Sewer Backup in the House: What to Do First

If you have a sewer backup in the house, what to do first is stop using all water, keep people and pets away from the wastewater, and find out whether the problem is the City’s main or your own lateral. Then document the damage before cleanup begins, and get the line cleared and filmed before anyone decides on a repair.

Angeleno Sewer Line Repair arranges emergency clearing, camera inspection and repair through licensed, bonded and insured contractor partners across Los Angeles, Pasadena, Glendale and Burbank, and phones are answered 24/7. Below is the order that protects your health, your insurance claim and your budget.

Minute one: stop sending water down

A sewer backup happens because the line cannot carry flow away. Whatever goes down a drain upstream of the blockage comes back up at the lowest opening, usually a shower, tub, floor drain or ground-floor toilet. So the first step is to stop adding water.

Tell everyone in the building not to flush, shower, run the dishwasher or start laundry. Turn off an irrigation system if it feeds into the same area. If a washing machine or dishwasher is mid-cycle, stop it. In a duplex or small apartment building, tell the other units, because they share the line and their water ends up in your lowest drain.

If water is still rising with nothing running, it may be coming from outside the house, from a neighbor’s flow or a surcharged main. That is a clue for the next step.

Safety and health

Sewage carries bacteria, viruses and parasites. The CDC’s guidance for cleaning after a disaster says to wear rubber boots, rubber gloves and goggles if sewage is involved, to keep children and pets away from the affected area until cleanup is complete, to wash clothes worn during cleanup in hot water and detergent, and to wash up with soap and water afterward. It also says drywall and insulation contaminated with sewage should be removed and discarded.

Electricity is the other hazard. The CDC advises never turning power on or off or using an electric tool or appliance while standing in water. If wastewater is near outlets, a power strip, or a gas water heater or furnace, stay out of the water and shut off power at the panel only if you can reach it from a dry place. Otherwise, wait for help.

Open windows if you can do it without walking through the water. Do not mix bleach with ammonia-based cleaners; the fumes are toxic.

City main or your lateral?

In the City of Los Angeles, the City maintains the public sewer main in the street. The property owner is responsible for the lateral, the private pipe from the house all the way to that main, including the section under the street. That split decides who you call.

Signs the main is the problem: sewage is coming out of a manhole cover in the street, or several neighbors are backing up at the same time. Call LA Sanitation’s 24-hour Customer Care Center at 1-800-773-2489 and report it.

Signs the lateral is the problem: only your property is backing up, and the neighbors are fine. That points to a blockage or defect in your own line, and it is the owner’s to fix. The Bureau of Engineering also says root blockages are the owner’s responsibility whether they are on private property or in the public right-of-way. More on the split is in who is responsible for the sewer line.

If you live in Pasadena, Glendale, Burbank or unincorporated LA County, the same principle generally applies, but each has its own rules and its own number to call for a main problem.

Document before anything is cleaned up

Insurance decisions are made on evidence, and the evidence is easiest to collect before the mess is gone. Before cleanup, if you can do it safely:

• Take photos and video of every affected room, the water line on walls, and damaged belongings, with a wide shot first and close-ups after.
• Photograph where the water came from: the shower drain, floor drain or toilet that overflowed.
• Note the date and time you noticed the backup and the time you stopped water use.
• Keep receipts for anything you buy to limit the damage, and keep damaged items until the insurer says you can discard them, unless they are a health hazard.
• Ask whoever clears the line for a written note of what they found and where, and for the camera video if the line is filmed.

The California Department of Insurance’s residential guide notes that homeowners policies generally cover sudden and accidental water damage but often exclude water damage from seepage or leaks, wear and tear, and earth movement, and that endorsements can extend coverage. Whether your policy covers a backup depends on its own wording. The insurance guide goes through the usual exclusions and what to ask.

Clearing the line: what happens first

Once the cause is likely your lateral, the first job is to restore flow. That is done from a cleanout, the capped access fitting on the line outside the house, with a cable machine or a hydro jetter. Clearing a stoppage on its own does not need a permit in the City of Los Angeles; a permit comes into play when pipe is replaced or the street or sidewalk is excavated.

Typical budgeting ranges for Los Angeles-area projects, as of October 2026, put clearing or root cutting at $198–$1,016 and hydro jetting at $300–$800. They are budgeting ranges, not quotes, and an after-hours visit or a line with no usable cleanout can cost more.

Clearing is not a repair. It removes the blockage and tells you nothing about why the line clogged. The hydro jetting vs sewer repair guide explains the difference and when each one makes sense.

Film the line before deciding on a repair

After the line is flowing, ask for a camera inspection. The video shows whether the blockage was a grease plug in a sound pipe, roots entering at one joint, a belly that holds solids, or a broken or collapsed section. Those lead to very different decisions, from changing what goes down the drain to a spot repair to full replacement. A camera cannot see through standing sewage, which is why clearing comes first.

A standalone camera inspection typically runs $175–$800 in the Los Angeles area as of October 2026. In the City of Los Angeles, LA Sanitation offers a rebate of up to $300 toward a camera inspection while annual funds last. If the footage shows a defect, the signs of a broken sewer line guide explains how symptoms relate to what the camera finds.

Be cautious about agreeing to a large repair in the middle of the night. If the line is flowing again, the decision about lining, bursting or excavation can usually wait until you have the video and a second opinion. If the line cannot be cleared at all, or sewage is surfacing outdoors, that changes, and emergency sewer repair covers how urgent repairs are approached.

Cleanup is a separate job

The contractor who clears and repairs the sewer usually does not remove sewage-soaked carpet, cut out contaminated drywall, dry the structure or disinfect it. That is water damage restoration, a separate trade with its own equipment. Your insurer may want to approve that company or receive its moisture readings and photos.

Small, contained spills on hard floors are something many owners clean themselves using the CDC precautions above. Anything that has soaked into carpet, drywall, insulation or a subfloor generally needs to come out.

Preventing the next one

If the cause was grease, the fix is mostly behavior: keep fats, oils and grease out of drains. If it was roots, cutting them restores flow, but they return through the same open joint until that joint is repaired or lined. A belly or broken section keeps clogging until it is corrected.

Two pieces of hardware help. A usable cleanout outside the house makes clearing faster and keeps the work outside; see sewer cleanout installation. And a backwater valve, which lets flow out but closes against flow coming back from the main, is required in the City of Los Angeles when the lowest fixture sits below the next upstream manhole cover, and it needs an LADBS permit. Ask whether your house is one of them.

Keep the video, the invoice and any permit with the house records. If the line backs up again, that history makes the next diagnosis faster.