If sewage is backing up into your home, stop using all water immediately — every flush, sink, and washing machine cycle adds to what’s coming back up. Keep people and pets away from the affected area, because sewage carries genuine health risks. Photograph everything before you clean anything, for insurance. Then call a plumber with camera equipment, because clearing the blockage without finding the cause means it happens again in the next storm.
The first hour, in order
1. Stop all water use — everyone in the house
This is the single most effective thing you can do in the first sixty seconds, and it’s the one people skip. If the line is blocked, every gallon that goes down a drain anywhere in the house comes back up at the lowest fixture. Tell everyone in the home. Stop the dishwasher and washing machine mid-cycle if they’re running.
2. Keep people and pets clear
Sewage backup is a biohazard, not just a mess. It can carry bacteria, viruses, and parasites. Keep children and pets out of the area entirely, and don’t walk through it and then through the rest of the house. If you have to enter the space, wear waterproof boots and gloves, and wash thoroughly afterward.
3. Shut off power to the affected area — from the breaker
If water is near outlets, appliances, or a water heater, cut power to that zone at the breaker panel. Do not wade into standing water to reach a switch or unplug something. If the panel itself is in the affected area, or you’d have to stand in water to reach it, stop and call an electrician or your utility.
4. Don’t use chemical drain cleaners
They don’t clear main line blockages — they’re designed for a local clog in a fixture trap, not a blocked lateral thirty feet underground. What they do accomplish is making the standing water caustic, which is a hazard for you and for whoever comes to work on it. If you’ve already used one, say so when you call. It genuinely changes how the technician approaches the job.
5. Photograph everything, before you clean
This is the step people most regret skipping. Insurance adjusters need to see the extent of the damage, and cleanup that happens before documentation can weaken or void a claim.
- The standing water at its highest point, with something for scale
- Every affected room, wide shots and close-ups
- Damaged flooring, drywall, baseboards, and belongings
- The fixture where it’s backing up
- Any visible water line on the wall
Take more than you think you need. Video walking through the space is also useful.
6. Call for emergency service — and use the right words
Say “sewage backup” when you call. It isn’t the same dispatch category as a slow drain, and using the specific term moves you up the priority list — particularly during a storm, when the phones are busy and triage is happening in real time.
Tell them whether sewage is still actively coming up, which fixtures are affected and on which floor, whether it started during or after rainfall, whether neighbors are having the same problem, and whether you’ve used chemical cleaner.
7. Call your insurer
Sewer and drain backup is frequently excluded from standard homeowners policies and sold as a separate rider. Find out which you have. If you’re covered, open the claim now rather than after cleanup — adjusters generally want to document before remediation begins.
What not to do
- Don’t start cleaning before photographing. It’s the most common and costliest mistake.
- Don’t run water to “test” whether it’s cleared. If it hasn’t, you’ve added to the problem.
- Don’t rent a drain snake and go in yourself. A main line blockage during a storm is frequently structural, and a rented machine can turn a repairable crack into a collapse.
- Don’t assume it’s over when the water recedes. Receding water means pressure equalized, not that the blockage cleared.
What happens after the water is gone
Once the immediate backup is handled, the important question is why it happened. If it followed heavy rain, the likely causes are groundwater infiltration through a cracked lateral, root intrusion, or municipal system surcharge. We cover those in detail here.
A camera inspection identifies which. That matters because the fix ranges from clearing a root mass to replacing a failed section of line, and those are very different jobs. Clearing the blockage without diagnosing it means you’re waiting for the next storm.
Contaminated porous materials — carpet, pad, drywall that wicked up sewage — generally need to come out rather than be dried. That’s remediation work, separate from the plumbing repair, and your insurer may have preferred vendors.
Preventing the next one
- Camera inspection of the lateral, especially if the home predates 1975
- Clear any drain that’s been running slow, before storm season rather than during it
- Consider a backwater valve if you’ve had a backup before, or your home sits low relative to the street
- Confirm downspouts and area drains don’t discharge into the sanitary sewer
- Know where your cleanout is, before you need to find it in the dark
Frequently asked questions
Is a sewer backup an emergency?
Yes. Sewage in the home is a health hazard and the damage compounds the longer it stands. It warrants same-day emergency response, not a scheduled appointment.
Can I use the toilet if only the shower is backing up?
No. They share the same line. Anything you send down any drain goes to the same blockage and comes back up at the lowest point.
Will my homeowners insurance cover this?
Often only with a specific sewer backup rider. Standard policies frequently exclude it. Call your insurer before cleaning up.
Why did it happen during rain?
Heavy rain saturates soil and pushes groundwater into cracked sewer lines, adding volume a compromised line can’t carry. It can also surcharge the municipal system. Rain is the trigger, not the underlying cause.
24-hour emergency service in North County San Diego. John Stevenson Plumbing, serving San Diego County since 1990. Call (760) 276-6690.
We service homes on municipal sewer. We do not service septic systems.