Section 382.36. Stormwater and clearwater plumbing systems.

 

(1)   Scope. The provisions of this section set forth the requirements for the design, installation and maintenance of piping, conveyance, venting, detention and treatment of stormwater and clearwater in plumbing systems.

(2)   Materials. All stormwater and clearwater plumbing systems shall be constructed of approved materials in accordance with s. SPS 384.30 (3) .

(3)   Design of stormwater plumbing systems.

(a) Plumbing systems upstream of detention shall be designed, at a minimum, based on the 10-year, 24-hour storm event.

(b) Plumbing detention systems and plumbing systems located downstream of detention shall be designed based on anticipated flows and volumes.

(c) Stormwater and clearwater infiltration systems shall comply with s. SPS 382.365 .

(4)   Discharge, dispersal, clearwater reuse or stormwater use.

(a) Discharge points. The discharge points for stormwater and clearwater shall be as specified in Table 382.38-1.

(b) Segregation of wastewater.

1. Except as provided in subd. 2. , stormwater or clearwater piping may not connect to a sanitary drain system.

2. Where a combined sanitary-storm sewer system is available, stormwater, clearwater and sanitary wastewater may be combined in the building sewer.

3. Stormwater gravity drains shall not be combined with clearwater drains prior to discharging to the storm building drain except where approved by the department.

(5)   Input calculations.

(a) Peak flow. The peak flow of stormwater influent to a plumbing system shall be calculated using any of the following methods:

1. `Area method.' For sizing of conveyance piping, when calculating stormwater peak flow based on the tributary area, the area in square feet shall be divided by the following applicable divisors:

a. For roofs the divisor is 26 square feet/gpm.

b. For paved or graveled ground surfaces the divisor is 32.5 square feet/gpm.

c. For lawns, parks and similar land surfaces the divisor is 104 square feet/gpm.

2. `Rational method.' For calculating peak flow, the intensity shall be determined using the time of concentration for the tributary area.

3. `Engineering analysis method.' An engineering analysis, acceptable to the department, shall be based on the peak flow calculated in accordance with sub. (3) (a) .

(b) Volume. The volume of stormwater influent to a plumbing system shall be based on an engineering design acceptable to the department and a minimum of a two-year, 24-hour storm event and designed so that no property damage occurs at 100-year, 24-hour storm event with a Type II distribution.

(c) Additional inputs to stormwater systems. Additional inputs to stormwater systems shall be estimated based on anticipated flows and volumes.

(6)   Conveyance and detention systems.

(a) Design. The design of stormwater and clearwater conveyance systems shall conform to all of the following:

1. Horizontal stormwater conveyance piping shall be sized using either of the following:

a. An engineering analysis, based on full flow capacity, acceptable to the department.

b. Tables 382.36-1 to 382.36-5 based on pipe type, diameter and pitch.

2.

a. A vertical conductor for stormwater may not be smaller than the largest horizontal branch discharging into the conductor.

b. Vertical conductors shall be sized in accordance with Tables 382.36-1 and 382.36-3 or by an engineering analysis acceptable to the department.

3. Clearwater conveyance systems shall be sized in accordance with s. SPS 382.30 (3) and (4) .

4. Underground, gravity-flow storm building sewers shall have a minimum 3-inch inside diameter.

(b) Velocity in stormwater conveyance system piping. The pitch of stormwater conveyance system piping shall be designed to create a minimum velocity of one foot per second when flowing full.

(c) Fittings and connections.

1. Except as provided in subd. 2. , fittings and connections for stormwater and clearwater conveyance systems shall comply with s. SPS 382.30 (8) and (9) .

2. The minimum radius for the first 90 ° fitting located downstream of a roof drain shall comply with the horizontal to vertical requirements in Table 382.30-4.

(d) Stack offsets. Stack offsets for piping of a clearwater conveyance system piping shall comply with s. SPS 382.30 (6) .

(e) Pitch of clearwater gravity conveyance system piping.

