Step one: count the drains
| What you see | What it likely means | First move |
|---|---|---|
| One sink or tub drains slowly | Local clog in that fixture's trap or branch | Plunge or snake that fixture |
| Two fixtures on the same floor drain slowly | Clog in a shared branch | Try a cable, call if it persists |
| Lowest tub or floor drain fills when you flush | Main line restriction | Stop water use, call |
| Gurgling in several drains | Vent or main line problem | Call |
If the answer is the last two rows, stop. Adding water to a blocked main line pushes sewage to the lowest opening in the house. Our sewer line cleaning page explains the emergency path.
What works for local clogs
A cup plunger on sinks
Block the overflow opening with a wet rag so the pressure goes down the drain.
A flange plunger on toilets
The extended flange seals the bowl outlet and pushes the clog through.
A drain snake or hand auger
It reaches a few feet down and pulls out hair and soap clogs.
Remove and clean the trap
A bucket under the P-trap catches the water, and the clog is often right there.
Be gentle with plastic parts. Overtightening a slip nut cracks it, and a stuck fitting is worth a call.
What to avoid
- Mixing drain cleaners. Chemical reactions can release harmful fumes.
- Pouring a caustic cleaner into a standing clog. It sits and can burn skin during repair.
- Using a cable machine on a pipe you do not know. A wrong head can tear a hole.
- Flushing wipes labeled flushable. They do not break down like paper.
- Pouring cooking grease down the drain, even with hot water.
Chemical cleaners are the biggest mistake. They rarely clear a serious clog, and they harm the plumber who arrives next. If you have used one, tell us before we start.
Kitchen clogs are usually grease
Fat cools and sets inside the pipe, trapping food. It builds in layers over months, so the clog feels sudden but is slow. A cable can punch a hole, and the grease returns. A hydro jetting pass cleans the pipe wall, and a camera shows whether a low spot is holding the water.
Prevention is simple. Scrape plates into the trash, wipe pans, and pour cooled grease into a can. A disposal does not make grease disappear. See our drain cleaning page for the next step.
Bathroom clogs are usually hair
Hair wraps around the pivot rod and collects soap. A hair catcher in the tub prevents most of it. For a stopped tub, remove the stopper, pull out the hair mat and rinse the opening. If the tub still drains slowly, the clog is deeper.
When it keeps coming back
A clog that returns every few weeks points to something the snake does not solve: roots, a belly in the pipe, scale or a partial collapse. That is the moment for a camera. It is cheaper to see the cause than to clear the same blockage a fifth time.
A simple weekly routine that prevents most clogs
- Run hot water for a minute after each kitchen sink use to move residue along.
- Put a strainer in the kitchen sink and a hair catcher in each tub or shower.
- Scrape pans and plates into the trash before washing.
- Once a month, pour a kettle of very hot, not boiling, water down plastic pipes to loosen soap film.
- Run the garbage disposal with cold water and give it time to clear before turning the water off.
None of this replaces a cleaning when a line is already restricted. It does keep a healthy line healthy, and it keeps small problems from becoming the kind of clog that needs a camera.
Guidelines for chemical cleaners
Follow the label guidelines on any drain product, never mix two products, and keep them away from children. Poison control guidance and the California Plumbing Code, which is based on the Uniform Plumbing Code (UPC), both assume a drain is cleared mechanically wherever possible.
Pleasant Hill: trees, laterals and the district
Central San, which serves Pleasant Hill, says root intrusion is the leading cause of sewer backups and advises professional inspection or cleaning at least every other year when trees are near your lateral. It also says the property owner is responsible for the whole private lateral.
The district recommends an overflow protection device on the cleanout, installed by a licensed plumber and kept clear of dirt or plants. If your home has none, ask about adding one.
Neighbors can read the Concord page and the Lafayette page for local notes.
Local questions
Call when several drains are slow, the lowest drain fills when you flush, or a clog keeps returning.
It may help with a light film. It rarely clears a serious blockage.
They can damage old pipes and harm the plumber who arrives next. We advise against them for standing clogs.
Grease and food residue build up inside the line. A jetting pass cleans the pipe wall.
A device on the cleanout that sends a backup outside the house. Central San recommends one.
Still have a question about your situation? Call (855) 575-2890 any hour and describe what you are seeing.