- Omitting an accessible backwater valve or burying the valve where it cannot be inspected/maintained; backwater valves must be accessible or in a pit with removable cover. § 710.6.
- Putting the shutoff/gate valve in the wrong position (the gate/ball valve must be located on the discharge side of the backwater/check valve). § 710.4.
- Not venting the sump to at least 1‑1/2 in or not providing the vent area required by Table 703.2; or improperly combining vents from air‑operated ejectors (prohibited). § 710.10.
- For public use occupancies: failing to provide dual pumps/ejectors, alarm, and required clearances. § 710.9.
Worked example — single‑family basement bathroom with a water closet + lavatory
Scenario: one basement bathroom below the crown of the main sewer with a water closet and lavatory discharging to a new sump.
Steps and numbers:
- Because the WC is below the crown of the main sewer, the fixtures must discharge to a watertight sump and be lifted by a pump/ejector. § 710.2.
- Choose a sewage ejector with minimum discharge capacity 20 gpm (meets § 710.3 (1)).
- For a single‑family unit the ejector must pass a 1‑1/2 in (38 mm) solid ball and the ejector discharge piping must be at least 2 in (50 mm) and be provided with a backwater valve and gate valve. Install accordingly. § 710.3 (2).
- Install the discharge line using approved pressure‑rated material, place an accessible backwater or swing check valve and a fullway gate/ball valve (gate/ball on discharge side of backwater). § 710.4.
- Construct the sump to be watertight (concrete with reinforcement or an approved manufactured metal tank with corrosion protection); provide a bolt‑and‑gasket manhole cover and a vent sized per Table 703.2 but not less than 1‑1/2 in. § 710.8 / § 710.10.
- Size the building drain receiving the pump discharge per § 710.5 (convert pump gpm to fixture units at 2 fixture units per gpm) to confirm the downstream gravity piping is adequate. § 710.5.
Related provisions (quick list)
- § 710.2 — Sewage discharge requirement for fixtures located below the crown level of the main sewer (general rule that starts the requirement to use sumps/ejectors).
- § 710.4 — Discharge line materials, check valves, and valve placement.
- § 710.5 — Sizing of building drains/sewers receiving pump discharge (fixture‑unit conversion).
- § 710.9 — Alarm and dual pump requirements for public‑use occupancy sumps.
- § 710.10 — Sump and receiving tank covers and venting requirements.
- § 710.11 — Air‑tank proportioning for air systems (where used).
- § 710.12 / § 710.12.1 — Grinder pump ejectors and discharge piping requirements.
- § 710.13 — Macerating / pumped waste system acceptance and requirements.
Code references
Grounded in the retrieved California Plumbing Code — click a citation to read the verbatim passage:
CPC § 710.2 High relevance — show source text
710.2 Sewage Discharge. Drainage piping serving fixtures that are located below the crown level of the main sewer shall discharge into an approved watertight sump or receiving tank, so located as to receive the sewage or wastes by gravity. From such sump or receiving tank, the sewage or other liquid wastes shall be lifted and discharged into the building drain or building sewer by approved ejectors, pumps, or other equally efficient approved mechanical devices. 710.3 Sewage Ejector and Pumps. A sewage ejector or sewage pump receiving the discharge of water closets or urinals:
(1) Shall have a discharge capacity of not less than 20 gpm (1.26 L/s).
(2) In single dwelling units, the ejector or pump shall be capable of passing an 1 [1] ⁄ 2 inch (38 mm) diameter solid ball, and the discharge piping of each ejector or pump
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shall have a backwater valve and gate valve, and be not less than 2 inches (50 mm) in diameter.
(3) In other than single-dwelling units, the ejector or pump shall be capable of passing a 2 inch (51 mm) diameter solid ball, and the discharge piping of each ejector or pump shall have a backwater valve and gate valve, and be not less than 3 inches (80 mm) in diameter.
[HCD 1 & HCD 2] The minimum size of any pump or any discharge pipe from a sump having a water closet connected thereto shall be not less than 2 inches (50 mm). 710.4 Discharge Line. The discharge line from such ejector, pump, or another mechanical device shall be of approved pressure rated material and be provided with an accessible backwater or swing check valve and gate or ball valve. Where the gravity drainage line to which such discharge line connects is horizontal, the method of connection shall be from the top through a wye branch fitting. The gate or ball valve shall be located on the discharge side of the backwater or check valve.
