Why Sewers Back Up in Houston After Heavy Rain (and How to Prevent It)

Houston gets intense rainfall, and when it does, some homeowners find water coming up through floor drains, tubs or toilets. Here’s why that happens and what you can do about it.

How Rain Gets Into the Sewer

Houston’s sanitary sewer is supposed to be separate from the storm drains, but rainwater still gets in. It seeps through cracked pipes and joints (infiltration) and flows in through openings like broken cleanout caps, low manhole covers and illegal downspout connections (inflow). During heavy storms that extra water can overload the system, and sewage can back up toward the lowest openings — often the drains in someone’s house.

Your Line or the City’s?

• Only your house backs up, even in dry weather — the problem is almost always your private sewer lateral: roots, grease or a broken pipe.
• Several houses on the street back up during heavy rain — the city main may be overloaded or blocked. Report it to 311.

How to Prevent Backups

• Install a backwater valve — a one-way valve on your sewer line that lets waste flow out but closes when sewage tries to flow back in. It’s the most effective protection for homes in low-lying or flood-prone areas.
• Keep the cleanout cap intact — a missing or broken cap lets rainwater pour straight into the sewer.
• Make sure gutters don’t drain into the sewer.
• Maintain your line — a camera inspection and periodic hydro jetting keep roots and grease from narrowing the pipe.
• Keep grease and wipes out of drains.

If It’s Happening Now

Stop using water, keep away from sewage, and see what to do in an emergency sewer backup. For repairs, see sewer backup repair in Houston.

Insurance

Standard homeowners policies often exclude sewer backup. A sewer/water backup endorsement is usually inexpensive and worth asking your insurer about.

Call (844) 212 9767 to get connected with a local plumber for sewer backup repair or backwater valve installation.