Storm Drainage

Grounded in the retrieved California Plumbing Code — click a citation to read the verbatim passage:

• CPC § 1103.0 High relevance — show source text

  1103.0 Size of Leaders, Conductors, and Storm Drains.

  1103.1 Vertical Conductors and Leaders. Vertical conductors and leaders shall be sized by the maximum projected roof area and Table 1103.1.

  1103.2 Size of Horizontal Storm Drains and Sewers. The size of building storm drains, or building storm sewers or their horizontal branches shall be based on the maximum projected roof or paved area to be handled and Table 1103.2.

  1103.3 Size of Roof Gutters. The size of semi-circular gutters shall be based on the maximum projected roof area and Table 1103.3.

  1103.4 Side Walls Draining onto a Roof. Where vertical walls project above a roof to permit storm water to drain into the roof area below, the adjacent roof area shall be permitted to be computed from Table 1103.1 as follows:

  (1) For one wall – add 50 percent of the wall area to the roof area figures.

  (2) For two adjacent walls of equal height – add 35 percent of the total wall areas.

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  STORM DRAINAGE

  Col1	Col2	TABLE 1103.1 SIZING ROOF DRAINS, LEADERS, AND VERTICAL RAINWATER PIPING2, 3	Col4	Col5	Col6	Col7	Col8	Col9	Col10	Col11	Col12	Col13	Col14
  SIZE OF DRAIN, LEADER, OR PIPE	FLOW	MAXIMUM ALLOWABLE HORIZONTAL PROJECTED ROOF AREAS AT VARIOUS RAINFALL RATES (square feet)	MAXIMUM ALLOWABLE HORIZONTAL PROJECTED ROOF AREAS AT VARIOUS RAINFALL RATES (square feet)	MAXIMUM ALLOWABLE HORIZONTAL PROJECTED ROOF AREAS AT VARIOUS RAINFALL RATES (square feet)	MAXIMUM ALLOWABLE HORIZONTAL PROJECTED ROOF AREAS AT VARIOUS RAINFALL RATES (square feet)	MAXIMUM ALLOWABLE HORIZONTAL PROJECTED ROOF AREAS AT VARIOUS RAINFALL RATES (square feet)	MAXIMUM ALLOWABLE HORIZONTAL PROJECTED ROOF AREAS AT VARIOUS RAINFALL RATES (square feet)	MAXIMUM ALLOWABLE HORIZONTAL PROJECTED ROOF AREAS AT VARIOUS RAINFALL RATES (square feet)	MAXIMUM ALLOWABLE HORIZONTAL PROJECTED ROOF AREAS AT VARIOUS RAINFALL RATES (square feet)	MAXIMUM ALLOWABLE HORIZONTAL PROJECTED ROOF AREAS AT VARIOUS RAINFALL RATES (square feet)	MAXIMUM ALLOWABLE HORIZONTAL PROJECTED ROOF AREAS AT VARIOUS RAINFALL RATES (square feet)	MAXIMUM ALLOWABLE HORIZONTAL PROJECTED ROOF AREAS AT VARIOUS RAINFALL RATES (square feet)	**MAXIMUM

• CPC § 1101.16 High relevance — show source text

  1101.16 Leaders, Conductors, and Connections. Leaders or conductors shall not be used as soil, waste, or vent pipes nor shall soil, waste, or vent pipes be used as leaders or conductors.

  1101.16.1 Protection of Leaders. Leaders installed along alleyways, driveways, or other locations where exposed to damage shall be protected by metal guards, recessed into the wall, or constructed from the ferrous pipe. 1101.16.2 Combining Storm with Sanitary Drainage. The sanitary and storm drainage system of a building shall be entirely separate, except where a combined sewer is used, in which case the building storm drain shall be connected in the same horizontal plane through a single wye fitting to the combined building sewer not less than 10 feet (3048 mm) downstream from a soil stack.

  1102.0 Roof Drains.

  1102.1 Applications. Roof drains shall be constructed of aluminum, cast-iron, copper alloy of not more than 15 percent zinc, leaded nickel bronze, stainless steel, ABS, PVC, polypropylene, polyethylene, or nylon and shall comply with ASME A112.3.1 or ASME A112.6.4.

  1102.2 Dome Strainers Required. Roof drains shall have domed strainers.

  Exception: Roof drain strainers for use on sun decks, parking decks, and similar areas that are normally serviced and maintained, shall be permitted to be of the flat surface type. Such roof drain strainers shall be level with the deck.