1. The minimum pitch of gravity conveyance system piping having a 2-inch inside diameter or less shall be 1/8 inch per foot.

2. The minimum pitch of clearwater gravity conveyance system piping having at least a 3-inch inside diameter or more shall be 1/16 inch per foot.

(f) Branch connections near base of stack. Branch drains from interior clearwater inlets may not connect downstream from the base fitting or fittings of a drain stack within a distance equal to 20 pipe diameters of the building drain.

(g) Detention systems.

1. The storage volume of a dry detention system shall be designed and installed with a drain time of 72 hours after a storm event.

2. Paved surfaces or parking lots serving as detention areas shall be limited to a design depth of 6 inches, unless otherwise limited by local ordinance.

3. By design, ground surface ponding shall drain within 24 hours after a storm event. - See PDF for table

(7)   Other design requirements.

(a) Subsoil drains.

1. A subsoil drain discharging to a plumbing system shall discharge into an area drain, manhole or storm sewer, trapped receptor or a sump with a pump.

2. Where a foundation drain is subject to backwater, the drain shall be protected by a backwater valve or a sump with a pump.

(b) Backwater valve. All backwater valves shall be accessible for maintenance.

(c) Sewer location.

1. No storm building sewer or private interceptor main storm sewer may pass through or under a building to serve another building, unless one of the following conditions is met:

a. The storm building sewer or private interceptor main storm sewer serves farm buildings or farm houses, or both, that are located on one property.

b. Where a storm building sewer or private interceptor main storm sewer serves buildings that are located on one property, a document that indicates the piping and distribution arrangement for the property and buildings is recorded with the register of deeds no later than 90 days after installation.

2. The location of storm building drains and building sewers shall comply with ss. SPS 382.30 (11) (d) and 382.40 (8) (b) 7.

(d) Installation requirements.

1. The connection of a stormwater leader discharging to a storm building sewer shall be made above the finished grade.

2. The elevation of a storm building drain shall comply with s. SPS 382.30 (11) (b) 1.

3. Interior inlets and drains subject to backflow or backwater shall be protected with a check valve or backwater valve.

4. Storm building drains and building sewers shall be installed to comply with s. SPS 382.30 (11) (e) .

5. Storm building sewer connections to public sewers shall be in accordance with s. SPS 382.30 (11) (f) .

6. Cleanouts for conveyance system piping shall be installed in accordance with s. SPS 382.35 .

7. Storm building sewers that receive clearwater and that may be subject to freezing shall be installed in accordance with s. SPS 382.30 (11) (c) 2.

8. Storm building drains, clearwater building drains, and building storm sewers and appurtenances shall be separated from water wells by the applicable separation distances contained in chs. NR 811 and 812 , or as otherwise permitted by the department of natural resources.

9. All underground stormwater storage tanks for water reuse shall be separated from sanitary sewers by a minimum of 8 feet.

10.

a. A means to locate buried non-metallic storm building sewers and private interceptor main sewers that discharge to municipal mains shall be provided in accordance with the options under s. SPS 382.30 (11) (h) , except as provided in subd. 10. b.

b. Tracer wire insulation color for non-metallic storm pipe shall be brown.

(8)   Sumps and pumps.

(a) Sumps.

1. `General.' All storm building subdrains shall discharge into a sump, the contents of which shall be automatically lifted and discharged, dispersed or used in accordance with sub. (4) .

2. `Construction and installation'.

a. Except as provided in subd. 2. c. and d. , an interior sump shall have a rim extending at least one inch above the floor immediately adjacent to the sump.

b. A sump shall have a removable cover of sufficient strength for anticipated loads.

c. Where a sump is installed in an exterior meter pit or elevator pit, the rim may be level with the floor.

d. When a sump is provided with an airtight, solid cover.

3. `Location'. All sumps installed for the purpose of receiving clearwater, groundwater or stormwater shall be separated from water wells by the applicable separation distances contained in chs. NR 811 and 812 , or as otherwise permitted by the department of natural resources.