Gate or ball valves, where installed in drainage piping, shall be fullway type with working parts of corrosion-resistant metal. Sizes 4 inches (100 mm) or more in diameter shall have cast-iron bodies and sizes less than 4 inches (100 mm), cast-iron or copper alloy bodies. 710.5 Size of Building Drains and Sewers. Building drains or building sewers receiving a discharge from a pump or ejector shall be adequately sized to prevent overloading. Two fixture units shall be allowed for each gallon per minute (L/s) of flow. 710.6 Backwater Valves. Backwater valves, gate valves, fullway ball valves, unions, motors, compressors, air tanks, and other mechanical devices required by this section shall be located where they will be accessible for inspection and repair and, unless continuously exposed, shall be enclosed in a masonry pit fitted with an adequately sized removable
cover.
Backwater valves shall comply with ASME A112.14.1 or IAPMO IGC 305, and have bodies of cast-iron, plastic, copper alloy, or other approved materials; shall have noncorrosive bearings, seats, and self-aligning discs; and shall be constructed to ensure a positive mechanical seal.
CPC § 710.5 High relevance — show source text
Gate or ball valves, where installed in drainage piping, shall be fullway type with working parts of corrosion-resistant metal. Sizes 4 inches (100 mm) or more in diameter shall have cast-iron bodies and sizes less than 4 inches (100 mm), cast-iron or copper alloy bodies. 710.5 Size of Building Drains and Sewers. Building drains or building sewers receiving a discharge from a pump or ejector shall be adequately sized to prevent overloading. Two fixture units shall be allowed for each gallon per minute (L/s) of flow. 710.6 Backwater Valves. Backwater valves, gate valves, fullway ball valves, unions, motors, compressors, air tanks, and other mechanical devices required by this section shall be located where they will be accessible for inspection and repair and, unless continuously exposed, shall be enclosed in a masonry pit fitted with an adequately sized removable
cover.
Backwater valves shall comply with ASME A112.14.1 or IAPMO IGC 305, and have bodies of cast-iron, plastic, copper alloy, or other approved materials; shall have noncorrosive bearings, seats, and self-aligning discs; and shall be constructed to ensure a positive mechanical seal. Such backwater valves shall remain open during periods of low flows to avoid screening of solids and shall not restrict capacities or cause excessive turbulence during peak loads. Unless otherwise listed, valve access covers shall be bolted type with gasket, and each valve shall bear the manufacturer’s name cast into the body and the cover. 710.7 Drainage and Venting Systems. The drainage and venting systems, in connection with fixtures, sumps, receiving tanks, and mechanical waste-lifting devices shall be installed under the same requirements as provided for in this code for gravity systems. 710.8 Sump and Receiving Tank Construction. Sumps and receiving tanks shall be watertight and shall be constructed of concrete, metal, or other approved materials. Where constructed of poured concrete, the walls and bottom shall be adequately reinforced and designed to recognized acceptable standards. Metal sumps or tanks shall be of such
thickness as to serve their intended purpose and shall be treated internally and externally to resist corrosion.
710.9 Alarm. Such sumps and receiving tanks shall be automatically discharged and, wherein a “public use” occupancy, shall be provided with dual pumps or ejectors arranged to function alternately in normal use and independently. Such pumps shall be capable of running continuously in case of overload or mechanical failure of one of the pumps or ejectors. The pumps shall have an audio and visual alarm, readily accessible, that signals pump failure or an overload condition. The lowest inlet shall have a clearance of not less than 2 inches (51 mm) from the high-water or “starting” level of the sump. 710.10 Sump and Receiving Tank Covers and Vents. Sumps and receiving tanks shall be provided with substantial covers having a bolt-and-gasket-type manhole or equivalent opening to permit access for inspection, repairs, and cleaning. The top shall be provided with a vent pipe that shall extend separately through the roof or, where permitted, be combined with other vent pipes. Such vent shall be large enough to maintain atmospheric pressure within the sump under normal operating conditions and, in no case, shall be less in size than that required by Table 703.2 for the number and type of fixtures discharging into the sump, nor less than 1 [1] ⁄ 2 inches (40 mm) in diameter.
