What does replacing a sewer line involve?

The short version

A sewer line replacement is a dig, a pipe job and a permit, done in that order by a licensed contractor you hire. The contractor runs a camera down the line to see what has failed, gets a plumbing permit, has the public utilities marked, then replaces the pipe from your house to the public sewer, in an open trench or by a trenchless method. Then the yard, walk or driveway is put back. In Fairfax County, repairs are inspected by the county's Building Inspections Branch,^[1] so ask your own building department when it inspects.

The pipe in question is usually called the sewer lateral: the pipe that carries sanitary waste from the plumbing system in a home or business to the public sanitary sewer main.^[1] Fairfax County describes laterals as typically 4 inches in diameter and public mains as typically 8 inches and larger,^[1] and Spotsylvania County puts laterals at 4 to 6 inches.^[2] Which part of that pipe is yours to replace depends on your locality; see who is responsible for the sewer line.

First, a camera inspection

Nobody should quote a replacement without seeing inside the pipe. Fairfax County lists the signs that a lateral may need repair as frequently clogged drains, odor of sewage, and basement backups during rain, and says the best way to assess a lateral's condition is a closed-circuit television (CCTV) examination.^[1] The camera goes in through a cleanout or a drain and records the whole run.

The video answers the questions that decide the job:

• Where the damage is. One cracked joint or root entry point can sometimes be repaired on its own. A line that is broken, crushed or full of roots along its length usually has to be replaced.
• What the pipe is made of. Older homes often have clay or cast iron, which break down differently from plastic.
• How deep it runs and what is on top of it. Depth, trees, driveways, walks and other utilities change both the method and the price.

Ask for a copy of the video and a marked-up sketch of where the problems are. If you are not sure what you are looking at, our page on the signs of a broken sewer line explains what each problem means, and a sewer scope inspection can be booked on its own.

Permits and the call to 811

Virginia's building code requires a permit before work that alters a building's sanitary drainage system,^[3] and an application for emergency work can be submitted by the end of the first working day after the work starts.^[3] Localities add their own steps. In Fairfax County, a repair or replacement on private property needs a plumbing permit from the county, work in a VDOT right of way needs a state permit as well, and repairs are inspected by the county's Building Inspections Branch.^[1] Ask your county or city building department what it requires before the job is scheduled.

The permit is the contractor's job. The Board for Contractors says: "The contractor should apply for and obtain any necessary building permits."^[9] It also warns that the permit holder becomes the general contractor and assumes responsibility for the overall job,^[9] which is why a contractor who asks you to pull the permit yourself is not doing you a favour.

Before any digging, Virginia's damage prevention law applies: "No person shall make or begin any excavation or demolition without first submitting a locate request to the notification center."^[4] That marks the gas, electric, water and communications lines that public utilities own. It does not mark your sewer lateral. Virginia 811 explains that the point of consumption for a sewer line is the sewer cleanout, which is usually located within 5 feet of the edge of the property,^[5] so the line between your house and the main at that cleanout will not be marked.^[5] The contractor finds it from the cleanout, with the camera, or with a locator.

Open trench or trenchless

There are two broad ways to put in new pipe.

Open trench. The crew excavates along the line, takes out the old pipe, lays new pipe at the right slope with proper bedding, and backfills. It is the most direct method and usually the way a sag or a collapsed section gets fixed. The cost is mostly in the digging and in putting back whatever was on top.

Trenchless. The pipe is replaced or rebuilt from the inside through one or two small pits. In lining, a resin-soaked tube is pulled or pushed into the old pipe and cured in place, leaving a new pipe inside the old one. In pipe bursting, a new pipe is pulled through while the old one is split apart around it. Trenchless work spares the lawn, trees and driveway, but it needs a line the liner or new pipe can follow; a fully collapsed section or a bad sag usually has to be dug out anyway.

Either way, the job also covers the connections at each end. Ask whether the price includes a new cleanout, the connection at the house, and the tie-in at the property line or main. Broken sewer laterals can allow tree roots or debris into the pipe,^[2] so a replacement is also the time to fix the joints that let roots in; see how to keep tree roots out of a sewer line.

Who does the work

A contractor you hire for this job should hold a licence that covers it. Virginia's plumbing contractor classification (PLB) covers piping for sanitary drainage facilities and the installation, maintenance, extension or alteration of sewerage systems.^[6] The Board also has an underground utility and excavating specialty (UUC) that covers water, gas and sewer connections to residential sites, subject to local ordinances.^[7] And the Board for Contractors requires a master tradesman licence as a condition of licensing a plumbing contractor.^[8]

Check before you sign. The Board warns that a license number in an advertisement or on a business card does not necessarily mean the contractor's license is valid;^[9] our guide to checking a contractor's licence shows how to look it up.

What to get in writing

Virginia law requires all licensed contractors to provide a written contract for residential work.^[9] For a sewer replacement, the contract should name the method, the length and material of the new pipe, who gets the permit, what happens if the crew finds rock or an unexpected problem, and exactly what restoration is included: grass seed or sod, concrete, asphalt, landscaping. On the deposit, the Board's rule of thumb is an initial deposit of no more than 10% of the total price or $1,000, whichever is less.^[9] For what drives the price, see what sewer line replacement costs in Virginia.

When to call a licensed pro

Call a licensed plumbing contractor as soon as you suspect the sewer line itself rather than one drain: several fixtures backing up at once, sewage in the basement, a wet or sunken patch over the line, or a sewage smell outside. Replacing a sewer line means trenching, working in and around raw sewage, connecting to the public system and passing a permit inspection, and it is not a job to take on yourself. If sewage is backing up now, start with the steps on our sewer backup page.

Find a licensed sewer pro

Loclis lists licensed businesses from Virginia's DPOR register with their licence number and class. Browse sewer line services, look up plumbers in Blacksburg, or read more plumbing answers. When you are ready, describe the job once and licensed local businesses quote it.