The first hour, in order
- Stop all water use.No flushing, showers, laundry, dishwasher or sinks. Every gallon you send down has nowhere to go but back up. Tell everyone in the house.
- Keep people and pets out.Close doors to the affected rooms if you can. Move valuables out of the path only if it is safe to do so.
- Check whether it is a drain or a supply leak.If clean water is spraying or pouring from a pipe, close the main water shutoff. A sewer backup is a drain problem, and stopping water use is the main step.
- Find the outdoor cleanout.Look for a capped pipe near the foundation or in the front yard. If it is overflowing, that points to a main line blockage. Do not force the cap if it is under pressure.
- Document.Take photos of the affected areas and note which fixtures backed up, in what order and when. This helps both the plumber and any insurance claim.
- Call a licensed plumber.Describe the backup, the fixtures involved and whether the cleanout is overflowing. Check the license at cslb.ca.gov when you can.
Where the backup shows up and what it may mean
| What you see | Likely location of the blockage |
|---|---|
| Only one sink or tub is slow | That fixture's drain or branch line |
| Tub or shower fills when the toilet flushes | Main line or a shared branch downstream |
| Lowest drain in the house overflows | Main sewer lateral |
| Outdoor cleanout overflows | Main lateral between the cleanout and the street |
| Cleanout dry but house drains back up | Between the house and the cleanout |
Do not
- Pour chemical drain openers into a backed-up main line.
- Keep plunging a toilet when other drains are also backing up.
- Use a household vacuum on sewage.
- Walk barefoot through affected areas or let children play nearby.
- Assume it is over once the water drains away; the blockage is usually still there.
After the line is cleared
Once flow is restored, ask for a camera inspection if one was not done. A backup in an older Fullerton home often traces to roots, a sag or buildup in the lateral, and knowing the cause helps prevent a repeat.
Cleanup is a separate task. Porous items such as carpet pad, rugs and drywall that soaked up sewage may need to be removed. For a large backup, a water damage or sewage cleanup specialist may be worth calling alongside the plumber. Check your homeowner's policy for what it covers before work begins.
Common questions
Should I shut off the main water valve during a sewer backup?
Stopping water use is the key step. Closing the main is a simple way to make sure no one runs water by mistake, and it is essential if a supply pipe is leaking.
Can I open the sewer cleanout myself?
You can look at it, but be careful. If the line is backed up, sewage may be under pressure behind the cap. Loosen slowly from the side, or leave it for the plumber.
Is a sewer backup the city's responsibility?
It depends on where the blockage is. The City of Fullerton maintains public sewer mains; the private lateral is generally the property owner's concern. Check with the city about where that responsibility ends for your property.
General information for Fullerton, not a quote or professional advice. In an emergency, call 911.