CPC § 707.12 High relevance — show source text
707.12 Countersunk Cleanout Plugs. Countersunk cleanout plugs shall be installed where raised heads cause a hazard.
707.13 Hubless Blind Plugs. Where a hubless blind plug is used for a required cleanout, the complete coupling and plug shall be accessible for removal or replacement. 707.14 Trap Arms. Cleanouts for trap arms shall be installed in accordance with Section 1002.3.
708.0 Grade of Horizontal Drainage Piping. 708.1 General. Building drain and other horizontal drainage piping shall be run in practical alignment and a uniform slope of not less than [1] ⁄ 4 inch per foot (20.8 mm/m) or 2 percent toward the point of disposal.
Where it is impractical due to the depth of the street sewer, structural features, or to the arrangement of a building or structure to obtain a slope of [1] ⁄ 4 inch per foot (20.8 mm/m) or 2 percent, building drain piping 4 inches (100 mm) or larger in diameter shall be permitted to have a slope of not less than [1] ⁄ 8 inch per foot (10.4 mm/m) or 1 percent, when first approved by the Authority Having Jurisdiction.
709.0 Gravity Drainage Required. 709.1 General. Where practicable, plumbing fixtures shall be drained to the public sewer or private sewage disposal system by gravity.
710.0 Drainage of Fixtures Located Below the Next Upstream Manhole or Below the Main Sewer Level.
710.1 Backflow Protection. Fixtures installed on a floor level that is lower than the next upstream manhole cover of the public, or private sewer shall be protected from backflow of sewage by installing an approved type of backwater valve. Fixtures on such floor level that are not below the next upstream manhole cover shall not be required to be protected by a backwater valve. Fixtures on floor levels above such elevation shall not discharge through the backwater valve. Cleanouts for drains that pass through a backwater valve shall be clearly identified with a permanent label stating “backwater valve downstream.”
710.2 Sewage Discharge. Drainage piping serving fixtures that are located below the crown level of the main sewer shall discharge into an approved watertight sump or receiving tank, so located as to receive the sewage or wastes by gravity. From such sump or receiving tank, the sewage or other liquid wastes shall be lifted and discharged into the building drain or building sewer by approved ejectors, pumps, or other equally efficient approved mechanical devices. 710.3 Sewage Ejector and Pumps. A sewage ejector or sewage pump receiving the discharge of water closets or urinals:
(1) Shall have a discharge capacity of not less than 20 gpm (1.26 L/s).
(2) In single dwelling units, the ejector or pump shall be capable of passing an 1 [1] ⁄ 2 inch (38 mm) diameter solid ball, and the discharge piping of each ejector or pump
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), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
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shall have a backwater valve and gate valve, and be not less than 2 inches (50 mm) in diameter.
CPC § 710.8 High relevance — show source text
710.8 Sump and Receiving Tank Construction. Sumps and receiving tanks shall be watertight and shall be constructed of concrete, metal, or other approved materials. Where constructed of poured concrete, the walls and bottom shall be adequately reinforced and designed to recognized acceptable standards. Metal sumps or tanks shall be of such
thickness as to serve their intended purpose and shall be treated internally and externally to resist corrosion.
