9.5 POWTS Setbacks, Management, Maintenance Reporting & Abandonment
Key Takeaways
Table 383.43-1 places soil dispersal components at least 10 feet from buildings, 5 feet from property lines, 15 feet from pools and 50 feet from navigable waters, and treatment or holding tanks at least 5 feet from buildings.
NR 812.08 sets well separations of 25 feet to septic and holding tanks and 50 feet to dispersal components under 12,000 gpd (250 feet at 12,000 gpd or more).
Inspection, evaluation, maintenance and servicing reports go to the governmental unit within 30 days, and the governmental unit keeps them at least 6 years.
Pre-July 2000 POWTS with in situ soil components must be visually inspected for surface ponding at least every 3 years, by a plumber, POWTS inspector, septage operator or POWTS maintainer.
Abandoned tanks and pits are disconnected, have their piping sealed, are pumped, and are removed or have their covers removed and are filled with soil, gravel or inert solid material.
Setbacks (SPS 383.43 (8) (i) and Table 383.43-1)
| Physical feature | Soil treatment or dispersal component | Exterior subsurface treatment tank or holding tank | Forcemains, service suction and pump discharge lines |
|---|---|---|---|
| Building | 10 ft | 5 ft (except RV transfer tanks) | None (access permitting) |
| Property line | 5 ft | 2 ft | 2 ft |
| Swimming pool | 15 ft | None | None |
| Ordinary high-water mark of navigable waters | 50 ft | 10 ft | 10 ft |
| Water service and private water main | 10 ft | 10 ft | 5 ft |
| Public water main | Per NR 811 | Per NR 811 | Per NR 811 |
| Well | Per NR 811 and 812 | Per NR 811 and 812 | Per NR 811 and 812 |
Road right-of-way lines may be more restrictive than property lines, and WisDOT has its own highway setbacks.
Well separation (NR 812.08, Table A, selected). NR 812 is DNR's well code. It is not on the exam's reference list, but the plumbing code points to it for every well setback:
| Source | Minimum distance to a well |
|---|---|
| POWTS treatment component (septic tank, aerobic unit, filter) | 25 ft |
| POWTS holding tank | 25 ft |
| POWTS dispersal component under 12,000 gpd | 50 ft (200 ft for school wells) |
| POWTS dispersal component 12,000 gpd or more | 250 ft |
| Grease interceptor (buried) | 25 ft |
| Sanitary building sewer | 8 ft |
| Sanitary collector sewer | 25 ft |
| Pit privy / vault privy | 50 ft / 25 ft |
Worked check. A mound proposed 45 feet from a private well serving a house (design flow 600 gpd) fails NR 812.08's 50-foot dispersal setback. The septic tank, 30 feet from the well, passes its 25-foot setback. The same mound must also be at least 10 feet from the house and 10 feet from the water service.
The management plan (SPS 383.54 (1))
Every POWTS has a management plan, submitted with plan review. It lists the maintenance needed to keep the system working as designed:
- Solids removal requirements
- Influent and effluent quantity and quality
- Metering and monitoring schedules
- Load and rest schedules
- Servicing frequencies
- Installation and inspection checklists
- Mechanical component schedules
- Start-up and shutdown procedures
- Abandonment procedure
Changing how the system is operated requires a written request to the agency that reviewed the plans. Metering, when required, may use event counters and elapsed-time meters, water meters on the supply, or wastewater meters.
Responsibilities (SPS 383.52 and 383.55)
| Party | Duty |
|---|---|
| Owner | Ensures operation and maintenance per the plan, keeps access covers locked or secured, and is responsible for reporting |
| Owner with a plan requiring evaluation or maintenance at intervals of 12 months or less | Keeps a contract with a registered POWTS maintainer |
| Owner with a plan requiring servicing at 12 months or less | Keeps a contract with a certified septage servicing operator (NR 114) |
| Owner or agent | Files each inspection, evaluation, maintenance or servicing report with the governmental unit within 30 calendar days (POWTS ID, location, date and the license, certification or registration number of the person) |
| Governmental unit | Keeps records at least 6 years; runs an inventory of all POWTS and a maintenance program that tracks reports, notifies delinquent owners and reports annually to DSPS |
A POWTS not maintained per its plan, or per SPS 383.54 (4) for older systems, is considered a human health hazard. Chemical or physical restoration products may be used only if department-approved (SPS 383.53).
Older systems (SPS 383.54 (4))
POWTS existing before July 1, 2000 still follow the 1/3 sludge-and-scum and 1-foot-below-inlet servicing triggers. Those with in situ soil components must be visually inspected at least once every 3 years for effluent ponding on the ground surface. The inspection may be done by:
- a licensed master plumber or master plumber-restricted service
- a licensed journeyman plumber or journeyman plumber-restricted service
- a certified POWTS inspector
- a certified septage servicing operator
- a registered POWTS maintainer
A county with a completed inventory may extend the interval to 5 years for occasionally occupied structures.
Abandonment (SPS 383.33)
A subsurface tank or pit that is no longer used as a POWTS component must be abandoned by:
- Disconnecting all piping to the tanks and pits.
- Sealing all disconnected piping.
- Pumping and properly disposing of the contents.
- Either removing the tanks, or removing the covers and filling the tanks and pits with soil, gravel or an inert solid material.
Municipalities may require connection to an available public sewer under s. 281.45, Stats. That is the usual reason a POWTS is abandoned.
Other ch. SPS 386 and 387 items
Ch. SPS 386, under s. 30.71, Stats., regulates sewage from boats equipped with toilets: holding tanks, overboard discharge inactivation and on-shore disposal facilities. Ch. SPS 387 is the Wisconsin Fund financial assistance program for replacing or rehabilitating failing POWTS. Its printed note says the chapter is repealed effective June 30, 2021 under CR 17-065. Both chapters are in the permitted SPS 381 to 387 binder, but neither is central to journeyman installation questions.
What is the minimum horizontal setback from a soil dispersal component to a building under Table 383.43-1?
5 feet
10 feet
15 feet
25 feet
Within how many days must a POWTS servicing report be submitted to the governmental unit under SPS 383.55 (2)?
10 calendar days
60 calendar days
30 calendar days
Within 1 year
Which step is part of abandoning an unused septic tank under SPS 383.33?
Leaving the inlet pipe open so a future system can reuse the tank
Filling the tank with clean water and capping the inlet and outlet
Covering the existing tank with 12 inches of topsoil and seeding it
Pumping it, then removing the tank or removing the cover and filling it with soil, gravel or inert material
Sections you finish are checked off in the contents.