Seattle, WA · plumbing problem
Drains backing up in Seattle
Updated · Editorial team; not yet technically reviewed
Short answer
Seattle Public Utilities says grease from dishes and food waste causes about one-third of the city's sewer backups, with some 544,000 gallons clogging drains each month. It hardens and sticks to pipes over time. A single slow sink is usually grease in that branch; several drains backing up at once points to the side sewer.
What's different in Seattle
Grease rinsed down drains hardens and sticks to pipes, causing sewage backups, plumbing repairs and pollution in Puget Sound. [1]
About 544,000 gallons of grease clog Seattle drains every month, mostly from dirty dishes and food waste, accounting for about one-third of the city's sewer backups. [1]
Grease comes from meat, fish, butter, cooking oil, mayonnaise, gravies, sauces and food scraps. [1]
Grease or side sewer?
| Pattern | Likely cause |
|---|---|
| Kitchen sink only | Grease in the kitchen branch |
| Basement drain backs up, several fixtures slow | Side sewer blockage or roots |
| Neighbors backing up too | Public main: call SPU |
Keeping grease out
- Wipe plates and pans into the compost or trash before washing.
- Collect cooking oil in a container for disposal.
- Use sink strainers.
Related
You may also be dealing with
- SymptomSink not draining
- SymptomGurgling drains
- SymptomBasement flooding
- GuideWhy does my drain keep clogging?
Common questions
How much grease clogs Seattle drains?
About 544,000 gallons a month, according to SPU.
What share of Seattle sewer backups come from grease?
About one-third.
Which foods put grease in Seattle drains?
Meat, fish, butter, oils, mayonnaise, gravies, sauces and food scraps.
Does grease harm Puget Sound?
SPU says grease-related backups contribute to pollution in Puget Sound.
How do I tell grease from a side sewer problem?
Kitchen-only means grease in the branch; several fixtures means the side sewer.
Can Seattle food scraps go in compost instead of the sink?
Yes, SPU-style advice is to scrape plates into compost or trash before washing.
When should I call SPU about a backup?
When neighbors are backing up too.
Can roots cause Seattle drain backups?
Yes, in older side sewers; a camera shows them.
Does jetting clear Seattle grease clogs?
Yes, it scours grease off pipe walls.
Is a garbage disposal OK for greasy scraps?
No; grease passes through and hardens downstream.
More plumbing help in Seattle
- Sewer Backup in SeattleSeattle sewer backups: most backup calls trace to the privately owned side sewer, when SPU claims apply, and the backwater valves that protect basements.
- Backflow Testing in SeattleSeattle Public Utilities backflow testing rules: annual tests by your anniversary date, Washington-certified testers, reporting, and non-compliance charges.
- Sewer Line Repair in SeattleSeattle side sewer rules: owners maintain the entire side sewer, when you need an SDCI permit, emergency repair rules, typical permit fees, and shared lines.
- Water Line Repair in SeattleSeattle water lines: owners install and maintain the private line from the city union to the house, and how SPU's leak adjustments treat city-side and.
- Toilet Installation in SeattleSeattle toilet replacement: the Saving Water Partnership's $100 rebate for replacing pre-2004 toilets, free toilets for income-qualified homeowners.
- 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 SeattleLocal water, housing and climate conditions, and the calls Seattle 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 PhiladelphiaWhy Philadelphia drains back up: grease hardens in the lateral connecting homes to the sewer, sewage backs into houses, and how PWD says to dispose of it.
Sources (1)
- Seattle Public Utilities, Fats, oils and grease clog pipes · checked 2026-10-03