Water Heater Code Requirements in Texas: What Homeowners Should Know

When a water heater is replaced, the new unit has to meet the code in effect today, not the code from when the old one went in. That is why a replacement sometimes includes parts your old setup did not have. This guide explains who sets the rules in Texas and the code items that most often come up when a water heater is installed or replaced.

Who sets the rules in Texas?

There are two layers:

• The state licenses plumbers. The Texas State Board of Plumbing Examiners (TSBPE) administers the Plumbing License Law (Texas Occupations Code, Chapter 1301), which covers who may perform plumbing work, including water heater installation.
• Your city adopts and enforces the plumbing code and issues permits. The City of Arlington, for example, adopted the 2021 editions of the International Plumbing Code, International Fuel Gas Code, and International Residential Code, with local amendments, effective for permit applications starting January 1, 2023.

Because cities can amend these codes, the exact requirements can vary from one city to the next. The items below are common under the 2021 International codes, but your local inspector has the final say.

Common code items for a water heater installation

Temperature and pressure (T&P) relief valve Every tank water heater needs a T&P relief valve. Its discharge pipe must run full size to an approved location, such as outdoors near the ground or to an approved drain, without valves or threads on the end that could block it. This valve keeps the tank from building dangerous pressure or temperature.

Drain pan Where a leaking water heater could damage the building, such as in an attic, closet, or upstairs, code generally requires a pan under the unit with a drain line routed to an approved place. Many North Texas cities require a pan in more locations than that, so check local rules.

Thermal expansion control When water heats, it expands. If your home has a check valve, backflow preventer, or pressure reducing valve that keeps that water from pushing back into the city line, the system is "closed" and code requires a way to absorb the expansion, usually an expansion tank. Many newer and replaced installations in this area include one.

Elevation in garages (gas units) Gas water heaters in garages generally must have the burner or ignition source raised at least 18 inches above the floor, unless the unit is listed as flammable vapor ignition resistant. Units in garages also need protection from vehicle damage where they could be hit.

Venting and combustion air (gas units) Gas units must be vented correctly to carry exhaust, including carbon monoxide, outside. They also need enough combustion air. A unit in a small closet may need dedicated air openings. Switching to a different style of unit, such as tankless, often means new venting.

Gas shutoff and connectors A gas unit needs an accessible shutoff valve nearby, and the connection must use approved fittings and connectors.

Water shutoff An accessible shutoff valve on the cold water supply lets you turn off water to the heater without shutting off the whole house.

Access and clearances The unit must be reachable for service and replacement, with clearances the manufacturer requires. Attic installations have specific rules for access openings, walkways, and lighting.

Permits and inspections

In Arlington, the city lists water heater replacement and installation as work that requires a permit, and the work is then inspected. The inspection is what confirms the items above are done correctly. For more detail, read our guide on whether you need a permit to replace a water heater in Texas.

Why this matters when you replace a water heater

Bringing an older installation up to current code can add parts and labor to a replacement, such as a new pan and drain line, an expansion tank, a longer T&P discharge line, or venting changes. These are safety items, not upsells, and they are part of why the final price depends on your existing setup. Our water heater replacement and water heater installation pages explain how we approach each job, and our Arlington water heater replacement guide covers the full process. If a repair may be enough, our water heater repair in Arlington guide covers the common problems.

Frequently asked questions

Is an expansion tank required on a water heater in Texas? Code requires thermal expansion control when the water system is closed, for example when a check valve, backflow preventer, or pressure reducing valve is installed. In that case an expansion tank is the usual solution. Your local inspector makes the final call.

Does a water heater need a drain pan? Code generally requires a pan with a drain line where a leak could damage the building, such as in an attic or closet. Some cities require pans in more locations, so check with your city.

Where should the T&P relief valve drain? The discharge pipe must run full size, without valves, to an approved location such as outdoors near the ground or an approved indirect drain. It cannot be capped or threaded at the end.

Does Arlington follow the 2021 plumbing code? Yes. The City of Arlington adopted the 2021 International Plumbing Code, International Fuel Gas Code, and International Residential Code, with local amendments, effective for permits starting January 1, 2023.

Want it done to code?

Boost Air And Plumbing serves Arlington, Grand Prairie, and the surrounding North Texas communities. Call (817) 527-8883 or use the Book online button to schedule a visit. Learn more about our Arlington plumbing services.