Houston plumbing facts

Texas plumbing companies must put their responsible master plumber's license number, starting with M, MPL or RMP, on both sides of service vehicles in letters at least 2 inches tall.

Source: 22 Texas Administrative Code § 367.10

Proposals and invoices from a Texas plumbing company must show the responsible master plumber's name and license number and the words "regulated by the Texas State Board of Plumbing Examiners."

Source: 22 Texas Administrative Code § 367.10

The state plumbing board tells consumers to get the name of the company's responsible master plumber, look up that license, and confirm it is current with a certificate of insurance on file.

Source: TSBPE Consumer Information

The Texas State Board of Plumbing Examiners does not regulate what plumbers charge. It advises getting several written estimates and warranties.

Source: TSBPE Consumer Information

Texas plumbing licenses renew every year and require 6 hours of continuing education. An apprentice holds a registration, not a license, and must work under a licensee's supervision.

Source: TSBPE License Types

Houston's current plumbing code is the city's amendments to the 2021 Uniform Plumbing Code, part of the 2021 Houston Construction Code that took effect January 1, 2024.

Source: Houston Permitting Center, Codes

In Houston, replacing a water heater requires a plumbing permit and inspection, and the permit must be pulled by a master plumber registered with the city.

Source: Houston Permitting Center, Water Heater permit

Under Houston's code amendments, clearing a stoppage or repairing a leak is exempt from a permit only when no valves, pipes or fixtures are replaced or rearranged.

Source: Houston Amendments to the 2021 UPC

Texas law lets owners do plumbing in their own homestead without a license, but Houston still requires a Homeowner's Plumbing Permit and an inspection.

Source: Houston Permitting Center, Homeowner's Plumbing Permit

Houston's amendments require PVC Schedule 40 for building sewers 6 inches and smaller, and bar galvanized pipe in or under slabs.

Source: Houston Amendments to the 2021 UPC

Several suburbs use different codes from Houston. Pearland, for example, has adopted the 2021 International Plumbing Code with local amendments.

Source: City of Pearland, Adopted Building Codes

Most near-surface soils in Greater Houston are expansive clays, chiefly the Beaumont Clay, which shrink and swell with moisture. That movement can rupture underground pipes connected to a slab.

Source: University of Houston CIGMAT (K. Tand, 2008)

Seasonal moisture changes in Houston's expansive clays can reach 15 to 20 feet or more below the surface.

Source: University of Houston CIGMAT (K. Tand, 2008)

After Winter Storm Uri in February 2021, Houston Public Works estimated that about a quarter of its customers had a leak on their property.

Source: Houston Public Works, Winter Storm Relief briefing

During the 2021 storm, Houston Public Works logged more than 11,000 water service calls, and about 50,000 single-family accounts showed either no flow or constant flow.

Source: Houston Public Works, Winter Storm Relief briefing

Houston credits water lost to leaks from freezing, settlement, corrosion or wear: 100% if repaired within 30 days, 75% within 60 days, and 50% after that.

Source: Houston Water Bills, Leak Adjustment Request

Houston Public Works says grease clogs and wipes cause 70% of the city's sanitary sewer overflows, and that grease-related overflows double when temperatures drop.

Source: Houston Public Works, Protect Our Pipes

When Hurricane Harvey dropped about 51 inches of rain in 2017, 18 of Houston's 39 wastewater plants went underwater and about 30% of the collection system flooded for nearly a week, according to city officials quoted in trade press.

Source: Municipal Sewer & Water (2018)

Houston's main water system averaged 135.5 ppm total hardness in the 2025 water quality report, with a range of 43.5 to 229 ppm. That is about 7.9 grains per gallon (our conversion).

Source: 2025 Houston Water Quality Report

About 90% of Houston's main-system water is surface water from Lake Livingston, Lake Conroe and Lake Houston; Kingwood and smaller systems run on groundwater.

Source: 2025 Houston Water Quality Report