Philadelphia, PA · plumbing problem
Drains backing up in Philadelphia
Updated · Editorial team; not yet technically reviewed
Short answer
PWD says cooking grease doesn't break down in water. It hardens as it cools and builds up, often in the lateral that connects a house to the city sewer, until sewage backs up into homes. If one fixture is slow, it's a local clog; several backing up, starting in the basement, point to the lateral.
What's different in Philadelphia
Grease, oil and fats won't break down in water; grease that enters sewers builds up and eventually blocks them. [1]
As fats and oils cool they harden and clog pipes, often in the lateral connecting homes to the city sewer, and blocked sewers can back sewage up into homes and businesses. [1]
PWD says cooking fat such as deep-fryer oil and bacon grease should go in the trash, not down any drain. [1]
Symptoms in a Philadelphia home
- Basement floor drain or laundry tub backs up first.
- Kitchen sink slow, with a greasy film in the trap.
- Gurgling when the washer drains.
What to do
Stop running water
Especially laundry and dishwasher.
Clear the line
A plumber cables or jets from the cleanout; see hydro jetting.
Camera if it recurs
Breaks or sags in the lateral may qualify for PWD's HELP loan.
Rain or grease?
Backups only during storms point to sewer surcharge; see Philadelphia basement backups for PWD's free backwater valve program.
You may also be dealing with
- SymptomSink not draining
- SymptomGurgling drains
- SymptomBasement flooding
- GuideWhy does my drain keep clogging?
Common questions
Where do grease clogs form in Philadelphia homes?
Often in the lateral connecting the house to the city sewer.
Does cooking grease break down in water?
No, PWD says it builds up in pipes and sewers.
How should Philadelphians dispose of bacon grease?
In the trash, never down a drain.
Can grease cause sewage to back into my house?
Yes, blocked sewers and laterals can back sewage into homes.
Which drain backs up first in a rowhouse?
Usually the basement floor drain or laundry tub.
Is a storm-only backup a grease problem?
Usually not; it points to sewer surcharge, where a backwater valve helps.
Can PWD finance a broken lateral?
After a Notice of Defect, the HELP loan covers lateral repairs at 0%.
Does jetting work on Philadelphia laterals?
It clears grease well once a camera confirms the pipe is sound.
Why does my washer make the drain gurgle?
A partial blockage downstream is restricting flow and air.
Should I use chemical drain openers?
Not on lateral clogs; they rarely reach and make the line hazardous to open.
More plumbing help in Philadelphia
- Water Line Repair in PhiladelphiaPhiladelphia lead service lines: owner responsibility, free replacement during main work, the free ZIP-code pilot, and 0% HELP loans.
- Sewer Line Repair in PhiladelphiaPhiladelphia sewer and water line repair: PWD's HELP loan covers repairs at 0% interest over 60 months after a Notice of Defect.
- Basement flooding in PhiladelphiaWhy Philadelphia basements back up and how PWD's Basement Backup Protection Program installs free backwater valves and downspout changes for eligible homes.
- Leak Detection in PhiladelphiaIn Philadelphia, the owner is responsible for water piping from the city main, including the ferrule and curb stop. How leaks are found, and PWD's Notice of Defect.
- Frozen Pipe Repair in PhiladelphiaFrozen pipes in Philadelphia: keep the meter area above 40°F, trickle a faucet, shut off outdoor lines, check neighbors first.
- Backflow Testing in PhiladelphiaPWD backflow rules: test at installation, after any repair and yearly by a City-certified technician, file Form 79-770 within 48 hours.
- Drain backing up: the full guideWhen water rises in a tub, shower or floor drain from another fixture, the main line is blocked. How to confirm it, what to stop doing and how it's cleared.
- Plumbing in PhiladelphiaLocal water, housing and climate conditions, and the calls Philadelphia homes need most.
How other cities handle it
- Drains backing up in BoiseWhy drains back up in Boise homes: grease is the city's top cause of sewer clogs, older neighborhoods are most at risk, and what to check before calling.
- Drains backing up in HoustonWhy Houston drains back up: grease and wipes cause 70% of the city's sewer overflows, and overflows double when it turns cold. Symptoms, safe checks and fixes.
- Drains backing up in OrlandoWhy Orlando drains back up: grease builds up in home lines and the city's 800-plus miles of sewer. Symptoms, safe checks, the city's oil recycling, and fixes.
- Drains backing up in Los AngelesWhy LA drains back up: grease in kitchen lines and the city's 6,600 miles of sewer, the FOG program that cut overflows 94%, and what to check before calling.
- Drains backing up in San AntonioWhy San Antonio drains back up: grease causes nearly 70% of local sewer blockages, the surprising sources of it, safe checks, and how to get rid of grease.
- Drains backing up in SeattleWhy Seattle drains back up: grease causes about a third of the city's sewer backups, the foods it comes from, safe checks, and when it's the side sewer instead.
Sources (1)
- Philadelphia Water Department, Grease disposal guide for residents · checked 2026-10-03