  1102.3 Roof Drain Flashings. The connection between the roof and roof drains that pass through the roof and into the interior of the building shall be made watertight by the use of proper flashing material. 1102.3.1 Lead Flashing. Where lead flashing material is used, it shall be not less than 4 pounds per square foot (lb/ft [2] ) (19 kg/m [2] ). 1102.3.2 Copper Flashing. Where copper flashing material is used, it shall be not less than 12 ounces per square foot (oz/ft [2] ) (3.7 kg/m [2] ).

  1103.0 Size of Leaders, Conductors, and Storm Drains.

  1103.1 Vertical Conductors and Leaders. Vertical conductors and leaders shall be sized by the maximum projected roof area and Table 1103.1.

  1103.2 Size of Horizontal Storm Drains and Sewers. The size of building storm drains, or building storm sewers or their horizontal branches shall be based on the maximum projected roof or paved area to be handled and Table 1103.2.

  1103.3 Size of Roof Gutters. The size of semi-circular gutters shall be based on the maximum projected roof area and Table 1103.3.

  1103.4 Side Walls Draining onto a Roof. Where vertical walls project above a roof to permit storm water to drain into the roof area below, the adjacent roof area shall be permitted to be computed from Table 1103.1 as follows:

  (1) For one wall – add 50 percent of the wall area to the roof area figures.

  (2) For two adjacent walls of equal height – add 35 percent of the total wall areas.

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• CPC § 1101.1 High relevance — show source text

  1101.1 Applicability . . . . . . . . . . . . . . . . . .205

  1101.2 Where Required . . . . . . . . . . . . . .205

  1101.3 Storm Water Drainage to Sanitary Sewer Prohibited . . . . . .205

  1101.4 Material Uses . . . . . . . . . . . . . . . .205

  Table 1101.4.6 Materials for Subsoil Drainpipe and Fittings . . . . . . . . . . . . . . . . . .205

  1101.5 Expansion Joints Required . . . . . .205

  1101.6 Subsoil Drains . . . . . . . . . . . . . . .205

  1101.7 Building Subdrains . . . . . . . . . . . .206

  1101.8 Areaway Drains . . . . . . . . . . . . . .206

  1101.9 Window Areaway Drains . . . . . . .206

  1101.10 Filling Stations and Motor Vehicle Washing Establishments . . . . . . . . . . . . . . .206

  1101.11 Paved Areas . . . . . . . . . . . . . . . . .206

  1101.12 Roof Drainage . . . . . . . . . . . . . . .206

  1101.13 Cleanouts . . . . . . . . . . . . . . . . . . .207

  1101.14 Rainwater Sumps . . . . . . . . . . . . .207

  1101.15 Traps on Storm Drains and Leaders . . . . . . . . . . . . . . . . . . . . .207

  1101.16 Leaders, Conductors, and

  Connections . . . . . . . . . . . . . . . . .207

  1102.0 Roof Drains . . . . . . . . . . . . . . . . . .207

  1102.1 Applications . . . . . . . . . . . . . . . . .207

  1102.2 Dome Strainers Required . . . . . . .207

  1102.3 Roof Drain Flashings . . . . . . . . . .207

  1103.0 Size of Leaders, Conductors,

  and Storm Drains . . . . . . . . . . . . .207

  1103.1 Vertical Conductors and

  Leaders . . . . . . . . . . . . . . . . . . . . .207

  1103.2 Size of Horizontal Storm

  Drains and Sewers . . . . . . . . . . . .207

  1103.3 Size of Roof Gutters . . . . . . . . . . .207

  1103.4 Side Walls Draining onto a Roof . . . . . . . . . . . . . . . . . .207

  Table 1103.1 Sizing Roof Drains, Leaders, and Vertical Rainwater Piping . . .208

  1104.0 Values for Continuous Flow . . . . .208

  1104.1 General . . . . . . . . . . . . . . . . . . . . .208

  1105.0 Controlled-Flow Roof

  Drainage . . . . . . . . . . . . . . . . . . . .208

• CPC § 1101.12.2.2 High relevance — show source text

  1101.12.2.2 Secondary Roof Drain. Secondary roof drains shall be provided. The secondary roof drains shall be located not less than 2 inches (51 mm) above the roof surface. The maximum height of the roof drains shall be a height to prevent the depth of ponding water from exceeding that for which the roof was designed as determined by Section 1101.12.1. The secondary roof drains shall connect to a piping system in accordance with Section 1101.12.2.2.1 or Section 1101.12.2.2.2.