710.9 Alarm. Such sumps and receiving tanks shall be automatically discharged and, wherein a “public use” occupancy, shall be provided with dual pumps or ejectors arranged to function alternately in normal use and independently. Such pumps shall be capable of running continuously in case of overload or mechanical failure of one of the pumps or ejectors. The pumps shall have an audio and visual alarm, readily accessible, that signals pump failure or an overload condition. The lowest inlet shall have a clearance of not less than 2 inches (51 mm) from the high-water or “starting” level of the sump. 710.10 Sump and Receiving Tank Covers and Vents. Sumps and receiving tanks shall be provided with substantial covers having a bolt-and-gasket-type manhole or equivalent opening to permit access for inspection, repairs, and cleaning. The top shall be provided with a vent pipe that shall extend separately through the roof or, where permitted, be combined with other vent pipes. Such vent shall be large enough to maintain atmospheric pressure within the sump under normal operating conditions and, in no case, shall be less in size than that required by Table 703.2 for the number and type of fixtures discharging into the sump, nor less than 1 [1] ⁄ 2 inches (40 mm) in diameter. Where the preceding requirements are met and the vent, after leaving the sump, is combined with vents from fixtures discharging into the sump, the size of the combined vent need not exceed that required for the total number of fixtures discharging into the sump. No vent from an air-operating sewage ejector shall combine with other vents. 710.11 Air Tanks. Air tanks shall be so proportioned as to be of equal cubical capacity to the ejectors connected in addition to that in which there shall be maintained an air pressure of not less than 2 pounds per foot (lb/ft) (3 kg/m) of height the sewage is to be raised. No water-operated ejectors shall be permitted. 710.12 Grinder Pump Ejector. Grinder pumps shall be permitted to be used. 710.12.1 Discharge Piping. The discharge piping shall be sized in accordance with the manufacturer’s installation instructions and shall be not less than 1 [1] ⁄ 4 inches (32 mm) in diameter. A check valve and fullwaytype shutoff valve shall be located on the discharge line. 710.13 Macerating Toilet Systems and Pumped Waste Systems. Fixtures shall be permitted to discharge to a macerating toilet system, or pumped waste system shall be permitted as an alternate to a sewage pump system where approved by the Authority Having Jurisdiction. Such systems shall comply with ASME A112.3.4/CSA B45.9 and shall be installed in accordance with the manufacturer’s installation
instructions.
CPC § 104.0 High relevance — show source text
Rectangular scuppers . . . . . . . . . . . . . . . . . . . .D 104.0
Sewage ejectors or pumps . . . . . . . . . . . . . . . . . .710.3
Sump pump . . . . . . . . . . . . . . . . . . . . . . . . . . . .1101.6.2
Water heaters . . . . . . . . . . . . . . . . . . .501.1, Table 501.1(1)
CAST-IRON PIPE
Approved standards . . . . . . . . . . . . . . . . . . . . . .301.2.4
Discharge line from ejectors . . . . . . . . . . . . . . . . .710.4
Drainage piping . . . . . . . . . . . . . . . . . . . . . . . . . . .701.2
Fittings . . . . . . . . . . . . . . . . . .301.2.3, 604.6, 1208.5.9.5
Flanges . . . . . . . . . . . . . . . . . . . . . . . . . . . .1208.5.11.1
Joining . . . . . . . . . . . . . . . . . . . . . . . . . .705.2, 705.10.1
Prohibited use . . . . . . . . . . . . . . . . . . . .316.1, 1208.5.2
CAULKED JOINTS . . . . . . . . . . . . . . . . . . . . . . . . . .705.2.1
CAULKING FERRULES . . . . . . . . . . . . . .701.6, Table 701.6
CERTIFICATION
Backflow assembly testers . . . . . . . . . . . . .205.0, 603.2
Medical gas or medical
vacuum installers . . . . . . . . . . . . . . . . . . . . . .1323.10
Medical gas or medical
vacuum systems . . . . . . . . . . . . . . . . . . . . . . .1306.0
Pipe welder, definition . . . . . . . . . . . . . . . . . . . . . .225.0
Residential fire sprinklers installers . . . . . . . . . . . .612.1
CESSPOOL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .H 801.1
Abandoned . . . . . . . . . . . . . . . . . . . . . . .722.0, H 1101.0
Connections to sewer prohibited . . . . . . . . . . . . . .714.3
Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .205.0
CHECK VALVES
In drainage systems . . . . . . . . . . . . . . .710.4, 710.12.1,
710.13.2, 1004.2
CPC § 710.0 High relevance — show source text
710.0 Drainage of Fixtures Located Below the Next Upstream Manhole or Below the Main
Sewer Level . . . . . . . . . . . . . . . . .173
710.1 Backflow Protection . . . . . . . . . . .173
