1.5 Code Structure, Key Definitions, Basic Principles & Referenced Standards
Key Takeaways
The Wisconsin Plumbing Code is chs. SPS 381 to 387, a uniform statewide code: municipalities may not adopt plumbing design or installation ordinances more stringent than SPS 382 unless a rule allows it.
SPS 382 is not retroactive unless a rule says so, and DSPS interpretations override those of lower jurisdictions.
Every dwelling connected to a POWTS or public sewer needs at least one water closet, one wash basin, one kitchen sink and one bathtub or shower (SPS 382.10 (2) (b)).
A water service runs from the main or private supply up to and including the building control valve; a private water main or private interceptor main sewer serves 2 or more buildings.
Alternate standards that are equivalent or more stringent may replace referenced standards with written DSPS approval, decided within 40 business days (SPS 381.20 (2)).
How the plumbing chapters fit together
| Chapter | Content |
|---|---|
| SPS 381 | Definitions (381.01) and standards incorporated by reference (381.20 and Tables 381.20-1 to -13) |
| SPS 382 | Design, construction, installation, supervision, maintenance and inspection of plumbing: plan review, testing, drain and vent, traps, interceptors, cleanouts, storm, water supply, cross connection, health care, manufactured homes, hangers, treatment standards |
| SPS 383 | Private onsite wastewater treatment systems |
| SPS 384 | Plumbing products: approvals, fixtures, materials, joints |
| SPS 385 | Soil and site evaluations |
| SPS 386 | Plumbing for boats (sewage holding and disposal) |
| SPS 387 | Wisconsin Fund POWTS financial assistance |
| SPS 302 | Fees: plan review, permits, variances, product approvals, cross connection assembly fees |
| SPS 325 | Uniform Dwelling Code plumbing chapter: one- and 2-family dwelling plumbing complies with chs. SPS 381 to 387; sanitation devices such as composting toilets and privies comply with ch. SPS 391 (revised by CR 26-019) |
| SPS 305 | Licenses, certifications and registrations |
Wisconsin writes its own plumbing code. It doesn't adopt the IPC or UPC, although it incorporates many ASME, ASSE, ASTM, CSA, NSF and NFPA product and installation standards by reference.
Scope, uniformity and authority (SPS 382.01 to 382.03)
- SPS 382 covers sanitary and storm drainage, water supplies, wastewater treatment and discharge for buildings. POWTS are under SPS 383.
- Its purpose (SPS 382.015, s. 145.02) is that all plumbing be safe, sanitary and protective of public health and the waters of the state.
- The chapter is not retroactive unless a rule says so.
- It is uniform. A municipality may not enact an ordinance for plumbing design, construction, installation, supervision, maintenance or inspection more stringent than SPS 382 except where a rule allows. Municipalities may still require local permits and inspections (s. 145.04).
- DSPS interpretations and decisions supersede those of lower jurisdictions. Department decisions may be appealed under s. 101.02 (6) (e).
Basic principles (SPS 382.10)
The code's intent statements are used to judge equivalency when a situation isn't specifically covered. Plumbing must:
- protect health, safety and the waters of the state
- supply enough water at adequate pressure without undue noise, while using the minimum water consistent with performance
- prevent explosion or overheating of water heating vessels
- drain efficiently with adequate cleanouts
- circulate air so trap seals aren't siphoned or forced
- be durable and well made
- prevent backflow contamination of food, water and sterile goods
- space fixtures for use and cleaning
Basic requirements:
- Every building for human occupancy has an adequate, safe, potable water supply.
- Each dwelling (except camping units) connected to a POWTS or public sewer has at least one water closet, one wash basin, one kitchen sink and one bathtub or shower. A ch. SPS 391 device may substitute for the water closet. Fixture counts for other buildings come from chs. SPS 361 to 366.
- Hot or tempered water goes to fixtures that need it.
- Buildings without public sewer must treat, recycle, disperse or hold their wastewater.