4. `Size'.

a. Except as permitted under subd. 4. b. or c. the size of each sump shall be no smaller than 16 inches in diameter at the top, 14 inches in diameter at the bottom, and 22 inches in depth.

b. The minimum sump diameter may be smaller than 16 inches when specified by the manufacturer for a combination sump and pump.

c. A sump located in an elevator pit may have a width or diameter of not less than 12 inches and a depth of not less than 12 inches.

(b) Pumps.

1. `Size.' The pump shall be of a capacity appropriate for the anticipated use.

2. `Discharge piping.'

a. Where a pump discharges into a storm drain system, a check valve shall be installed.

b. The minimum diameter discharge piping shall be based on the design flow rate of the pump and a minimum velocity of one foot/second.

(9)   Inlet requirements.

(a) Interior clearwater drain inlets. Interior clearwater drain inlets shall terminate at least one inch above the finished floor.

(b) Exterior stormwater inlets.

1. `Construction.'

a. All exterior stormwater inlets shall be constructed of material in accordance with s. SPS 384.30 .

b. All exterior stormwater inlets subject to vehicular traffic shall be set on a suitable base capable of sustaining the anticipated load.

2. `Design'. All exterior stormwater inlets shall be designed for the anticipated flow.

3. `Inlet grates'.

a. General. All inlets shall be provided with a well-fitted, removable grate of a thickness and strength to sustain the anticipated loads.

b. Floor or ground surface inlets. Openings in the floor or ground surface shall be of a size that prohibits the entrapment of wheeled vehicles, wheelchairs or pedestrians within the grate openings.

c. Grates on horizontal pipes. Grates shall be provided on horizontal inlets greater than 6 inches in diameter. The grates shall be placed so that the rods or bars are not more than 3 inches downstream of the inlet. Rods or bars shall be spaced so that the openings do not permit the passage of a 6-inch sphere.

(c) Subsurface areas of 50 square feet or less. Other than stairwells, all subsurface areas not exceeding 50 square feet and exposed to the weather, shall comply with one of the following:

1. Drain to foundation drains through a minimum 2-inch diameter pipe or a through a continuous layer of washed stone aggregate.

2. Drain to the storm building drain, storm subdrain or storm sewer through a minimum 3-inch diameter pipe.

(d) Subsurface areas of more than 50 square feet and stairwells. An area drain shall be provided in subsurface areas greater than 50 square feet and in all stairwells exposed to the weather. The area drain shall comply with all of the following:

1. Drain to the storm building drain, storm subdrain or storm sewer.

2. The fixture drain shall have a minimum 3-inch inside diameter and may not discharge into a subsoil or foundation drain.

(10)   Roof drains.

(a) General roofs. Roof drains shall be equipped with strainers extending not less than 4 inches above the surface of the roof immediately adjacent to the roof drain. Strainers shall have an available inlet area above the roof of not less than 1.5 times the area of the conductor to which the drain connects.

(b) Flat decks. Roof drain strainers used on sun decks, open parking decks and similar areas shall be of the flat surface type, shall be level with the deck and shall have an available inlet area of not less than 2 times the area of the conductor to which the drain connects.

(11)   Secondary roof drains.

(a) Sizing. When secondary roof drain systems are installed the secondary system shall be sized and installed in accordance with the requirements in this section.

(b) Prohibited connection. Secondary roof drain systems may not be connected to primary roof drain systems.

(c) Discharge. All secondary roof drain systems shall discharge in accordance with Table 382.38–1.

(12)   Traps and vents.

(a) Traps.

1. Traps are required for interior drain inlets receiving clearwater.

2. Except for exterior loading dock drains, traps are required for exterior drain inlets located within 10 feet of an air inlet, door or openable window.

3. More than one drain inlet may discharge to the same trap.

4. A foundation drain that discharges by gravity to a storm sewer shall be trapped. The trap shall be provided with cleanouts.

(b) Vents.

