Digging and replacing a sewer line

When digging is the answer

• A collapse. Part of the pipe has caved in. Nothing can be lined past it until that section is replaced.
• A belly. The pipe sags and holds standing water. Waste settles in the low spot and the line keeps backing up. A liner follows the sag, so the pipe has to be re-laid to the right slope.
• A break too bad to line. The pipe is in pieces, or a joint has dropped so far that a liner can't get past it.

Keeping the dig small

The camera and a locator mark where the trouble is and how deep. The dig goes there, not along the whole line. Once the bad section is replaced, the rest of the run can often be lined from the same opening. One hole costs less to open and put back than a trench from the house to the street.

What a dig involves

• Marking buried utilities before anyone digs. Missouri's one-call system does this.
• Opening the ground, and breaking out paving or a walk if it sits on top.
• Replacing the failed section with new pipe at the right slope.
• Backfilling, then putting the surface back.
• Digging in a public street or sidewalk needs a permit and traffic control, which adds time and cost.

The connection at the main

The joint where your line meets the public sewer belongs to your line, not to the sewer district. MSD says so for the City of St. Louis and most of St. Louis County. A failed connection is usually reached by digging, because it is normally out of reach from inside the lateral.

Before the ground is opened

1. See the camera video, and the mark showing where and how deep.
2. Ask how much of the line will be replaced, and whether the rest can be lined.
3. Ask what is included in putting the surface back: fill, seed and straw, paving.
4. If your city has a lateral program, apply before the work starts. Clayton, Kirkwood and Webster Groves all want an application in before the repair starts. Every city's rules.

Questions owners ask

When does a sewer line have to be dug up?

When a section has collapsed, when it sags and holds water, or when it is so broken that a liner can't be pulled or pushed through. Lining can't fix any of those.

Does a dig mean replacing the whole line?

Not always. Often only the failed section is dug up and replaced, and the rest of the line is lined from the same opening.