  1101.12.2.2.1 Separate Piping System. The secondary roof drainage system shall be a

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  STORM DRAINAGE

  separate system of piping, independent of the primary roof drainage system. The discharge shall be above grade, in a location observable by the building occupants or maintenance personnel. Secondary roof drain systems shall be sized in accordance with Section 1101.12.1

  based on the rainfall rate for which the primary system is sized. 1101.12.2.2.2 Combined System. The secondary roof drains shall connect to the vertical piping of the primary storm drainage conductor downstream of the last horizontal offset located below the roof. The primary storm drainage system shall connect to the building storm water that connects to an underground public storm sewer. The combined secondary and primary roof drain systems shall be sized in accordance with Section 1103.0 based on double the rain fall rate for the local area.

  1101.13 Cleanouts. Cleanouts for building storm drains shall comply with the requirements of Section 719.0 of this code.

  1101.13.1 Rain Leaders and Conductors. Rain leaders and conductors connected to a building storm sewer shall have a cleanout installed at the base of the

  leader or conductor before it connects to the horizontal

  drain.

  1101.14 Rainwater Sumps. Rainwater sumps serving “public use” occupancy buildings shall be provided with dual pumps arranged to function alternately in the case of overload or mechanical failure. Pumps rated 600 V or less shall comply with UL 778 and shall be installed in accordance with the manufacturer’s installation instructions.

  1101.15 Traps on Storm Drains and Leaders. Leaders and storm drains, where connected to a combined sewer, shall be trapped. Floor and area drains connected to a storm drain shall be trapped.

  Exception: Traps shall not be required where roof drains, rain leaders, and other inlets are at locations permitted under Section 906.0, Vent Termination.

  1101.15.1 Where Not Required. No trap shall be required for leaders or conductors that are connected to a sewer carrying storm water exclusively. 1101.15.2 Trap Size. Traps, where installed for individual conductors, shall be the same size as the horizontal drain to which they are connected.

  1101.15.3 Method of Installation of Combined Sewer. Individual storm-water traps shall be installed on the stormwater drain branch serving each storm-water inlet, or a single trap shall be installed in the main storm drain just before its connection with the combined building sewer. Such traps shall be provided with an accessible cleanout on the outlet side of the trap.

• CPC § 1101.4.2.2 High relevance — show source text

  1101.4.2.2 [OSHPD 1, 2, 3, 4 & 5] ABS and PVC installations are not allowed.

  1101.4.3 Leaders. Leaders installed outside shall comply with the applicable standards referenced in Table 701.2 for aboveground drain, waste, and vent pipe; aluminum sheet metal; galvanized steel sheet metal; or copper sheet metal. 1101.4.4 Underground Building Storm Drains. Underground building storm drains shall comply with the applicable standards referenced in Table 701.2 for underground drain, waste, and vent pipe. 1101.4.5 Building Storm Sewers. Building storm sewers shall comply with the applicable standards referenced in Table 701.2 for building sewer pipe. 1101.4.6 Subsoil Drains. Subsoil drains shall be open jointed, perforated, or both and constructed of materials in conformance with Table 1101.4.6.

  TABLE 1101.4.6

  MATERIALS FOR SUBSOIL DRAINPIPE AND FITTINGS

  MATERIAL	REFERENCED STANDARD(S)
  PE	ASTM F667
  PVC	ASTM D2729
  Vitrified Clay (Extra strength)	ASTM C4, ASTM C700

  1101.5 Expansion Joints Required. Expansion joints or sleeves shall be provided where warranted by temperature variations or physical conditions. 1101.6 Subsoil Drains. Subsoil drains shall be provided around the perimeter of buildings having basements, cellars, crawl spaces, or floors below grade. Such subsoil drains shall be permitted to be positioned inside or outside of the footing, shall be of perforated or open-jointed approved drain tile or pipe, not less than 3 inches (80 mm) in diameter, and shall be laid in gravel, slag, crushed rock, approved [3] ⁄ 4 of an inch (19.1 mm) crushed, recycled glass aggregate, or other approved porous material with not less than 4 inches (102 mm) surrounding the pipe. Filter media shall be provided for exterior subsoil piping. Exception: [HCD 1 & HCD 2] Subsoil drains are mandatory only when required by the Authority Having Jurisdiction due to geological conditions.

