Sewer Line Repair & Sewer Backups in Boston

What causes sewer line problems in older homes

Most building sewers in older Boston-area houses are cast iron inside the house and cast iron or vitrified clay outside it. Clay pipe was laid in short sections with joints every few feet, and tree roots find those joints, grow in toward the water, and form a net that catches everything that passes. Cast iron lasts a long time but rusts and scales from the inside, which narrows the pipe and eventually cracks it. Lines can also sag or separate as the ground settles, leaving a low spot that holds waste.

Some houses have Orangeburg pipe, made of layers of wood pulp fiber bound with adhesive and impregnated with coal tar pitch, which was used for about a century until the 1970s and tends to deform and collapse with age. And in every older house, decades of kitchen grease narrow the line. A camera inspection shows which of these you're dealing with.

Your line or the city's?

Responsibility usually splits at some point between the house and the main in the street, and where it falls varies by municipality. In Boston it is all yours: Boston Water and Sewer Commission maintains the main, but property owners pay for maintenance and repair of the entire lateral, from the basement to the main. Quincy, by contrast, puts the owner's share at the foundation to the edge of the sidewalk. Our area pages link to each town's department.

Boston owners facing a lateral repair should know about BWSC's Sewer Lateral Financial Assistance program: a one-time grant of up to $8,000 for an eight-foot relay or up to $6,000 for a full lateral line, where BWSC verifies the lateral is blocked, collapsed or leaking and the owner gets three estimates from BWSC-licensed and bonded contractors. A property can use it once every ten years, so check before you sign a contract.

If only your house is backing up, the blockage is almost always in your own line. If several houses on the street back up at the same time, or it happens during heavy rain, the public sewer may be overloaded or blocked, and you should report it to the city or town right away. In Boston, if you believe a backup came from a defect in the public system, Boston Water and Sewer Commission takes claims at (617) 989-7000.

Heavy rain can overload older sewers and push sewage back into unprotected basements. A backwater valve lets water out but not back in. BWSC's guidance notes that the state plumbing code requires one for buildings with fixtures below the top of the manhole cover of the sewer that serves them, that the property owner is responsible for installing and maintaining it, and that you should get three written estimates from licensed plumbers.

Camera inspections: see the problem before paying to fix it

A sewer camera inspection runs a waterproof camera on a cable from a cleanout down the line, recording what it sees and how far along the line each problem is. It answers the questions that decide the cost: is this roots or a collapse, one bad joint or the whole line, inside the house or under the sidewalk?

Ask for the video or screenshots. If you're quoted for a major repair or replacement, a recording lets you get a second opinion without paying for a second camera visit. A camera inspection is also worth paying for before you buy an older house.

Repair options: cleaning, spot repair, lining or replacement

Roots and buildup can be cleared with a cable machine or a high-pressure water jetter, which restores flow but doesn't fix the joint the roots came through; they will grow back, so many owners clean on a schedule. A single broken or root-invaded section can be dug up and replaced (a spot repair). When the line is failing along its length, the choices are full replacement by excavation, or trenchless methods: pipe lining, which cures a new resin pipe inside the old one, or pipe bursting, which pulls a new pipe through while breaking the old one apart.

Trenchless repairs avoid digging up a driveway, garden or sidewalk, but they aren't possible for every line, for example one that has collapsed or has severe sags. Excavation in the street or sidewalk needs permits from the city or town, which adds time and cost. Ask the plumber to explain why they recommend one method over another, using the camera footage.

Preventing sewer problems

Most of what ends up blocking a building sewer was flushed or poured. Keep wipes, paper towels and grease out of the drains, and if roots have been a problem before, ask the plumber how often your line needs cleaning; a routine cleaning is far cheaper than an emergency at midnight. If you're buying an older house, pay for a camera inspection of the sewer line before you sign.

Don't send clean water into the sewer either. Towns across Greater Boston prohibit sump pumps, roof downspouts and foundation drains connected to the sanitary sewer, because that stormwater overloads the system and causes backups in other people's basements. Quincy fines owners for it, Revere's sewer settlement with federal regulators is built around removing those connections, and Needham names illegal sump pump discharges as a source of the extra water in its sewers. If your sump pump discharges into a basement drain, ask a plumber to reroute it.

Cleaning up after a sewer backup

Treat everything sewage touched as contaminated. Boston Water and Sewer's cleanup advice is practical: wear rubber gloves, eye protection and boots, keep sewage away from your face, remove the water with a pump, wet vac or mop (never into the street or a catch basin), dry the area quickly and disinfect with a quarter cup of household bleach per gallon of water. Throw out soaked upholstered furniture and mattresses, and tell your insurer early, with photos, dates and receipts.

What sewer work costs

Clearing a main line is a modest bill; camera inspections add a little; spot repairs, lining and full replacements are major jobs priced by length, depth, access and permits. Get the camera inspection first and an itemized quote second.