Who Owns the Lateral, Town by Town
| Town | The owner's part | The town's part | Backup number |
|---|---|---|---|
| Madison | The whole lateral, from inside the house to the connection at the public main (usually mid-street)(MGO 35.02(4); Engineering homeowner responsibility page) | none (City owns the main only) | 608-266-4430, 24/7(source) |
| Sun Prairie | Sewer service from the street main to the house, including all controls(Sun Prairie Code 13.12.020) | none (City maintains the public sewer system only) | 608-825-0731 weekdays; 608-837-7336 after hours(source) |
| Fitchburg | Not stated. Code defines the building sewer and makes the owner pay to connect it, but doesn't say who maintains it.(source) | — | 608-270-4260; after hours 608-270-4279(source) |
| Middleton | The entire lateral, from the wye at the main to the house(Middleton Code 9.05(8)(a)) | none (City maintains the main; right-of-way repairs by a City-approved plumber) | 608-821-8392, 24/7 on-call(source) |
| Verona | Not stated. Owner pays to install it; the City says it isn't responsible for the customer's service line, without saying where that ends.(source) | — | 608-845-6695, any hour(source) |
| Monona | Not stated. No ownership rule found in the code we could reach.(source) | — | 608-222-2525; after hours 608-222-0463(source) |
| Waunakee | The building sewer from the public main to the building; owner holds title(Waunakee Code Sec. 74-157(c), 74-158(g)) | none (village may repair right-of-way breaks and bill the owner) | 608-849-8111; after hours 608-849-4111(source) |
| McFarland | The building sewer from the public main to the building; owner holds title(McFarland Code Sec. 47-113, 47-151) | none (village may repair right-of-way breaks and bill the owner) | 608-838-7287 weekdays; 608-212-2625 after hours(source) |
| Stoughton | The lateral from the building drain to and including the connection at the main(Stoughton Code Sec. 74-62, 74-89(l)) | none | Call the city |
| Oregon | Not stated. No code text online. Street projects in 2024 and 2026 replaced laterals with the street work.(source) | — | Listed on the village's wastewater page(source) |
| DeForest | Sewer service from the street main to and within the building, including controls(DeForest Code Sec. 8.53(3)(a)) | none (unless damaged by Village negligence) | 608-846-6751(source) |
| Cottage Grove | Not stated. Code is on a site that blocks our checker.(source) | — | 608-839-5813(source) |
| Mount Horeb | Not stated. Code is on a site that blocks our checker.(source) | — | Call the city |
| Maple Bluff | Not stated. Code is on a site that blocks our checker.(source) | — | 608-244-3048(source) |
| Shorewood Hills | Not stated. Sewer chapter requires inspection at connection but doesn't assign maintenance.(source) | — | 608-267-2680; after hours 608-444-6246(source) |
From each town's ordinance or utility page. MMSD, the regional treatment district, says ownership typically runs from the building to the main but some towns end it at the right-of-way, so ask yours.(MMSD) Some towns may repair a break under the street and bill the owner (Waunakee, McFarland, Stoughton).(Waunakee)(McFarland)(Stoughton)
What a Lateral Is
- The pipe that carries everything from your toilets, sinks, laundry and floor drains to the public sewer main, usually under the street.(City of Madison) It slopes downhill from the basement and flows by gravity.(City of Madison)
- Wisconsin's plumbing code calls it the building sewer: the part of the drain system outside the building.(SPS 381)
- Madison: in most of the city the main is in the middle of the street, so your lateral runs under the terrace and half the street.(City of Madison)
- MMSD says property owners must maintain and repair all private laterals, and leaky laterals let groundwater into the sewer, which can cause backups in storms.(MMSD)(MMSD)
Old Pipe Materials
- Madison: modern laterals are usually PVC; older homes may have vitrified clay, cast iron or ductile iron. Your lateral is probably about as old as your house.(City of Madison)(City of Madison)
- MMSD: homes built after 1980 typically have PVC. Clay breaks easily and has weak joints; cast iron corrodes.(MMSD) Clay has a joint every 2 to 3 feet, and roots get in.(City of Madison)
- Orangeburg (bituminous fiber) pipe was used from roughly the early 1950s to the early 1970s and can flatten under soil pressure. A camera can identify it. This comes from the City of Ann Arbor, Michigan; we found no Wisconsin source.(City of Ann Arbor, MI)