  TABLE 1101.4.6

  MATERIALS FOR SUBSOIL DRAINPIPE AND FITTINGS

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  1101.6.1 Discharge. Subsoil drains shall be piped to a storm drain, to an approved water course, to the front street curb or gutter, to an alley, or the discharge from the subsoil drains shall be conveyed to the alley by a concrete gutter. Where a continuously flowing spring or groundwater is encountered, subsoil drains shall be piped to a storm drain or an approved water course. 1101.6.2 Sump. Where it is not possible to convey the drainage by gravity, subsoil drains shall discharge to an accessible sump provided with an approved automatic electric pump.

• CPC § 1101.11 High relevance — show source text

  1101.11 Paved Areas. Where the occupant creates surface water drainage, the sumps, gratings, or floor drains shall be piped to a storm drain or an approved water course. 1101.12 Roof Drainage. Roof drainage shall comply with Section 1101.12.1 and Section 1101.12.2.

  1101.12.1 Primary Roof Drainage. Roof areas of a building shall be drained by roof drains or gutters. The location and sizing of drains and gutters shall be coordinated with the structural design and pitch of the roof. Unless otherwise required by the Authority Having Jurisdiction, roof drains, gutters, vertical conductors or leaders, and horizontal storm drains for primary drainage shall be sized based on a storm of 60 minutes duration and 100 year return period. Refer to Table D 101.1 (in Appendix D) for 100 years, 60-minute storms at various locations. 1101.12.2 Secondary Drainage. Secondary (emergency) roof drainage shall be provided by one of the methods specified in Section 1101.12.2.1 or Section 1101.12.2.2.

  1101.12.2.1 Roof Scuppers or Open Side. Secondary roof drainage shall be provided by an opensided roof or scuppers where the roof perimeter construction extends above the roof in such a manner that water will be entrapped. An open-sided roof or scuppers shall be sized to prevent the depth of ponding water from exceeding that for which the roof was designed as determined by Section 1101.12.1. Scupper openings shall be not less than 4 inches (102 mm) high and have a width equal to the circumference of the roof drain required for the area served, sized in accordance with Table 1103.1.

  1101.12.2.2 Secondary Roof Drain. Secondary roof drains shall be provided. The secondary roof drains shall be located not less than 2 inches (51 mm) above the roof surface. The maximum height of the roof drains shall be a height to prevent the depth of ponding water from exceeding that for which the roof was designed as determined by Section 1101.12.1. The secondary roof drains shall connect to a piping system in accordance with Section 1101.12.2.2.1 or Section 1101.12.2.2.2.

  1101.12.2.2.1 Separate Piping System. The secondary roof drainage system shall be a

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  separate system of piping, independent of the primary roof drainage system. The discharge shall be above grade, in a location observable by the building occupants or maintenance personnel. Secondary roof drain systems shall be sized in accordance with Section 1101.12.1

  based on the rainfall rate for which the primary system is sized. 1101.12.2.2.2 Combined System. The secondary roof drains shall connect to the vertical piping of the primary storm drainage conductor downstream of the last horizontal offset located below the roof. The primary storm drainage system shall connect to the building storm water that connects to an underground public storm sewer. The combined secondary and primary roof drain systems shall be sized in accordance with Section 1103.0 based on double the rain fall rate for the local area.

• CPC § 408.8.3 High relevance — show source text

  Sheet . . . . . . . . . . . . . . . . . . . . . . .408.8.3, 701.5, 906.6

  Water supply . . . . . . . . . . . . . . . . . . . . . .604.2, 604.2.1

  LEADERS

  Cleanouts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1101.13

  Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .214.0

  Installed outside . . . . . . . . . . . . . . . . . . . . . . . . .1101.4.3

  Leaders, conductors, and connections . . . . . . . .1101.16 Roof drainage . . . . . . . . . . . . . . . . . . . . . . . . . . .1101.12 Size of leaders, conductors, and

  storm drains . . . . . . . . . . . . . . . . . . . . . . . . . . .1103.0

  Sizing roof drains, leaders, and vertical rainwater piping . . . . . . . . . . . . .Table 1103.1 Traps on storm drains and leaders . . . . . . . . . . .1101.15