710.2 Sewage Discharge . . . . . . . . . . . .173
710.3 Sewage Ejector and Pumps . . . . .173
710.4 Discharge Line . . . . . . . . . . . . . . .174
710.5 Size of Building Drains and Sewers . . . . . . . . . . . . . . . . . . . . .174
710.6 Backwater Valves . . . . . . . . . . . . .174
710.7 Drainage and Venting Systems . . .174
710.8 Sump and Receiving Tank Construction . . . . . . . . . . . . . . . . .174
710.9 Alarm . . . . . . . . . . . . . . . . . . . . . .174
710.10 Sump and Receiving Tank Covers and Vents . . . . . . . . . . . . .174
710.11 Air Tanks . . . . . . . . . . . . . . . . . . .174
710.12 Grinder Pump Ejector . . . . . . . . . .174
710.13 Macerating Toilet Systems and Pumped Waste Systems . . . .174
711.0 Suds Relief . . . . . . . . . . . . . . . . . .175
711.1 General . . . . . . . . . . . . . . . . . . . . .175
712.0 Testing . . . . . . . . . . . . . . . . . . . . .175
712.1 Media . . . . . . . . . . . . . . . . . . . . . .175
712.2 Water Test . . . . . . . . . . . . . . . . . .175
712.3 Air Test . . . . . . . . . . . . . . . . . . . . .175
PART II Building Sewers . . . . . . . . . . . . .175
713.0 Sewer Required . . . . . . . . . . . . . .175
713.1 Where Required . . . . . . . . . . . . . .175
713.2 Private Sewage Disposal System . . . . . . . . . . . . . . . . . . . . .175
713.3 Public Sewer . . . . . . . . . . . . . . . . .175
713.4 Public Sewer Availability . . . . . . .175
713.5 Permit . . . . . . . . . . . . . . . . . . . . . .175
713.6 Lot . . . . . . . . . . . . . . . . . . . . . . . . .175
713.7 Installation . . . . . . . . . . . . . . . . . .175
714.0 Damage to Public Sewer or Private Sewage Disposal System . . . . . . . . . . . . . . . . . . . . .175
714.1 Unlawful Practices . . . . . . . . . . . .175
CPC § 710.11 High relevance — show source text
Where the preceding requirements are met and the vent, after leaving the sump, is combined with vents from fixtures discharging into the sump, the size of the combined vent need not exceed that required for the total number of fixtures discharging into the sump. No vent from an air-operating sewage ejector shall combine with other vents. 710.11 Air Tanks. Air tanks shall be so proportioned as to be of equal cubical capacity to the ejectors connected in addition to that in which there shall be maintained an air pressure of not less than 2 pounds per foot (lb/ft) (3 kg/m) of height the sewage is to be raised. No water-operated ejectors shall be permitted. 710.12 Grinder Pump Ejector. Grinder pumps shall be permitted to be used. 710.12.1 Discharge Piping. The discharge piping shall be sized in accordance with the manufacturer’s installation instructions and shall be not less than 1 [1] ⁄ 4 inches (32 mm) in diameter. A check valve and fullwaytype shutoff valve shall be located on the discharge line. 710.13 Macerating Toilet Systems and Pumped Waste Systems. Fixtures shall be permitted to discharge to a macerating toilet system, or pumped waste system shall be permitted as an alternate to a sewage pump system where approved by the Authority Having Jurisdiction. Such systems shall comply with ASME A112.3.4/CSA B45.9 and shall be installed in accordance with the manufacturer’s installation
instructions.
710.13.1 Sumps. The sump shall be watertight and gastight. 710.13.2 Discharge Piping. The discharge piping shall be sized in accordance with manufacturer’s instructions and shall be not less than [3] ⁄ 4 of an inch (20 mm) in diameter. The developed length of the discharge piping shall not exceed the manufacturer’s instructions. A check
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valve and fullway-type shutoff valve shall be located within the discharge line or internally within the device.
710.13.3 Venting. The plumbing fixtures that discharge into the macerating device shall be vented in accordance with this code. The sump shall be vented in accordance with the manufacturer’s instructions, and such vent shall be permitted to connect to the fixture venting.
711.0 Suds Relief.
711.1 General. Drainage connections shall not be made into a drainage piping system within 8 feet (2438 mm) of a vertical to horizontal change of direction of a stack containing suds-producing fixtures. Bathtubs, laundries, washing machine standpipes, kitchen sinks, and dishwashers shall be considered suds-producing fixtures. Where parallel vent stacks are required, they shall connect to the drainage stack at a point 8 feet (2438 mm) above the lowest point of the drainage stack.
Exceptions:
(1) Single-family residences.
(2) Stacks receiving the discharge from less than three stories of plumbing fixtures.