- MMSD suggests having a plumber camera-scope the lateral now and then, and before agreeing to a repair, getting the video.(MMSD)(MMSD) Verona suggests root cutting every 3 to 5 years, or yearly for old clay.(City of Verona)
If the Sewer Backs Up
- Call the town first, not a plumber. The crew checks the public main. If the main is flowing, the blockage is in your lateral.(MMSD) Middleton says it won't pay a plumber you called when the main was actually blocked.(Middleton 9.05)
- Madison cleans the main on every backup call and tells you whether the problem is the main or your lateral: 608-266-4430, any time. You can file a claim with City Risk Management; cleanup is the owner's.(City of Madison)
- Insurance. MMSD says standard homeowner and renter policies generally don't cover sewer backups; coverage is often an add-on.(MMSD)
- Backwater valves. Sun Prairie, McFarland and DeForest require one by ordinance.(Sun Prairie)(McFarland)(DeForest) Madison says it isn't required by City or state code but pays part of the cost (below).(City of Madison)
Madison Programs
- Backwater valve rebate: 75% of the lowest of three quotes, up to $1,500, for 1- and 2-unit homes over 5 years old without a working valve, installed by a licensed plumber with a permit.(City of Madison)
- Street patch help: if your lateral repair cuts into an arterial or a street rated above 6 of 10, the City pays for the required 50-foot-wide repaving patch. Single- and two-family homes only.(City of Madison)
- Free video review: Engineering will review a video of your lateral at no charge.(City of Madison)
- The City doesn't do or pay for lateral repairs otherwise.(City of Madison) Sump pumps and downspouts can't drain into the sanitary sewer.(City of Madison)
During Street Projects
- Madison. Under the 2024 Sanitary Sewer Assessment Policy, the City doesn't assess rebuilding the main. When it replaces your lateral with a similar-size one during a City street or sewer project, you're assessed 25%; a lateral replaced outside a City project is 100% yours.(City of Madison)
- On those projects the City replaces the lateral from the main to the property line, usually about a foot behind the sidewalk, not the part on your lot.(City of Madison) On one 2026 project, good cast-iron laterals under trees were replaced only to the back of the curb, and owners weren't assessed for the skipped footage.(City of Madison)
- Assessments show up on the tax bill. Madison special assessments explains the letters, hearings and payment plans.
- Oregon replaced clay mains and laterals on South Main Street in 2024, paying for street and underground work from the general fund.(Village of Oregon)
Who Can Do the Work
- Lateral work is plumbing and needs a licensed plumber, except an owner working on a one-family home they own and live in, unless the town requires a license. Clearing a stoppage is exempt.(Wis. Stat. 145.06) Here's how to check a plumber's license.
- In Madison, work in the street or terrace must be done by a contractor the City has licensed and prequalified; work on your lot can be done by you or your plumber.(City of Madison)(MGO 35.02)
- Call Diggers Hotline before any digging. Diggers Hotline shows when you can start, and which private lines it doesn't mark.
Badger Homeowner doesn't recommend contractors and takes no money from them.
Questions
Who owns the sewer lateral in Madison?
The homeowner owns the whole private sewer service, from inside the house to where it connects to the City main, which is usually in the middle of the street. The City doesn't do or pay for lateral repairs, except during City street and sewer projects.
Does Madison replace sewer laterals during street reconstruction?
Usually, from the new main to the property line. Under the City's 2024 policy you're assessed 25% of the cost of a similar-size replacement lateral during a City street or sewer project. Outside a City project you pay 100%.
What should I do about a sewer backup?
Call your city's sewer number first. The crew checks the public main; if the main is flowing, the problem is your lateral and clearing it is your job. In Madison call 608-266-4430, any time.
What is Orangeburg pipe?
A bituminous fiber pipe used for sewer laterals from roughly the 1950s to the early 1970s. It can flatten under soil pressure. Our source is the City of Ann Arbor, Michigan; we found no Wisconsin agency page on it.