1. A trap receiving clearwater shall be vented in accordance with s. SPS 382.31 . Vent piping for a clearwater drain system may not be connected to a vent system serving a sanitary drain system or chemical waste system.

2.

a. Vents serving a solid covered sump shall terminate a minimum of one inch above finished floor.

b. Sump vents shall be sized as per Table 382.31-4.

(13)   Operation and maintenance.

(a) Plan. An operation and maintenance plan shall be implemented for all stormwater plumbing systems for drainage areas of one or more acres that are installed on or after December 1, 2004.

(b) Plan information. An operation and maintenance plan as required in par. (a) shall include at least all of the following information, applicable to the system:

1. Accumulated solids or byproduct removal requirements.

2. Identification of safety hazards.

3. Cleaning and inspection schedule.

4. Inspection and maintenance checklist, including at least the following items:

a. Filters.

b. Disinfection units.

c. Sedimentation chambers.

d. Detention devices.

e. Infiltration systems.

5. Start up and shutdown procedures.

6. Vector control requirements.

7. A contingency plan in the event of system failure.

(c) Plan location. The operation and maintenance plan shall remain onsite and be available for inspection when requested by the department.

(d) Record of maintenance. When requested the owner shall make available for inspection all maintenance records to the department or agent for the life of the system.

Cr. Register, February, 1985, No. 350 , eff. 3-1-85; r. and recr. (3) (a) and (b) 1., (c) 1. and (11) (a) 4., cr. (3) (c) 3., Register, May, 1988, No. 389 , eff. 6-1-88; renum. (13) (a) and (b) to be (b) and (c) and am. (b) 1., cr. (3) (b) 3. and (13) (a), r. (3) (c) 3. and (13) (intro.), Register, August, 1991, No. 428 , eff. 9-1-91; reprinted to correct error in (5) (e) 2., Register, October, 1991, No. 430 ; am. (3) (b) 1., (c) 1. a., (13) (b) 1. and (c), cr. (11) (a) 5., Register, February, 1994, No. 458 , eff. 3-1-94; r. and recr. (11) (a) 2. and 5., Register, April, 1998, No. 508 , eff. 5-1-98; renum. and am. (3) (b) 3. a. to be (3) (b) 3. and (3) (b) 3. b. to be (3) (b) 4., Register, April, 2000, No. 532 , eff. 7-1-00; am. (3) (b) 3., (4) (a), (5) (a) and (6) (a), cr. (3) (b) 5. and Table 82.36-4a, Register, December, 2000, No. 540 , eff. 1-1-01; CR 02-002 : r. and recr. (3), (11) (a) 3., (13) (a) 2., (15) (a) and (b), am. (5) (e) (intro.), (10), (12), (14) and Table 82.36-4 Register April 2003 No. 568 , eff. 5-1-03; CR 04-035 : r. and recr. Register November 2004 No. 587 , eff. 12-1-04; CR 07-069 : cr. (7) (d) 10. Register February 2008 No. 626 , eff. 3-1-08; CR 08-055 : am. (4) (b) 3. and (8) (a) 4., r. and recr. (11) Register February 2009 No. 638 , eff. 3-1-09; correction in (2), (3) (c), (4) (a), (6) (a) 1. b., 2. b., 3., (c) 1., 2., (d), (7) (c) 2., (d) 2., 4., 5., 6., 7., 10. a., (9) (b), (11), (c), (12) (b) 1., 2. b. made under s. 13.92 (4) (b) 7. , Stats., Register December 2011 No. 672 .

