Section SPS 382.365 - Stormwater and clearwater subsurface infiltration plumbing systems(1) SCOPE. The provisions of this section set forth the requirements for the design, installation and maintenance of stormwater and clearwater subsurface infiltration plumbing systems serving building sites. Note: The department of natural resources has registration requirements for class V injection wells. See ch. SPS 382 Appendix for further explanatory material.
(2) SITE AND SOIL EVALUATION. (a)Site evaluation. A site evaluation shall be conducted in accordance with the methods and standards as provided in s. SPS 385.40 (3) (a).(b)Soil evaluation.1. A soil evaluation shall be conducted in accordance with the methods and standards as provided in s. SPS 385.30 (1) (c).2. Individuals qualified to conduct soil evaluation under this subsection shall be an individual that maintains either a registration as provided in s. SPS 305.33 or a license as provided in ch. GHSS 4.(3) INFILTRATION SYSTEM DESIGN. (a)Influent quality. For stormwater and clearwater infiltration plumbing systems, the influent quality shall comply with the requirements in Table 382.70-1 for subsurface infiltration and irrigation.(am)Site evaluation. All infiltration systems must comply with the requirements of Wisconsin department of natural resources standards for site evaluation for stormwater infiltration and bioretention for infiltration.(b)In situ soil requirements.1. Except as provided in subd. 2., the minimum depth of suitable in situ soil for infiltration systems shall be as specified under subd. 1. a. or b. to separate the system from the highest groundwater elevation or bedrock. When groundwater mounding calculations affect the depth to seasonal groundwater, the depth of suitable soil shall be measured to the calculated elevation of mounded groundwater. a. Five feet of suitable soil separation where the soil contains greater or equal to 10 percent and less than or equal to 20 percent fines.b. Three feet of suitable soil separation where the soil contains greater than or equal to 20 percent fines. Note: Wisconsin department of natural resources standards for site evaluation for stormwater infiltration are found in department of natural resources Conservation Technical Standard 1002.
Note: See ch. SPS 382 Appendix for explanatory information.
2. For roof runoff or where treatment has afforded an equivalent level of water quality, the depth of in situ soil shall be no less than one foot of materials finer than coarse sand. Note: See ch. SPS 382 Appendix for representative water quality levels.
(bm)Engineered soil requirements. The installation of a stormwater infiltration system where engineered soil is incorporated in lieu of in situ soil shall comply with all the following:1. The engineered filtering layer shall be located above any limiting factor identified within the soil report.2. The engineered soil may not be less than 24 inches in depth, or 18 inches with supporting documentation and department approval. Note: Wisconsin department of natural resources standards for bioretention for infiltration are found in department of natural resources Conservation Technical Standard 1004.
(d)Groundwater mounding. Groundwater mounding consideration shall be included in the design of any stormwater and clearwater subsurface infiltration plumbing system that has a width that exceeds 15 feet and a depth to the estimated highest groundwater elevation. Note: An acceptable model is provided by the USGS, webpage: http://water.usgs.gov/ogw/techniques.html.
(e)Drain down time.1. Stormwater and clearwater subsurface infiltration plumbing systems shall be designed to drain within 72 hours after a storm event.2. By design, ground surface ponding shall drain within 24 hours after a storm event.(f)Setbacks.1. Stormwater and clearwater subsurface infiltration plumbing systems shall be located as provided in Table 382.365-4, except for irrigation systems. Table 382.365-4
Horizontal Setback Parameters by Physical Feature
Physical Feature | Setback Parameters in feet |
Building | 10 |
Holding tank, stormwater collection tank | 10 |
POWTS dispersal component | 5 |
POWTS holding or treatment component | 10 |
Property line | 5 |
Swimming pool, in ground | 15 |
2. All stormwater and clearwater subsurface infiltration plumbing systems shall be separated from water wells by the applicable separation distances contained in chs. NR 811 and 812 or as otherwise approved by the department of natural resources. Note: See ch. SPS 382 Appendix A-382.30 (11) (d) for material reprinted from ss. NR 811.12 (5) (d) and 812.08. Section NR 811.12 (5) (d) or 812.08 may have additional setback requirements.