712.0 Testing.
CPC § 710.2 High relevance — show source text
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INDEX
Pump connection permitted . . . . .710.2 – 710.5, 710.9,
805.1, 1101.6.2, 1101.7
Pump discharges, conversion
to fixture units . . . . . . . . . . . . . . . . . . . . .702.3, 710.5
Sewage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .710.2
Sizing, sewage
ejector and pumps . . . . . . . . . . . . . . . . . . . . . . .710.3
Storm drainage . . . . . . . . . . . .1101.6.2, 1101.6.3, 1101.7,
1101.10, 1101.11, 1101.14
Vents . . . . . . . . . . . . . . . . . . . . .710.7, 710.10, 710.13.3,
810.1, Table 810.1
Water supply inlets . . . . . . . . . . . . . . . . . . . . . . .603.5.5
SUPPLY, WATER
Fittings, fixtures . . . . . . . . . . . . . . . . . . . . . . . . . . .402.7
Fixture, definition . . . . . . . . . . . . . . . . . . . . . . . . . .208.0
Fixture units . . . . . . . . . . . . . . . . . . .610.3, Table 610.3,
610.7 – 610.10, Table 610.10,
Table A 103.1, C 303.2,
C 501.5, E 302.1, E 302.2,
E 302.2.2, L 402.3.1
Hot water . . . . . . . . . . . . . . . . . .601.2.1, 602.1, 603.4.5,
603.5.10, 608.7, 609.1,
609.4, 610.3, Table 610.3,
610.12.1, 610.12.2,
Table A 103.1, A 105.3,
Table C 303.2, L 502.5,
L 502.7, L 502.7.3
Materials . . . . . . . . . . . . . . . . . . . . .604.0, Table 604.1,
1503.9.2 – 1503.9.4,
1505.7, 1506.7,
1602.7, K 103.4
Nonpotable water . . . . . . . . . . . .601.3, 603.5.11, 1506.6
Pipe, size of . . . . . . . . . . . . . . . . . . .610.0, Table 610.3,
Table 610.4, Table A 103.1,
CPC § 0.95 High relevance — show source text
The sump shall be not less than 15 inches (381 mm) in diameter, 18 inches (457 mm) in depth, and provided with a fitted cover. The sump pump shall have an adequate capacity to discharge water coming into the sump as it accumulates to the required discharge point, and the capacity of the pump shall be not less than 15 gallons per minute (gpm) (0.95 L/s). The discharge piping from the sump pump shall be not less than 1 [1] ⁄ 2 inches (40 mm) in diameter and have a union or other approved quick-disconnect assembly to make the pump accessible for servicing. 1101.6.3 Splash Blocks. For separate dwellings not serving continuously flowing springs or groundwater, the sump discharge pipe shall be permitted to discharge onto a concrete splash block with a minimum length of 24 inches (610 mm). This pipe shall be within 4 inches (102 mm) of the splash block and positioned to direct the flow parallel to the recessed line of the splash block.
1101.6.4 Backwater Valve. Subsoil drains subject to backflow where discharging into a storm drain shall be provided with a backwater valve in the drain line so located as to be accessible for inspection and maintenance. 1101.6.5 Open Area. Nothing in Section 1101.6 shall prevent drains that serve either subsoil drains or areaways of a detached building from discharging to a properly graded open area, provided that:
(1) They do not serve continuously flowing springs or groundwater.
(2) The point of discharge is not less than 10 feet (3048 mm) from a property line.
(3) It is impracticable to discharge such drains to a storm drain, to an approved water course, to the front street curb or gutter, or to an alley. 1101.7 Building Subdrains. Building subdrains located below the public sewer level shall discharge into a sump or receiving tank, the contents of which shall be automatically lifted and discharged into the drainage system as required for building sumps. 1101.8 Areaway Drains. Open subsurface space adjacent to a building, serving as an entrance to the basement or cellar of a building, shall be provided with a drain or drains. The areaway drains shall be not less than 2 inches (50 mm) in diameter for areaways at a maximum of 100 square feet (9.29 m [2] ) in area, and shall be discharged in the manner provided for subsoil drains not serving continuously flowing springs or groundwater (see Section 1101.6.1). Areaways exceeding 100 square feet (9.29 m [2] ) shall not drain into subsoil drains.
The drains for areaways exceeding 100 square feet (9.29 m [2] ) shall be sized in accordance with Table 1103.2.