  LIMITED-DENSITY OWNER-BUILT

  RURAL DWELLING

  Connections to plumbing system . . . . . . . . . . . . . .304.1

  Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .214.0

  Disposal of liquid waste . . . . . . . . . . . . . . . . . . . . .303.1 Water supply and flushing . . . . . . . . . . . . . . . . . . .601.2 LIQUEFIED PETROLEUM

  GAS (LP-GAS) . . . . . . . . . . . . . . . 214.0, 1202.1, 1208.4.1,

  1208.5.6.3, 1208.5.10.4,

  1212.11, E 401.2,

  E 403.1, E 403.10

  LIQUID WASTES . . . . . . . . . . . . . . . . .214.0, 303.0, L 302.0

  LISTED . . . . . . . . . . . . . . . . . . . . . . . .214.0, 301.2, 402.6.2,

  501.1

  LISTING AGENCY . . . . . . . . . . . . . . . . . . . . . . .214.0, 301.2

  LOCATION OF

  Backwater valves . . . . . . . . .710.1, 710.3, 710.4, 710.6,

  1006.0, 1101.6.4, 1503.2.3,

  1503.9.1, 1503.9.7

• CPC § 4.2.1 High relevance — show source text

  4|X|||X|X|||||X||X|X|X|X|||||||||| |1101.4.2.1||||X||||||||||||||||||||| |1101.4.2.2||||||||||X||X|X|X|X|||||||||| |1101.6_ Exception_||||X|X||||||||||||||||||||

  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.

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  CHAPTER 11

  STORM DRAINAGE

  1101.0 General.

  1101.1 Applicability. This chapter shall govern the materials, design, and installation of storm water drainage systems. 1101.2 Where Required. Roofs, paved areas, yards, courts, courtyards, vent shafts, light wells, or similar areas having rainwater, shall be drained into a separate storm sewer system, or into a combined sewer system where a separate storm sewer system is not available, or to some other place of disposal satisfactory to the Authority Having Jurisdiction. In the case of one- and two-family dwellings, storm water shall be permitted to be discharged on flat areas, such as streets or lawns, so long as the storm water shall flow away from the building and away from adjoining property, and shall not create a nuisance. 1101.3 Storm Water Drainage to Sanitary Sewer Pro- hibited. Storm water shall not be drained into sewers intended for sanitary drainage. 1101.4 Material Uses. Pipe, tube, and fittings conveying rainwater shall be of such materials and design as to perform their intended function to the satisfaction of the Authority Having Jurisdiction. Conductors within a vent or shaft shall be of cast-iron, galvanized steel, wrought iron, copper, copper alloy, lead, Schedule 40 ABS DWV, Schedule 40 PVC DWV, stainless steel 304 or 316L [stainless steel 304 pipe and fittings shall not be installed underground and shall be kept not less than 6 inches (152 mm) aboveground], or other approved materials, and changes in direction shall be in accordance with the requirements of Section 706.0. ABS and PVC DWV piping installations shall be installed in accordance with applicable standards referenced in Chapter 17 and the firestop protection requirements in the California Building Code . Except for individual single-family dwelling units, materials exposed within ducts or plenums shall have a flame-spread index of not more than 25 and a smoke-developed index of not more than 50, where tested in accordance with ASTM E84 or UL 723. Plastic piping installed in plenums shall be tested in accordance with all requirements of ASTM E84 or UL 723. Mounting methods, supports and sample sizes of materials for testing that are not specified in ASTM E84 or UL 723 shall be prohibited.

• CPC § 1103.1 High relevance — show source text

  (3) Not less than two drains shall be installed in roof areas of 10 000 square feet (929 m [2] ) or less, and not less than one additional drain shall be installed for each 10 000 square feet (929 m [2] ) of roof area exceeding 10 000 square feet (929 m [2] ). (4) Each roof drain shall have a precalibrated, fixed (nonadjustable), and proportional weir (notched) in a standing water collar inside the strainer. No mechanical devices or valves shall be permitted. (5) Pipe sizing shall be based on the pre-calibrated rate of flow (gpm) (L/s) of the pre-calibrated weir for the maximum allowable water depth, and Table 1103.1 and Table 1103.2.

  (6) The height of stones or other granular material above the waterproofed surface shall not be considered in water depth measurement, and the roof surface in the vicinity of the drain shall not be recessed to create a reservoir.

