Main Sewer Line Clogged: Symptoms and What to Do

What are the 5 symptoms of a clogged main sewer line?

The 5 symptoms of a clogged main sewer line are listed below.

• Several drains run slow at the same time.
• Toilets gurgle when a sink or washer drains.
• Water backs up into the tub when the toilet flushes.
• Sewage appears at the basement floor drain.
• Sewer odor fills the basement.

Is a clogged main sewer line an emergency?

Yes, a clogged main sewer line is an emergency once sewage backs up into the house.

What should you do first when the main sewer line clogs?

The 4 things you should do first when the main sewer line clogs are listed below.

1. Stop using water in the house.
2. Find the main cleanout in the basement or yard.
3. Keep away from any sewage.
4. Call a plumber to clear the main line.

When should you call a plumber?

You should call a plumber in the 4 situations below.

• More than one drain is slow.
• Sewage shows at a floor drain.
• The clog returns within months.
• Tree roots grow near the sewer line.

Related plumbing problems and next steps

How much does the plumbing repair cost?

The plumbing repair cost depends on the clog: main sewer line clearing costs $100–$800, according to HomeAdvisor. Sewer line repair prices and local plumbers are on the sewer line repair across Lancaster County page.

What is a related plumbing problem?

A related plumbing problem is tree roots in sewer line, and the tree roots in sewer line guide lists its causes and first steps.

Written and fact-checked by the Lancaster PA Plumbers editorial team using HomeAdvisor, EPA WaterSense and City of Lancaster data. Last updated October 29, 2026.