CPC § 1503.4 High relevance — show source text
Table 1503.4
Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1504.1
SUBSURFACE
IRRIGATION FIELDS . . . . . . . . . . . . . . . .221.0, 1503.2.1,
1504.2 – 1504.4, 1504.5,
1504.5.2
SUDS RELIEF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .711.0
SUMPS
Boiler room, installation . . . . . . . . . . . . . . .810.1, 810.3
Building, backwater
devices . . . . . . . . . . . . . . .710.1, 710.3, 710.4, 710.6
Building drainage
systems below sewer level . . . . . . . . . . . . . . . . . . .710.2
Condensers . . . . . . . . . . . . . . . . . . . .810.0, Table 810.1
Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . .810.2
Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .221.0
Macerating toilet systems . . . . . . . . . . . . . . . . .710.13.1
580 2025 CALIFORNIA PLUMBING CODE
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
INDEX
Pump connection permitted . . . . .710.2 – 710.5, 710.9,
805.1, 1101.6.2, 1101.7
Pump discharges, conversion
to fixture units . . . . . . . . . . . . . . . . . . . . .702.3, 710.5
Sewage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .710.2
Sizing, sewage
ejector and pumps . . . . . . . . . . . . . . . . . . . . . . .710.3
Storm drainage . . . . . . . . . . . .1101.6.2, 1101.6.3, 1101.7,
1101.10, 1101.11, 1101.14
Vents . . . . . . . . . . . . . . . . . . . . .710.7, 710.10, 710.13.3,
810.1, Table 810.1
Water supply inlets . . . . . . . . . . . . . . . . . . . . . . .603.5.5
SUPPLY, WATER
Fittings, fixtures . . . . . . . . . . . . . . . . . . . . . . . . . . .402.7
CPC § 707.2 High relevance — show source text
Table 707.2 Cleanout Materials for Drain, Waste, and Vent . . . . . . . . . . . . . .172
707.3 Watertight and Gastight . . . . . . . .172
707.4 Location . . . . . . . . . . . . . . . . . . . .172
707.5 Cleaning . . . . . . . . . . . . . . . . . . . .173
707.6 Extension . . . . . . . . . . . . . . . . . . .173
707.7 Interceptor . . . . . . . . . . . . . . . . . .173
707.8 Access . . . . . . . . . . . . . . . . . . . . .173
707.9 Clearance . . . . . . . . . . . . . . . . . . .173
707.10 Fittings . . . . . . . . . . . . . . . . . . . . .173
707.11 Pressure Drainage Systems . . . . .173
707.12 Countersunk Cleanout Plugs . . . .173
707.13 Hubless Blind Plugs . . . . . . . . . . .173
707.14 Trap Arms . . . . . . . . . . . . . . . . . . .173
708.0 Grade of Horizontal Drainage Piping . . . . . . . . . . . . . . . . . . . . . .173
708.1 General . . . . . . . . . . . . . . . . . . . . .173
709.0 Gravity Drainage Required . . . . . .173
709.1 General . . . . . . . . . . . . . . . . . . . . .173
710.0 Drainage of Fixtures Located Below the Next Upstream Manhole or Below the Main
Sewer Level . . . . . . . . . . . . . . . . .173
710.1 Backflow Protection . . . . . . . . . . .173
710.2 Sewage Discharge . . . . . . . . . . . .173
710.3 Sewage Ejector and Pumps . . . . .173
710.4 Discharge Line . . . . . . . . . . . . . . .174
710.5 Size of Building Drains and Sewers . . . . . . . . . . . . . . . . . . . . .174
710.6 Backwater Valves . . . . . . . . . . . . .174
710.7 Drainage and Venting Systems . . .174
710.8 Sump and Receiving Tank Construction . . . . . . . . . . . . . . . . .174
710.9 Alarm . . . . . . . . . . . . . . . . . . . . . .174
710.10 Sump and Receiving Tank Covers and Vents . . . . . . . . . . . . .174
710.11 Air Tanks . . . . . . . . . . . . . . . . . . .174
710.12 Grinder Pump Ejector . . . . . . . . . .174
710.13 Macerating Toilet Systems and Pumped Waste Systems . . . .174
711.0 Suds Relief . . . . . . . . . . . . . . . . . .175
CPC § 1503.8. Medium relevance — show source text
(1) The discharge capacity of a gray water system shall be determined by Section 1503.8. Complex systems have a discharge capacity over 250 gallons (947 L) per day.
