Cohasset · Sewer Lines
Recurring backups, roots, or a broken pipe under a Cohasset yard? First confirm whether your house drains to a town sewer district or a septic system, then call to reach an independent plumber.
Cohasset, Massachusetts
Before anyone digs in a Cohasset yard, settle a basic question: does the pipe leaving your house run to a town sewer main or to a septic tank? The town has both. The Sewer Commission, set up by an act of the State Legislature in 1962, serves a Central District and a much smaller North Cohasset District, while other homes treat their wastewater on site under Title 5. The repair, the permit path, and the people involved differ for each.
On a sewered lot, the building sewer is the pipe between your foundation and the town's main, and work on it touches the town system. On a septic lot, the same symptoms might come from the line to the tank, the tank itself, or the leaching field, and the Board of Health has its own rules on top of the state code.
Call or send a request to be connected with an independent plumber who handles sewer line work in Cohasset. We're a referral site, not a contractor, so the plumber you reach inspects, quotes, and does the repair.
If a main line clears and clogs again within weeks, roots, a sag, or a broken section usually lie underneath.
An odor outdoors along the path of the pipe, or near the tank on a septic lot, suggests waste is escaping where it shouldn't.
Grass that grows greener in a line, or soil that settles over the pipe route, can mark a leak or collapse below.
When sinks, tubs, and toilets all drain slowly together, the problem is in the shared line leaving the house.
Local knowledge
Local facts that decide who's involved when a Cohasset building sewer fails.
Sewer Districts
The town's sewer account list, as archived in February 2026, counted 1,599 accounts in the Central District and 52 in the North Cohasset District. If you're on that list, the Sewer Commission at Town Hall is the first call about a problem at or near the town main.
Source: Cohasset Sewer Commission (archived page, February 2026)
Drainlayer Lists
The Sewer and Water departments each posted a 2025 list of drainlayers with a town license, per the Sewer Department page archived in February 2026. If your job ties into a town main, ask whether the company is on that list before you sign.
Source: Cohasset Sewer Department (archived page, February 2026)
Septic Rules
The Board of Health posts the state Title 5 septic code and Cohasset's supplemental rules and regulations, according to its page archived in March 2026. Replacing a pipe to a septic tank or field may need Board of Health review as well as a plumber.
Source: Cohasset Public Health Department (archived page, March 2026)
Sewer Expansion History
The town's 2019 master plan draft says a treatment plant expansion allowed connections along Little Harbor and Atlantic Avenue, and that a sewer line along Route 3A, where businesses had struggled with septic, was under study at the time. Homes in those areas may have newer connections than the village center.
Source: Cohasset Master Plan land use chapter (final draft, May 2019)
Right now
Protect your household, then find out which system you're dealing with.
Sewage carries germs that make people sick. Keep children and pets away, wear gloves and boots if you must go near it, and stay clear of wet outlets and cords.
Stop laundry, dishwashing, and showers so less wastewater pushes toward a blocked or broken line.
Look for a town sewer bill. If you have one, call the Sewer Commission about anything near the street; if not, you're likely on septic and should contact a septic service and the Board of Health as needed.
Locate the capped cleanout on the main line in the basement or just outside the foundation so the plumber can get a camera in without delay.
What to expect
Expect a camera inspection first. The plumber runs a camera through the cleanout to find roots, cracks, sags, or a collapse, and records how far from the house it is. That footage tells you whether the trouble is on your side, near the town main, or at the septic tank.
Repairs range from cutting roots and patching one joint to replacing the whole line, either by trenching or with trenchless methods where the pipe and soil allow. Ask whether work at the town main calls for a drainlayer on the town's list; plumbing changes inside the house go through Building & Inspections, which, as of its archived February 2026 page, takes permits online.
On a septic property, the repair may lead to a septic inspection or Board of Health review, especially if the tank or field turns out to be part of the problem.
Hire smart
Plumbing and gas fitting in Massachusetts require a license from the Board of State Examiners of Plumbers and Gas Fitters, and most plumbing work needs a permit from the town's plumbing inspector.
Confirm the plumber's Massachusetts license on the state's occupational license search before any digging starts.
For a connection to a town main, ask if the company is on Cohasset's current drainlayer list or will bring in one that is.
Request a copy of the inspection footage so you can see the damage yourself or share it for a second opinion.
Ask for both methods to be priced and explained where they're possible, including yard, driveway, or landscaping restoration.
Costs
The length and depth of the line, the pipe material, what sits on top of it, and whether the break is near the town main all shape the price. Ledge, mature trees, stone walls, or a long driveway over the pipe route can add digging time, while a short root problem near the house may need only a spot repair.
Ask for a written estimate that lists the inspection, the repair method, permits, any drainlayer work, and restoration. For a full replacement, a second written estimate and the camera footage to back both up are worth having before you decide.
More help in Cohasset
Every page below is written for Cohasset homes. Or start from the Cohasset plumbing guide.
Learning Center
A short list of the right questions tells you more about a plumber than any ad. Use these on the phone, during the site visit, and before you sign off on an estimate.
Read the guide
Massachusetts has some of the clearest plumbing rules in the country. Here is how to use them to pick a plumber with confidence, whether the job is a dripping shutoff or a full repipe.
Read the guideQuestions
Still not sure? Send a short request and a local pro can answer the specifics.
If you get a sewer bill from the town, you're in either the Central or North Cohasset district. If not, your home probably has a septic system. The Sewer Commission office at Town Hall can confirm your address.
The town's Water and Sewer departments each posted a 2025 list of drainlayers holding a Cohasset license. Ask your plumber whether they're on the list or will work with someone who is, and check with the Sewer Commission about its requirements.
It may. The Board of Health applies the state Title 5 code and Cohasset's own supplemental rules to septic systems. Ask your plumber or a septic professional whether your repair needs a Board of Health permit before work begins.
Often, if the existing pipe is intact enough to line or burst and there's access at both ends. A camera inspection will show whether it's an option. Ask the plumber to explain what conditions on your lot might rule it out.
Get connected
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