Sewer line replacement cost in Somerville and Greater Boston: camera, lining or dig
Sewer line replacement cost for old clay and cast-iron lines in Somerville and Greater Boston: camera inspection, lining vs digging, drain layer permits.
Mateus MagnoLicensed Construction Supervisor · November 2, 2026 · 4 min read
Sewer line replacement cost depends on the length of the line, its depth, whether it runs under the street, and whether it can be lined instead of dug up. HomeGuide puts the national average at $50 to $250 per linear foot, or $2,000 to $10,000 for a 40-foot line, and Greater Boston usually runs higher. In Somerville, any digging in the street for a private drain needs a licensed drain layer and a written permit from the City Engineer.
Sewer line replacement cost is the question that comes up when a Somerville basement floor drain backs up. In our 1900–1930 triple-deckers and two-families, the pipe from the house to the street is often original clay or cast iron, and after a century it cracks, sags or fills with roots.
The short answer: a camera inspection tells you whether you need a spot repair, a liner or a full dig, and that choice drives most of the price. Below is how the process works in Somerville, Cambridge and the rest of Greater Boston.
What drives sewer line replacement cost
Every lateral is different. These are the factors that move the number most:
- Length and depth. A deep line under a long front yard costs more than a short, shallow run.
- Where the break is. Under the basement slab, under the yard, under the sidewalk or out in the street are very different jobs.
- Method. Lining or bursting avoids most digging. A collapsed or badly sagging pipe usually has to be dug and replaced.
- Street work. Any opening in a public way adds permits, notices, traffic control and pavement repair.
- Access. On tight lots near Davis Square or Union Square, a small excavator and a dumpster may not fit without planning.
For a ballpark only, HomeGuide's national averages list $50 to $250 per linear foot for replacement, about $2,000 to $10,000 for a 40-foot line, and $90 to $250 per linear foot for cured-in-place lining. Those are national numbers. Greater Boston usually runs higher, and street work in Somerville adds more.
Step one: a sewer camera inspection
Never replace a sewer line on a guess. A licensed plumber runs a camera from a cleanout in the basement out toward the city main and records the whole run. HomeGuide lists a camera inspection at $125 to $500 nationally.
Ask for the video and the distance readings. A good report shows:
- Pipe material and any change in material along the run
- Cracks, offset joints, root intrusion and low spots (bellies)
- The distance from the cleanout to each defect, so you know if it is on your lot or under the street
Lining (CIPP) vs dig and replace
| Method | Best for | Watch out for |
|---|---|---|
| Cured-in-place lining (CIPP) | Cracked or root-filled pipe that still holds its shape | Will not fix a collapsed pipe or a deep belly |
| Pipe bursting | Replacing a run without a long open trench | Needs pits at both ends and a clear path |
| Dig and replace | Collapsed pipe, sags, or a new connection | Most disruption to yard, sidewalk or street |
In my experience, many older Somerville lines are a mix: part can be lined, and one bad section near the foundation or the curb gets dug. I ask the plumber to price both options from the same camera footage.
Who owns which part of the lateral in Somerville
Somerville's sewer ordinance (Sec. 11-155) defines a private sanitary sewer as one not owned by the city or the MWRA, including building sewer laterals on private property and the connection from the private sewer to the public system.
The ordinance also says that repairs of any drain laid from a house to the common sewer must be done by a licensed drain layer (Sec. 11-168). Before you budget, call the Somerville Water & Sewer Department and confirm how they treat the stretch under the street for your address.
Permits: drain layer, street opening and plumbing
This is where Somerville differs from many suburbs:
- Licensed drain layer. Openings into the common sewer and excavations in a street for a private drain must be made by a person licensed by the City Council (Sec. 8-41). Each drain layer posts a $10,000 bond and needs a written permit from the City Engineer for each job.
- Street opening notice. Under Sec. 11-143, the applicant must notify abutters within 300 feet by certified mail at least seven days before the permit is issued, and post the notice on site and at City Hall for seven days. The City can waive this in a true emergency.
- Sidewalk patch. A temporary sidewalk patch can stay no longer than 90 days before it is replaced with matching material.
- Plumbing permit. Somerville ISD says a licensed plumber must pull all plumbing permits, so homeowners cannot pull this one themselves.
- Tie card. The Water & Sewer Department's tie card checklist asks for the size, material and length of the new service, plus measured ties to cleanouts, bends and the connection at the city main.
Cambridge and Boston have their own rules, so the paperwork changes when you cross the city line. For permits on the rest of the house, see my Somerville building permit guide.
Need a hand?
If your Somerville, Cambridge or Medford basement drain is backing up, book a free walkthrough. I will coordinate the camera inspection, the licensed plumber and drain layer, and the permits, and send you a written line-item budget, usually within 48 hours.
Frequently asked questions
How much does it cost to replace a sewer line?
HomeGuide's national average is $50 to $250 per linear foot, or $2,000 to $10,000 for a 40-foot line. Greater Boston usually runs higher, especially when the street has to be opened.
Who is responsible for the sewer line in Somerville?
Somerville's ordinance treats building sewer laterals on private property and the connection to the public sewer as private. Call the Water & Sewer Department to confirm how the section under the street is handled for your address.
Is sewer pipe lining cheaper than digging?
Often, if the pipe still holds its shape. HomeGuide lists CIPP lining at $90 to $250 per linear foot nationally, but a collapsed or sagging pipe usually has to be dug and replaced.
Do I need a permit to replace a sewer line in Somerville?
Yes. Street and sewer openings need a licensed drain layer with a written City Engineer permit and abutter notice, and a licensed plumber must pull the plumbing permit.
Want a real number for your home? See my published prices and how I quote a job, and the towns I work in.
Mateus Magno founded Magno & Co in 2020. He is a licensed Massachusetts Construction Supervisor (CS-123658), registered Home Improvement Contractor (HIC #220484) and certified Lead-Safe Renovator Supervisor who has renovated and managed over $5 million in projects across Greater Boston.
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