Sewer Line Repair Pros
Get Quotes

Sewer Backup in the Basement: What to Do Right Now

Sewage rising out of a basement floor drain or the lowest toilet almost always means the main line is blocked, either in your own lateral or, during heavy rain, in the city's system. Stop using water first; every flush upstairs ends up on the basement floor.

Most main-line clogs clear with a cable machine for $100–$500, or with hydro jetting for $350–$1,400 when grease or roots are involved. Whether you or the city pays depends on where the blockage is, which a camera inspection ($125–$500) can document.

If this is unsafe or getting worse right now, don't wait — send an emergency request and it's flagged for priority routing to an independent local pro.

Send an emergency request

Tell us what's happening — emergency requests are flagged for priority routing.

Step 2 of 3The details

Where is it, and what's going on?

Hydro Jetting & Main Line Clog Clearing · Emergency — sewage backing up now

Free · No obligation · Independent local pros

What to do in the first 5 minutes

  1. Stop all water use in the house: no flushing, showers, laundry or dishwasher until the line is cleared.
  2. Keep everyone, especially children and pets, out of the affected area; treat the water as sewage.
  3. If water is near outlets, appliances or the furnace, shut off power to the basement at the panel, but only if you can reach the panel without standing in water.
  4. Note whether it's raining hard or neighbors have the same problem; that points to the city main, not your lateral.
  5. Call a sewer pro to clear the line, and call your city's wastewater or 311 line if the backup tracks with storms or affects the street.
Side view of a home's sewer line. The house drain leaves the basement, passes a capped cleanout beside the house, and runs as the sewer lateral under the yard, property line, sidewalk and street to a tap on the city main. Bars beneath show the homeowner owning the lateral from the house to the property line, the city owning the main, and the stretch from the property line to the tap varying by city.
Who pays depends on where the blockage is: the homeowner is responsible for the lateral on private property and the city for the main, with the stretch under the street varying by city.

Do not do this

  • Don't wade into sewage without boots and gloves; it carries bacteria and viruses.
  • Never stand in water to reach the electrical panel or unplug equipment.
  • Don't pour chemical drain cleaner into a backed-up main; it won't clear it and splashes onto whoever opens the cleanout.
  • Don't open a cleanout cap under pressure from the house side; sewage can surge out.

What's likely going on

Clog in your sewer lateral

Grease, wipes and debris build up where the line runs from the house to the street. A cable machine usually clears it; recurring clogs call for a camera look.

Tree roots in an older pipe

Roots enter clay and cast iron joints and catch everything that flows past. Root cutting typically adds $100–$600 to the clearing.

Storm surcharge in the city system

Heavy rain can overload the public main and push water back up into the lowest drains. A backwater valve, typically $1,000–$2,000, is the usual fix if it keeps happening.

Broken or bellied lateral

A cracked or sagging section holds water and solids. Repairs typically run $1,100–$4,100 once a camera shows where it failed.

Side view of a two-story house with a basement. Waste from an upstairs toilet and a first-floor sink drops down the main stack to the house drain under the basement slab, then out to the sewer lateral. A clog in the lateral just past the foundation stops the flow, so wastewater backs up the house drain and rises out of the basement floor drain, the lowest opening, pooling on the basement floor. The city main under the street is shown at right.
A blockage in your lateral and a storm-overloaded city main both push sewage back to the lowest drain. Rain or neighbors with the same problem point to the main.

Diagnose it now

What it typically costs

Snaking the main line typically runs $100–$500 and hydro jetting $350–$1,400; a camera inspection to document the cause is $125–$500. If the lateral is broken, repairs typically run $1,100–$4,100 (Angi) and full replacement $3,000–$15,000 (HomeGuide) depending on method and what's above the line.

Frequently Asked Questions

Who pays to fix a sewer backup in my basement?

It depends on where the blockage is. Most cities make the homeowner responsible for the lateral on private property, and some for the full run to the main. If the city main overloaded, file with the city and keep photos and the plumber's camera report.

Can I use my basement drains while waiting for a plumber?

No. Every drain in the house feeds the same main, so any water you use comes up at the lowest point. Hold off until the line is cleared.

Does homeowners insurance cover sewer backups?

Often not under a standard policy. Many insurers sell a separate water or sewer backup endorsement. Check your policy and call your agent before cleanup starts.

How do I stop sewer backups from happening again?

Keep grease and wipes out of the drains, have roots cut on a schedule if a camera shows them, and ask about a backwater valve if backups track with heavy rain.

The service that handles this

Hydro Jetting & Main Line Clog Clearing

Guidance only — independent local providers assess and price their own work. Last reviewed: October 28, 2026.

Sources for the cost figures

  • Angi: Sewer line replacement or repair costs (updated Jul 9, 2026) (third-party estimate)
  • HomeGuide: Sewer line repair and replacement cost (2026) (third-party estimate)
  • HomeAdvisor: Sewer main installation and replacement cost (2026) (third-party estimate)

Prefer to just talk to someone?

Send the short form — we'll route you to an independent local pro.

Request a Quote