Note

Refer to ch. NR 151 for stormwater management requirements. Microsoft Windows NT 6.1.7601 Service Pack 1 For a listing of best management practices (BMPs) refer to ch. SPS 382 Appendix A-382.36 (3)-1. Microsoft Windows NT 6.1.7601 Service Pack 1 Where local discharge requirements are more stringent, stormwater plumbing systems may provide detention and treatment to comply with the local stormwater management plan. Microsoft Windows NT 6.1.7601 Service Pack 1 See also Table SPS 382.38-1 which limits clearwater discharges to sanitary sewer at 50 gpd. Microsoft Windows NT 6.1.7601 Service Pack 1 For the use of stormwater or reuse of clearwater, refer to the appropriate requirements in ss. SPS 382.30 , 382.34 , 382.40 , 382.41 , 382.70 and this section. Microsoft Windows NT 6.1.7601 Service Pack 1 For further explanatory material regarding the rational method, other methods and runoff co-efficients, see ch. SPS 382 Appendix A-382.36 (4). Microsoft Windows NT 6.1.7601 Service Pack 1 For example, 10,000 square feet of roof area/26 square feet/gpm = 385 gpm or 0.85 cubic feet/second. Microsoft Windows NT 6.1.7601 Service Pack 1 For the equation procedure for runoff coefficients for use with the rational method, refer to ch. SPS 382 Appendix A-382.36 (5)-1. Microsoft Windows NT 6.1.7601 Service Pack 1 A model that calculates peak flow such as SWMM, TR-20, TR-55, P8 or an equivalent methodology may be used. Microsoft Windows NT 6.1.7601 Service Pack 1 For runoff coefficients and use of other methods or models, refer to ch. SPS 382 Appendix A-382.36 (5)-2 and A-382.36 (5)-3. Microsoft Windows NT 6.1.7601 Service Pack 1 The intensity of rainfall varies considerably during a storm as well as geographic regions. To represent various regions of the United States, the U.S. Department of Agriculture (USDA), Natural Resources Conservation Service (NRCS) developed four synthetic 24-hour rainfall distribution types from available National Weather Service (NWS) duration-frequency data (Hershfield 1961; Frederick et al., 1977) or local storm data. Type IA is the least intense and type II is the most intense short duration rainfall. Types I and IA represent the Pacific maritime climate with wet winters and dry summers. Type III represents Gulf of Mexico and Atlantic coastal areas where tropical storms bring large 24-hour rainfall amounts. Type II represents the rest of the country, including Wisconsin. For more information, see the USDA-NRCS webpage: http://www.nrcs.usda.gov/ . Microsoft Windows NT 6.1.7601 Service Pack 1 For the use of Baird's equation, refer to ch. SPS 382 Appendix A-382.36 (6)-1. Microsoft Windows NT 6.1.7601 Service Pack 1 To convert to cubic feet per second (cfs) divide gpm by 448.8. - See PDF for table Microsoft Windows NT 6.1.7601 Service Pack 1 To convert to cubic feet per second (cfs) divide gpm by 448.8. - See PDF for table Microsoft Windows NT 6.1.7601 Service Pack 1 To convert to cubic feet per second (cfs) divide gpm by 448.8. - See PDF for table Microsoft Windows NT 6.1.7601 Service Pack 1 To convert to cubic feet per second (cfs) divide gpm by 448.8. - See PDF for table Microsoft Windows NT 6.1.7601 Service Pack 1 For more information regarding joints and connections, refer to s. SPS 384.40 . Microsoft Windows NT 6.1.7601 Service Pack 1 See ch. SPS 382 Appendix A-382.30 (11) (d) for material reprinted from s. NR 812.08 . Microsoft Windows NT 6.1.7601 Service Pack 1 For additional information on approved materials, refer to s. SPS 384.30 (3) (f) . Microsoft Windows NT 6.1.7601 Service Pack 1 For manhole requirements, refer to s. SPS 382.35 (3) . Microsoft Windows NT 6.1.7601 Service Pack 1 Sections SPS 362.1101 to 362.1110 specify that for floor or ground surface inlets when placed within an identifiable accessible route, openings in the floor or ground surface shall be of a size that does not permit the passage of a ½ -inch sphere. Also, it states that grates having elongated openings be placed so that the longest dimension is perpendicular to the dominant direction of travel. Microsoft Windows NT 6.1.7601 Service Pack 1 See ch. SPS 382 Appendix for further explanatory material. Microsoft Windows NT 6.1.7601 Service Pack 1