Sewer Backup in Philadelphia, PA: Causes & Fixes

Why is sewage backing up into my Philadelphia home?In Philadelphia, a sewer backup can come from your own lateral or from the city’s combined sewers during heavy rain. Because the homeowner owns the lateral, knowing the cause matters: dry-weather backups usually mean a clogged, root-filled or broken lateral; storm backups often point to the public system and a missing backwater valve. Because homeowners own their laterals in Philadelphia, a backup that keeps coming back in dry weather usually means the lateral needs repair, not just clearing.

Act now

A sewage backup is an emergency: it spreads quickly, contaminates everything it touches and gets worse every time a fixture is used.

Call (866) 417-0220

Why it happens in Philadelphia

Root-filled clay lateral

Old clay laterals under sidewalks admit roots that trap waste.

Combined sewer surcharge

Intense rain fills combined sewers and pushes water back into basements.

Collapsed or offset pipe

Century-old laterals settle and separate, stopping flow.

Grease in older kitchen lines

Scaled cast iron kitchen lines in row houses catch grease that eventually slows the main.

Signs to watch for

Dirty water rising in a basement floor drain
Sewage in a tub or shower when a toilet is flushed
Several drains gurgling or slow at once
Water coming out of the main cleanout
Sewer odor in the lowest level of the home

Emergency, or can it wait?

Call right away if…

Sewage in living space
Backup affecting all drains
Backup during a storm that keeps rising

Usually OK to schedule if…

A single slow drain with no sewage
Occasional gurgling with normal flow

What Philadelphia homeowners can check first

Does it happen in dry weather or only in storms?
Is the front-wall cleanout full of water?
Are neighbors seeing backups too?

Unfinished basement with exposed pipes — Stock photo: Oleksandr Chernobai / Unsplash

How our plumbers fix it

Open the cleanout to locate whether the blockage is inside or outside the house.
Clear the main line with a cable machine or jetter.
Run a sewer camera to find roots, breaks or sags.
Check for a missing or failed backwater valve if backups follow storms.

Sewer Backup in Philadelphia: questions

Will Philadelphia fix a sewer backup?

If the problem is in the city sewer, contact the Water Department. If it’s in your lateral, the repair is generally the owner’s responsibility.

Can a backwater valve help in Philadelphia?

Yes. A backwater valve can keep combined sewer water from backing into your basement during storms.

How do I know if the backup is my lateral or the city sewer?

A plumber can open your cleanout and camera the lateral. If your line is clear and the city sewer is full, the public system is the cause.

Does homeowners insurance cover a Philadelphia sewer backup?

Sewer backup coverage usually requires a separate endorsement. Check your policy, and photograph damage for any claim.

Next steps

Main Sewer Line CleaningThe main sewer line carries all of a home's wastewater to the city sewer or septic tank.Sewer Line Repair in PhiladelphiaSewer line repair fixes damage to the building sewer or lateral, the pipe that carries wastewater from a house to the public sewer main or septic system.Sewer Camera InspectionA sewer camera inspection sends a waterproof camera on a flexible push rod through the sewer lateral to record its condition.Hydro JettingHydro jetting cleans drain and sewer lines with water at high pressure, delivered through a hose with a nozzle that has rear-facing jets.Emergency PlumbingEmergency plumbing is urgent repair work for a problem that is actively causing water damage, a sanitation hazard, a gas risk or a total loss of water or drainage in a home.

National guide: Sewer Backup · Plumbing in Philadelphia