Grease is the single biggest cause of kitchen drain and sewer clogs — and the hardest to clear for good, because it coats the pipe rather than forming a single plug. Here is why, and what actually removes it.
Written bySteven Lockhart·Reviewed byMiguel Lopez, Owner & Licensed Plumber (CSLB #974600)·Last reviewedJune 2026 · 4 min read
Quick Answer
A grease clog in a drain forms when fats, oils, and grease (FOG) poured or rinsed down the kitchen sink cool, congeal, and coat the inside of the pipe. Over time the coating narrows the line and catches food and debris until it blocks. Snaking punches a hole through it, but grease re-coats fast; hydro jetting scours the grease off the pipe wall, which is what clears it for good. This is part of our complete guide to hydro jetting in West Los Angeles.
Kitchen grease buildup in the drain is the most common reason a kitchen line clogs. Warm grease goes down looking like a liquid, then cools and hardens against the pipe, building a layer that shrinks the opening and grabs every bit of food that follows. Because it lines the whole pipe rather than forming one plug, it is uniquely stubborn — and uniquely suited to hydro jetting, which washes the wall clean. This guide is part of our complete resource on hydro jetting in West Los Angeles.
A grease clog is a blockage formed when fats, oils, and grease (FOG) cool and coat the inside of a drain or sewer pipe, narrowing it and trapping debris until it blocks.
A restaurant grease line clog is the same problem at higher volume — commercial kitchens push far more FOG through their lines, which is why grease blockage removal there often needs scheduled jetting. The table shows why grease behaves differently from other clogs.
| Clog type | How it sits in the pipe | Best removal |
|---|---|---|
| Grease (FOG) | Coats the whole wall | Hydro jetting (scours) |
| Food debris | Caught in grease layer | Jetting clears both |
| Single object | One spot | Snaking/retrieval |
| Roots | At joints | Cutting + jetting |
FOG — fats, oils, and grease — is the grease drain problem in a nutshell, and it is a big enough issue that the U.S. EPA and local sewer agencies actively discourage pouring it down drains because it contributes to sewer overflows. At home, the fix is twofold: clear the existing buildup with hydro jetting, and keep it from rebuilding by scraping plates, collecting cooking grease in a container for the trash, and not rinsing oil down the sink. Prevention plus a clean line is what keeps grease clogs from coming back.
A homeowner’s kitchen sink backs up every few months despite repeated snaking.
New Pro hydro-jets the line, scouring years of congealed grease off the pipe wall, and reviews FOG habits with them.
The line drains fully again, and with simple grease-disposal changes the every-few-months clog cycle ends.
The Bottom Line
Grease clogs are stubborn because they coat the pipe rather than plug it — which is why snaking never lasts and hydro jetting does. We scour the line clean and help you keep FOG out of it. Call any time to clear a grease-clogged drain for good. More on our hydro jetting page.
Fats, oils, and grease (FOG) go down warm as a liquid, then cool and congeal, coating the inside of the pipe. The layer narrows the line and traps food and debris until it blocks. Because it lines the whole pipe, it is especially stubborn.
Because snaking punches a hole through the grease but leaves it coating the pipe wall, so it re-coats and clogs again. Hydro jetting scours the grease off the wall, which is what clears a grease line for good.
Hydro jetting — high-pressure water that washes the grease off the entire pipe wall, not just a hole through it — paired with better FOG habits to keep it from rebuilding. Together they break the recurring-clog cycle.
Don’t pour or rinse fats, oils, or grease down the sink. Scrape plates into the trash, collect cooking grease in a container to discard, and wipe greasy pans before washing. Local sewer agencies and the EPA recommend keeping FOG out of drains.
Yes — grease contributes to blockages and sewer overflows beyond your home, which is why agencies discourage pouring it down drains. Keeping FOG out of the drain protects both your line and the wider sewer system.
Often, yes — commercial kitchens push far more FOG through their lines, so scheduled hydro jetting is a common way to keep grease lines clear and avoid backups. The principle is the same as at home, at higher volume.
Written by the New Pro Plumbing content team and reviewed for technical accuracy by Miguel Lopez, owner and California-licensed plumber (CSLB #974600). Pipe lifespans are presented as typical ranges, not guarantees, and any pricing is confirmed in writing before work begins.
What's new: June 2026 — first publication.
Hydro jetting scours grease off the pipe wall, not just through it — flat-rate quote. Call any time.
