Sewer Backup in Your Home? What to Do in the First Hour

Step 1: Stop using water — everywhere

Every flush, faucet, shower, dishwasher and washing machine cycle adds water to a line that can’t drain. Tell everyone in the house. If an appliance is mid-cycle, stop it. If an ice maker or irrigation system ties into a drain, shut it off.

Step 2: Stay safe

• Keep people and pets out of affected areas. Sewage can carry bacteria and viruses.
• Wear rubber gloves and boots if you must enter, and wash thoroughly afterward.
• Watch for electrical hazards. Don’t step into water near outlets or appliances; shut off power to the area at the panel if it’s safe to reach.
• Ventilate by opening windows if you can do so safely.

Step 3: Find out where the blockage is

1. Locate your exterior sewer cleanout — usually a capped pipe near the foundation.
2. Loosen the cap slowly, standing to the side.
3. Full of water: the blockage is downstream — in your lateral or the public main.
4. Empty: the blockage is between the cleanout and the house.

Ask a neighbor or two whether they’re having problems. If several homes are affected at once, the public main is likely blocked.

Step 4: Call the right people

• Public main blocked (several homes): City of Whittier Public Works inside city limits; LA County Public Works for unincorporated areas like South Whittier and West Whittier–Los Nietos.
• Only your home: call us at (562) 358-3136. Your lateral is your responsibility to clear.

Step 5: Document before you clean

• Take photos and video of every affected area, including the water line on walls and damaged items.
• Note the time it started and what was happening (laundry running, heavy rain, guests).
• Keep receipts for service, cleanup and replacements.
• Call your insurer early. Many homeowners policies exclude sewer backup unless a specific endorsement was added — ask.

Step 6: Cleanup — know when to call professionals

Sewage water is treated by the restoration industry as the most contaminated category of water damage. Small, contained overflows on hard surfaces can sometimes be cleaned by a careful homeowner with protective gear and disinfectant. But if sewage has soaked carpet, drywall, insulation or subfloor — or covers a large area — a professional water-damage restoration company is the safer choice. Porous materials contaminated with sewage are usually removed rather than cleaned.

Step 7: Fix the cause so it doesn’t happen again

Once flow is restored, find out why it backed up. A thorough cleaning followed by a camera inspection will show whether the cause was grease, wipes, roots, a sag, or a broken section. Then you can decide between better habits, a maintenance schedule, or a repair.

Consider a backwater valve

If your lowest drains sit below the level of the upstream public manhole, a backwater valve can help keep sewage from the public main out of your home during a street-side blockage. The California Plumbing Code generally requires them for fixtures in that situation, and LA County notes they need regular maintenance to work. Ask whether your home has one — and when it was last checked.

Frequently asked questions

Related services

• Main Sewer Line CleaningSeveral drains backing up at once? Clear the main line fast and find out why it happened — before it happens again.
• Sewer Line Hydro JettingClean the lateral from your house to the street main — roots, grease and sludge removed, not just pushed aside.
• Recurring Drain Clog RepairSame drain, same clog, every few months? We find the cause behind the pattern and fix that — not just the symptom.

Sources

• LA County Public Works — Sewer Maintenance Customer Information

Precision Hydro Jetting — drain and sewer cleaning for Whittier, CA. This guide is general information, not a diagnosis of a specific plumbing system; conditions vary by property.