- Fixtures are durable, smooth, nonabsorbent, corrosion-resistant and free of concealed fouling surfaces.
Definitions to know cold (SPS 381.01 and s. 145.01)
| Term | Meaning |
|---|---|
| Plumbing (s. 145.01 (10)) | Piping, fixtures, appliances and devices of water supply, distribution, drainage, reclaimed water and stormwater use systems, including water heaters, treatment devices and their installation; sewer and water service piping to the main; POWTS. It excludes gutters and downspouts down to their discharge into a plumbing system or subsoil or foundation drain, process water reuse not connected to fixtures, and culverts |
| Branch interval | A vertical distance of 8 feet or more between horizontal branch connections to a stack |
| Building drain | Horizontal piping within or under the fully enclosed building, below the lowest fixture, draining by gravity to the sewer |
| Building sewer | The drain system outside the fully enclosed building, carrying discharge to a public sewer, private interceptor main sewer, POWTS or other point |
| Developed length | Length measured along the centerline of pipe and fittings |
| Indirect waste piping | Drain piping discharging through an air break or air gap into a receptor |
| Local waste piping | Piping that receives indirect waste and discharges through an air break or air gap into a receptor |
| Private interceptor main sewer / private water main | Serves 2 or more buildings and is not part of the municipal system |
| Water service | From the water main or private supply up to and including the building control valve |
| Vent stack / stack vent | A vent stack provides air for a drain stack of 5 or more branch intervals; a stack vent extends from the highest horizontal drain connected to a stack |
| Wet vent | The portion of a vent pipe that receives discharge from other fixtures |
| Clear water / storm water | Clear water is wastewater other than storm water with no harmful impurities (cooling water, condensate); storm water is wastewater from precipitation |
| Lead-free | No more than 0.2% lead in solder and flux and a 0.25% weighted average on wetted surfaces |
| Public building / place of employment | As defined in s. 101.01 (12) and (11), Stats.; a public building is used by the public or by 3 or more tenants |
Referenced and alternate standards (SPS 381.20)
Standards listed in Tables 381.20-1 to 381.20-13 apply to the extent the code references them, including standards they in turn reference, except as the code modifies them. Examples are NFPA 13D-2019, NFPA 24-2019, ASSE series, ASME A112 series, ASTM pipe standards and ANSI/ISEA Z358.1.
Alternate standards that are equivalent or more stringent may be used instead with DSPS approval:
- A written request and fee are required, decided within 40 business days.
- The approval is based on an analysis by an independent third party or the standard's publisher.
- DSPS may attach conditions or an expiration date.
The IAPMO Peak Water Demand Calculator is a code-noted example for water pipe sizing (SPS 382.40 (7)).
Exam tip
Many items test which chapter governs a question. Septic tank setbacks are in SPS 383, not 382. Pipe material lists are in SPS 384, not 382. A journeyman's supervision is in SPS 305. Soil tester duties are in SPS 385. Knowing the map lets you open the binder to the right tab in seconds.
Under SPS 382.03 (2), what may a Wisconsin municipality NOT do?
Require local plumbing permits and inspections for new work
Adopt installation rules stricter than SPS 382 without a rule allowing it
Employ a licensed plumbing inspector to review plans and inspect work
Require buildings next to a sewer main to connect to the public sewer system
Where does a water service end under SPS 381.01 (282)?
At the property line or the curb stop
At the outlet of the water meter
Up to and including the building control valve
At the first branch serving a fixture inside
What minimum fixtures does SPS 382.10 (2) (b) require for a dwelling connected to a public sewer?
One water closet, one wash basin, one kitchen sink and one bathtub or shower
One water closet and one lavatory, with a kitchen sink only where cooking occurs
Two water closets and two lavatories for any dwelling over 2,000 square feet
A kitchen sink, a laundry tray and one water closet, with bathing fixtures optional
Sections you finish are checked off in the contents.