(4) INSTALLATION. (a)Orientation. Except for subsurface irrigation systems, all of the following shall apply: 1. The longest dimension of a stormwater or clearwater subsurface infiltration plumbing system consisting in part of in situ soil shall be oriented along the surface contour of the site location, unless otherwise approved by the department.2. The infiltrative surface of a stormwater or clearwater subsurface infiltration plumbing system consisting in part of in situ soil and located below the surface of the original grade shall be level.(b)Other requirements.1. A stormwater or clearwater subsurface infiltration plumbing system consisting in part of in situ soil may not be installed if the soil is frozen at the infiltrative surface.2. Snow cover shall be removed before excavating or installing a stormwater or clearwater system component consisting in part of in situ soil.3. For a stormwater or clearwater subsurface infiltration plumbing system consisting in part of in situ soil, the soil moisture content shall be evaluated immediately prior to installation of the component. If the soil evaluation at the infiltrative surface results in the sample capable of being rolled into a 1/4 -inch wire, the installation may not proceed. Note: To accomplish a field test for soil wetness, a soil sample the size of one's palm may be rolled to form at least a 1/4-inch wire.
4. All vessels and pipes of a stormwater or clearwater subsurface infiltration plumbing system shall be bedded in accordance with a product approval under s. SPS 384.10 or a plan approval under s. SPS 382.20.(5) OPERATION AND MAINTENANCE. (a)General. Operation and maintenance shall be performed in accordance with the operation and maintenance plan submitted with the stormwater and clearwater subsurface infiltration plumbing system design and s. SPS 382.36 (13), where applicable.(b)Prohibited substance.1. Except as provided in subd. 2., no substance shall be discharged into a stormwater or clearwater subsurface infiltration plumbing system that results in exceeding the enforcement standards and preventive action limits specified in ch. NR 140 Tables 1 and 2 at a point of standards application, pursuant to s. 160.21 (2), Stats. Note: For groundwater standard limits on various substances, refer to ch. NR 140 Table 1.
2. Pursuant to s. 160.19 (2) (a), Stats., the department has determined that it is not technically or economically feasible to require that a stormwater or clearwater subsurface infiltration plumbing system treat wastewater to comply with the preventive action limit for chloride specified in ch. NR 140 Table 2, as existed on June 1, 1998. Note: Section 160.19 (2) (a), Stats., reads: "Each regulatory agency shall promulgate rules which define design and management practice criteria for facilities, activities and practices affecting groundwater which are designed, to the extent technically and economically feasible, to minimize the level of substances in groundwater and to maintain compliance by these facilities, activities and practices with preventive action limits, unless compliance with the preventive action limits is not technically and economically feasible."
3. Pursuant to s. 160.21 (2), Stats., the point of standards application relative to the performance of stormwater and clearwater subsurface infiltration plumbing systems is any of the following: a. Any point of present groundwater use for potable water supply.b. Any point beyond the boundary of the property on which the facility, practice or activity is located.(c)Deleterious substance. Substances deleterious to a stormwater or clearwater subsurface infiltration plumbing system shall be intercepted, diluted or treated in accordance with s. SPS 382.34 prior to the substance discharging into a stormwater or clearwater infiltration system.Wis. Admin. Code Department of Safety and Professional Services § SPS 382.365
CR 04-035: cr. Register November 2004 No. 587, eff. 12-1-04; correction in (2) (a), (b) 1., 2., (3) (a), (b) 1., (c) 1., 2., (f) 1., (4) (b) 4., (5) (a), (c), Table 382.365-3 made under s. 13.92(4) (b) 7, Stats., Register December 2011 No. 672.Amended by, CR 23-006: cr. (3) (am), renum. (3) (b) 1. to (3) (b) 1. (intro.) and am., cr. (3) (b) 1. a., b., (bm), r. (3) (c), Table 382.365-1 to Table 382.65-3 Register September 2023 No. 813, eff. 10-1-23; correction in (3) (b) 1. (intro.) made under s. 35.17, Stats., Register September 2023 No. 813, eff. 10/1/2023