  (7) Roof design, where controlled-flow roof drainage is used, shall be such that the design roof live load is not less than 30 lb/ft [2] (146 kg/m [2] ) to provide a safety factor exceeding the 15 lb/ft [2] (73 kg/m [2] ) represented by the depth of water stored on the roof in accordance with Table 1105.1(1). (8) Scuppers shall be provided in parapet walls. The distance of scupper bottoms above the roof level at the drains shall not exceed the maximum distances specified in Table 1105.1(2).

  (9) Scupper openings shall be not less than 4 inches (102 mm) high and have a width equal to the circumference of

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  the roof drain required for the area served, sized in accordance with Table 1103.1.

  (10)Flashings shall extend above the top of the scuppers.

  (11)At a wall or parapet, 45 degree (0.79 rad) cants shall be installed.

  (12)Separate storm and sanitary drainage systems shall be provided within the building.

  (13)Calculations for the roof drainage system shall be submitted along with the plans to the Authority Having Jurisdiction for approval.

  TABLE 1105.1(1) CONTROLLED-FLOW MAXIMUM ROOF WATER DEPTH

  ROOF RISE* (inches)	MAXIMUM WATER DEPTH AT DRAIN (inches)
  Flat	3
  2	4
  4	5
  6	6

  For SI units: 1 inch = 25.4 mm

  • Vertical measurement from the roof surface at the drain to the highest point of the roof surface served by the drain, ignoring a local depression immediately adjacent to the drain.

  TABLE 1105.1(2) DISTANCE OF SCUPPER BOTTOMS ABOVE ROOF

• CPC § 407.2.3 High relevance — show source text

  LAVATORY FAUCETS

  Common and public use areas . . . . . . . . . . . . . .407.2.3 Maximum flow rate . . . . . . . . . . . . . . . . .407.2.1, 407.2.2

  Metering faucet . . . . . . . . . . . . . . . . . . . . . . . . . .407.2.4

  Public . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .407.2.1

  Residential . . . . . . . . . . . . . . . . . . . . . . . . . . . . .407.2.2

  LAWN SPRINKLERS . . . . . . . . .Table 610.3, Table A 103.1,

  A 103.2, M 102.5

  LEAD

  Allowable lead contents . . . . . . . . . . . . . .604.2, 604.2.1

  Bends and traps . . . . . . . . . . . . . . . . . . . . .701.5, 906.6 Closet rings . . . . . . . . . . . . . . . . . . . . . . . . . . . .402.6.1

  Flashing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1102.3.1

  Roof drains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1102.1

  Sheet . . . . . . . . . . . . . . . . . . . . . . .408.8.3, 701.5, 906.6

  Water supply . . . . . . . . . . . . . . . . . . . . . .604.2, 604.2.1

  LEADERS

  Cleanouts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1101.13

  Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .214.0

  Installed outside . . . . . . . . . . . . . . . . . . . . . . . . .1101.4.3

  Leaders, conductors, and connections . . . . . . . .1101.16 Roof drainage . . . . . . . . . . . . . . . . . . . . . . . . . . .1101.12 Size of leaders, conductors, and

  storm drains . . . . . . . . . . . . . . . . . . . . . . . . . . .1103.0

  Sizing roof drains, leaders, and vertical rainwater piping . . . . . . . . . . . . .Table 1103.1 Traps on storm drains and leaders . . . . . . . . . . .1101.15

  LIMITED-DENSITY OWNER-BUILT

  RURAL DWELLING

  Connections to plumbing system . . . . . . . . . . . . . .304.1

• CPC § 1101.13.1 High relevance — show source text

  1101.13.1 Rain Leaders and Conductors. Rain leaders and conductors connected to a building storm sewer shall have a cleanout installed at the base of the

  leader or conductor before it connects to the horizontal

  drain.

  1101.14 Rainwater Sumps. Rainwater sumps serving “public use” occupancy buildings shall be provided with dual pumps arranged to function alternately in the case of overload or mechanical failure. Pumps rated 600 V or less shall comply with UL 778 and shall be installed in accordance with the manufacturer’s installation instructions.

  1101.15 Traps on Storm Drains and Leaders. Leaders and storm drains, where connected to a combined sewer, shall be trapped. Floor and area drains connected to a storm drain shall be trapped.

  Exception: Traps shall not be required where roof drains, rain leaders, and other inlets are at locations permitted under Section 906.0, Vent Termination.

  1101.15.1 Where Not Required. No trap shall be required for leaders or conductors that are connected to a sewer carrying storm water exclusively. 1101.15.2 Trap Size. Traps, where installed for individual conductors, shall be the same size as the horizontal drain to which they are connected.

