Sewage Backing Up Into the House: What to Do Right Now
A sewer backup is one of the few plumbing problems where every extra minute genuinely makes it worse. The short list of actions that limit the damage until we arrive.
September 20, 2026 · 5 min read
Sewage coming up through a tub, a shower drain or a floor drain means the main sewer line has stopped carrying water away from the house. Everything that goes down any drain from this point on has nowhere to go except back up at the lowest opening. That is why the first rule is simple.
Stop putting water into the drains
No flushing, no showers, no dishwasher, no washing machine, no running the tap. Tell everyone in the house. If a washing machine or dishwasher is mid-cycle, stop it now, because the drain cycle at the end will push several more gallons into the house. This one step limits the size of the mess more than anything else you can do.
You do not need to shut off the main water supply for a sewer backup on its own. The supply side is not the problem. The exception is if a toilet is overflowing and will not stop, in which case close the valve behind that toilet.
Stay off the water
Raw sewage is a health hazard, not just an unpleasant one. Keep children and pets out of the room. Do not walk through it in bare feet or socks, and do not use towels and bath mats that touched it for anything else afterwards. If it has reached carpet, that carpet and pad will almost certainly need to come out; do not try to dry it in place.
Find the outside cleanout
Most homes in Rockwall, Collin, Dallas and Kaufman counties have a sewer cleanout in the yard, usually near the front of the house where the line heads for the street. It is a capped pipe at ground level, typically white PVC three to four inches across, sometimes in a small round box. If sewage is standing around it or the cap has been pushed off, the blockage is between the cleanout and the city main. If the cleanout is dry, the blockage is in the house side.
If you can locate it safely, you can loosen the cap so the line relieves into the yard rather than the house. That is a mess outside instead of inside, which is a trade worth making. Do not do this if the cleanout is right beside a door or a walkway that people will use.
What we do when we arrive
- Open the cleanout and clear the blockage with a cable, then jet the line if the cable reveals grease, scale or roots.
- Run a camera to find out what caused it. A wipe plug in a good line is a one-off. Roots, a belly or a collapsed section will do it again.
- Give you a straight answer on whether the line is sound or needs repair, with the footage to show you.
- Confirm every fixture drains before we leave.
Cleanup and insurance
Photograph everything before you clean, including the water line on the walls and any damaged belongings. Many homeowner policies cover sewer backup only through a separate endorsement, so check yours before assuming either way. For anything beyond a small hard-floor area, a remediation company is the right call, because sewage in drywall and subfloor is not something a mop resolves.
Why it happened
In our area the usual causes are wipes and grease in a line with something to catch on, tree roots in an older clay or cast iron lateral, and bellies where the expansive clay has let a section of pipe settle. Heavy rain can also surcharge the city main and push flow back toward homes with low-set drains. The camera pass tells us which it was, and that decides whether the fix is a habit change, a maintenance schedule or a repair.
Family-owned, based in Rockwall, licensed and insured. TX Master Plumber TXM11693. (469) 338-5533, any hour.
Frequently asked
Should I turn off the main water valve during a sewer backup?
Not usually. The backup comes from the drain side, not the supply. Just stop using every drain in the house. Only close a supply valve if a toilet is actively overflowing.
Can I pour drain cleaner down to clear it?
No. It will not clear a main-line blockage, and it leaves caustic liquid sitting in the pipe that whoever opens the cleanout has to deal with. It also does nothing against wipes or roots.
Is a sewer backup covered by insurance?
Often only with a specific sewer or water backup endorsement. Check your policy. Either way, photograph everything before cleanup.
Will it happen again?
That depends on what the camera finds. A clean line that only blocked because of what went down it should be fine. Roots, bellies and broken joints need a plan, and we will show you the footage so you can see why.