Main sewer line backup? Do this first.
When sewage comes up through a tub, shower or floor drain, every flush and every load of laundry makes it worse. These steps limit the damage and keep you safe until the line is cleared. If you'd rather skip straight to help, call (818) 669-9019 — we're open 24/7.
Updated October 2026 · Rooter Pros, Burbank-based mobile plumber · CSLB #917630
Grab these
For safety, not for fixing:
- Rubber gloves & boots — sewage carries bacteria
- Eye protection — the cleanout can spray when opened
- Towels or old sheets — to dam water away from carpet
- Phone camera — photograph everything for insurance
- Wrench — to loosen the cleanout cap
Emergency steps, in order.
Steps 1 and 2 stop it getting worse. Step 3 can relieve it. The rest keep you safe.
Stop all water use
Tell everyone in the house: no flushing, no showers, no dishwasher or washing machine. Turn off anything running on a timer. Every gallon that goes down a drain has to go somewhere — right now, that's your floor.
Keep people and pets away
Close off the affected room. Keep kids and pets out of the water. If sewage is near outlets, cords or appliances, don't walk through it — shut off power to that area at the panel only if you can reach the panel safely and dry.
Find the cleanout
Your main cleanout is usually a capped pipe outside near the foundation, or where the line leaves the house. See how to find your sewer cleanout.
Relieve the pressure carefully
Wearing gloves and eye protection, stand to the side and loosen the cap slowly — a little at a time. If sewage is backed up in the line, it may push out under pressure. Letting it drain outside at the cleanout is far better than letting it rise inside. Don't put your face over the opening, and don't remove the cap if the cleanout is indoors.
Don't pour chemicals
Drain cleaners won't clear a main-line blockage. They sit in the backed-up water and make it caustic for you and for whoever clears the line. If you already used one, tell your plumber.
Document and start safe cleanup
Photograph the water, the affected rooms and damaged items before cleanup. Wear gloves and boots, ventilate, and disinfect hard surfaces. Porous items soaked with sewage — carpet pad, upholstery, drywall — are often unsalvageable. For large spills, a water-damage restoration company is the safer call.
Is it your line or the city's?
This decides who you call first.
Possibly the public main
If neighbors on your street are backing up at the same time, the blockage may be in the public sewer. Report it to your city's sewer agency — in the City of LA, LA Sanitation (call 311); other cities have their own public works line.
Your lateral
If only your home is affected, the problem is almost always in your sewer lateral — the pipe from your house to the main — which is the owner's responsibility in most LA-area cities. That's who we clear.
Downstream of the cleanout
If the cleanout is full of water when you open it, the blockage is between the cleanout and the street. If it's dry, the clog is inside the house, upstream of the cleanout.
After it's cleared: find out why
A backup is a symptom. Roots, a belly, a broken section or grease buildup will cause the next one. We clear the line with drain cleaning or hydro jetting, then run a camera so you see the cause. If backups happen during heavy rain, ask about a backwater valve and read our rainy season prep.
When to call a pro.
Call right away if:
Sewage is coming up inside
That's a 24/7 call. We'll clear the line from the cleanout and tell you what caused it. Emergency plumber.
You don't have a cleanout
Without a cleanout, clearing the line may mean pulling a toilet. A new cleanout makes every future service easier and faster.
It's happened before
Repeat backups mean something structural — roots, a belly, a break. Read the signs your sewer line is failing.
Rooter Pros is open 24/7 — flat-rate pricing agreed before work starts.
Call (818) 669-9019Sewer backup FAQ
Straight answers, no sales pitch.
Can I still flush the toilet during a sewer backup?
No. Every flush adds more water to a line that can't drain, and it comes up at the lowest drain in the house — usually a tub, shower or floor drain.
Is sewage backup dangerous?
Raw sewage can carry bacteria and viruses. Wear gloves and boots, keep children and pets away, wash thoroughly after contact, and get professional cleanup for large spills.
Does homeowners insurance cover sewer backup?
It depends on the policy — some require a separate sewer backup endorsement. Photograph everything before cleanup and call your insurer to ask.
Why did my sewer back up during the rain?
Rainwater can get into sewer systems through broken lines, open cleanouts or illegal connections. In some areas, a backwater valve helps protect homes from backups out of the public sewer.
Sewage coming up right now?
If this doesn't work or you'd rather not mess with it, call (818) 669-9019. 24/7 emergency service · Free estimates · Upfront flat-rate pricing