  1101.15.3 Method of Installation of Combined Sewer. Individual storm-water traps shall be installed on the stormwater drain branch serving each storm-water inlet, or a single trap shall be installed in the main storm drain just before its connection with the combined building sewer. Such traps shall be provided with an accessible cleanout on the outlet side of the trap.

  1101.16 Leaders, Conductors, and Connections. Leaders or conductors shall not be used as soil, waste, or vent pipes nor shall soil, waste, or vent pipes be used as leaders or conductors.

  1101.16.1 Protection of Leaders. Leaders installed along alleyways, driveways, or other locations where exposed to damage shall be protected by metal guards, recessed into the wall, or constructed from the ferrous pipe. 1101.16.2 Combining Storm with Sanitary Drainage. The sanitary and storm drainage system of a building shall be entirely separate, except where a combined sewer is used, in which case the building storm drain shall be connected in the same horizontal plane through a single wye fitting to the combined building sewer not less than 10 feet (3048 mm) downstream from a soil stack.

  1102.0 Roof Drains.

  1102.1 Applications. Roof drains shall be constructed of aluminum, cast-iron, copper alloy of not more than 15 percent zinc, leaded nickel bronze, stainless steel, ABS, PVC, polypropylene, polyethylene, or nylon and shall comply with ASME A112.3.1 or ASME A112.6.4.

  1102.2 Dome Strainers Required. Roof drains shall have domed strainers.

  Exception: Roof drain strainers for use on sun decks, parking decks, and similar areas that are normally serviced and maintained, shall be permitted to be of the flat surface type. Such roof drain strainers shall be level with the deck.

• CPC § 1103.1. High relevance — show source text

  (9) Scupper openings shall be not less than 4 inches (102 mm) high and have a width equal to the circumference of

  208 2025 CALIFORNIA PLUMBING CODE

  ), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.

  STORM DRAINAGE

  the roof drain required for the area served, sized in accordance with Table 1103.1.

  (10)Flashings shall extend above the top of the scuppers.

  (11)At a wall or parapet, 45 degree (0.79 rad) cants shall be installed.

  (12)Separate storm and sanitary drainage systems shall be provided within the building.

  (13)Calculations for the roof drainage system shall be submitted along with the plans to the Authority Having Jurisdiction for approval.

  TABLE 1105.1(1) CONTROLLED-FLOW MAXIMUM ROOF WATER DEPTH

  ROOF RISE* (inches)	MAXIMUM WATER DEPTH AT DRAIN (inches)
  Flat	3
  2	4
  4	5
  6	6

  For SI units: 1 inch = 25.4 mm

  • Vertical measurement from the roof surface at the drain to the highest point of the roof surface served by the drain, ignoring a local depression immediately adjacent to the drain.

  TABLE 1105.1(2) DISTANCE OF SCUPPER BOTTOMS ABOVE ROOF

  ROOF RISE* (inches)	ABOVE ROOF LEVEL AT DRAIN (inches)
  Flat	3
  2	4
  4	5
  6	6

  For SI units: 1 inch = 25.4 mm

  • Vertical measurement from the roof surface at the drain to the highest point of the roof surface served by the drain, ignoring a local depression immediately adjacent to the drain.

  1105.2 Setback Roofs. Drains on setback roofs shall be permitted to be connected to the controlled-flow drainage systems provided:

  (1) The setback is designed for storing water, or

  (2) The square footage of the setback drainage area is converted as outlined in Section 1105.0 to gpm, and the storm-water pipe sizes in the controlled-flow system are based on the sum of the loads.

  (3) The branch from each of the roof drains that are not provided with controlled flow shall be sized in accordance

  with Table 1103.1.

  1106.0 Engineered Storm Drainage System. 1106.1 General. The design and sizing of a storm drainage system shall be permitted to be determined by accepted engineering practices. The system shall be designed by a regis

  TABLE 1105.1(1) CONTROLLED-FLOW MAXIMUM ROOF WATER DEPTH

  For SI units: 1 inch = 25.4 mm

  • Vertical measurement from the roof surface at the drain to the highest point of the roof surface served by the drain, ignoring a local depression immediately adjacent to the drain.

  TABLE 1105.1(2) DISTANCE OF SCUPPER BOTTOMS ABOVE ROOF

  For SI units: 1 inch = 25.4 mm