Drain clogs and sewer line problems in Houston

Clog or sewer line? Read the symptoms

What you notice	Likely cause	Typical first step
One sink, tub or toilet is slow	A local clog in that fixture’s drain	Drain cleaning (snake or cable) at that fixture
Kitchen sink keeps clogging	Grease buildup in the kitchen branch line	Cleaning the line, then changing what goes down the drain
Toilet flush makes the tub gurgle or rise	The main line is partly blocked	Clean the main from a cleanout, then a camera inspection
Several fixtures back up at once, or sewage appears in the lowest drain	Main sewer line blockage, roots, a sag, or a broken pipe	Stop using water and call for main-line service
Wet, sunken or unusually green patch in the yard along the sewer path	A leak or break in the buried line	Camera inspection and location

Why Houston drains clog

Grease and wipes. Houston Public Works says fats, oils and grease, along with wipes, cause 70% of the city’s sanitary sewer overflows. It also says grease-related overflows double when temperatures drop, because grease hardens in cold pipes. The city’s advice: pour grease into a container, cool it, and throw it in the trash. Flush only toilet paper and human waste. “Flushable” wipes still belong in the trash.

Roots and shifting soil. Most of Greater Houston sits on expansive clay that swells when wet and shrinks when dry. Older clay and cast-iron sewer lines can crack or separate at joints as the ground moves, and roots find those openings. See the slab leak guide for more on soil movement.

Floods. During Hurricane Harvey in 2017, city officials told trade press that 18 of 39 wastewater plants went underwater and about 30% of the collection system flooded for nearly a week. When the public system is overwhelmed, sewage can push back toward homes through the lowest drains.

What a plumber should do before quoting a big repair

1. Clear the line, usually through an outdoor cleanout.
2. Run a camera down the line to see the problem, its depth and its distance from the cleanout. Ask to see the footage or get a copy.
3. Locate the problem from the surface before any digging. Anyone digging should contact 811 at least two days ahead. It’s free, and homeowners can use it too.
4. Give options in writing: spot repair, section replacement, full replacement or a trenchless method, each with its price and warranty.

Hydro jetting uses high-pressure water to scour grease and roots from inside a pipe. It is useful for recurring grease clogs. It can be the wrong tool for pipe that is already badly cracked, which is one more reason the camera inspection should come first.

Houston’s rules for sewer repairs

Houston’s plumbing code, the city’s amendments to the 2021 Uniform Plumbing Code, sets a few rules that affect your options and quotes:

• Permits. Clearing a stoppage or fixing a leak is permit-exempt only if no valves, pipes or fixtures are replaced or rearranged. Replacing sewer pipe needs a permit and inspection.
• Material. Building sewer pipe 6 inches and smaller must be PVC Schedule 40.
• Trenchless methods. Pipe bursting and lining are allowed when they use listed ASTM methods. They are not allowed on cast-iron pipe, and liners may not be installed in collapsed or compromised pipe.
• Abandoned lines. An abandoned sewer must be plugged within 5 feet of the property line.
• Roof drains and downspouts. Connecting these to the drainage system needs its own plumbing permit.

Suburbs set their own rules. Sugar Land, for example, lists permits for exterior sewer line repair or replacement and for drain repairs under the home.

Your line, or the city’s?

The private sewer line on your property is generally the owner’s responsibility, and the main in the street belongs to the utility. The exact dividing point depends on how your connection was built. Before paying for work near the street or curb, call Houston 311 or your MUD and ask where your responsibility ends. We could not confirm a single published dividing line for every Houston property.

Homes far from public sewer lines may have a septic system. In unincorporated Harris County these need a county permit, and the county suggests pumping every two to three years.

Backwater valves for flood-prone homes

A backwater (backflow) valve on the building sewer helps stop sewage from flowing back into the house when the public system surges. Gate-style valves seal tightly but must be closed by hand. Flap or check valves close automatically but seal less tightly. Installing one changes your plumbing, so it should be done by a licensed plumber. In Houston it needs a permit.

Questions to ask

• Can I see the camera footage, and where exactly is the problem?
• Is this pipe cast iron, clay or PVC? Does that rule out trenchless repair?
• Does the job need a permit, and will you pull it?
• What warranty covers the repair, and does it cover the whole line or only the section you fixed?