(2) Complex systems shall require a construction permit, unless exempted from a construction permit by the Enforcing Agency. The Enforcing Agency shall con- sult with the water purveyor for any public water sys- tem (as defined in Health and Safety Code, Section 116275) providing drinking water to the dwelling or non-residential structure before allowing an exemp- tion from a construction permit. 1503.2 System Requirements. Gray water shall be permitted to be diverted away from a sewer or private sewage disposal system, and discharge to a subsurface irrigation or subsoil irrigation system , or disposal field . The gray water shall be permitted to discharge to a mulch basin residential occupancies . Gray water shall not be used to irrigate root crops or food crops intended for human consumption that comes in contact with soil.
1503.2.1 Surge Capacity. Gray water systems shall be designed to have the capacity to accommodate peak flow rates and distribute the total amount of estimated gray water on a daily basis to a subsurface irrigation field, subsoil irrigation field , disposal field, or mulch
basin without surfacing, ponding, or runoff. A surge tank is required for systems that are unable to accommodate peak flow rates and distribute the total amount of gray water by gravity drainage. The water discharge for gray water systems shall be determined in accordance with Section 1503.8.1 or Section 1503.8.2.
Exception: It is not the intent of this section to require that all gray water must be handled by an irrigation field or disposal field. It is acceptable for excess gray water to be diverted to the building sewer through a diverter valve or overflow drain as permitted in this chapter. 1503.2.2 Diversion. The gray water system shall connect to the sanitary drainage system downstream of fixture traps and vent connections through an approved diverter valve. The diverter valve shall be installed in a readily accessible location and clearly indicate the direction of flow.
Exception: [HCD 1] A clothes washer system in com- pliance with Section 1503.1.1. 1503.2.3 Backwater Valves. Gray water drains subject to backflow shall be provided with a backwater valve at the point of connection to the building sewer system, so located as to be accessible for inspection and maintenance. 1503.3 Connections to Potable and Reclaimed (Recy- cled) Water Systems. Gray water systems shall have no direct connection to a potable water supply, on-site treated nonpotable gray water supply, or reclaimed (recycled) water sup- ply systems.
Exceptions:
(1) Potable water, on-site treated nonpotable gray water, reclaimed (recycled) water , or rainwater is permitted to be used as makeup water for a non-pressurized storage tank provided the connection is protected by an air gap in accordance with this code.
Frequently asked questions
Do I always need a sump if a fixture is below the public sewer manhole?
Yes — fixtures located below the crown of the main sewer must discharge into a watertight sump or receiving tank, and the contents must be lifted by an approved ejector or pump. § 710.2.
What minimum pump size is required when the ejector serves a water closet?
Minimum discharge capacity is 20 gpm (1.26 L/s) for ejectors receiving the discharge of water closets or urinals. § 710.3 (1).
What are the backwater valve requirements?
Backwater valves must be accessible for inspection/repair, comply with ASME A112.14.1 or IAPMO IGC 305, and be constructed of approved materials with non‑corrosive bearings and positive mechanical seal. § 710.6.
How must the sump be constructed and vented?
Sumps must be watertight (concrete, metal, or approved material); provide a gasketed manhole/cover for access and a vent sized per Table 703.2 but not less than 1‑1/2 in (40 mm). § 710.8 / § 710.10.
Are macerating toilets or grinder pumps allowed instead of a sewage ejector?
Yes — grinder pumps are permitted (§ 710.12) and macerating/pumped waste systems are allowed where approved and when installed per standards/manufacturer instructions (§ 710.13).
More in California Plumbing Code
- Administration
- Definitions
- General Regulations
- Plumbing Fixtures and Fixture Fittings
- Water Heaters
- Water Supply and Distribution
- Sanitary Drainage (Drain, Waste, and Vent)
- Indirect Wastes
- Vents
- Traps and Interceptors
- Storm Drainage
- Fuel Gas Piping
- Health Care Facilities — Medical Gas and Medical Vacuum Systems
- Alternate Water Sources and Nonpotable Rainwater Catchment Systems
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