Tank or tankless
This is the biggest split. A tank heater stores hot water and is the simpler job. A tankless unit heats water as it flows, costs more to buy, and often asks more of the house: a larger gas line, special venting, and sometimes a new water or drain connection. Tankless is its own topic, so we cover it on the tankless water heater page.
Size and capacity
A tank is sized to how much hot water your household uses at the busiest hour, not to the number of bathrooms alone. A bigger tank costs more up front. A tank that is too small means cold showers and a heater that runs hard; one that is too big keeps more water hot than you need.
Gas or electric
Swapping like for like is the simplest path. Changing fuel changes the job. Gas needs a gas connection and proper venting. An electric unit needs a circuit sized for it. We do not do electrical work, so if the wiring has to change, your technician tells you at the estimate and an electrician handles that part.
Where the heater sits
A heater in a garage is quick to reach. One in a tight closet or an attic takes longer to drain, carry out and set, and the platform and pan under it may need work. Access is a real part of the labor.
Venting, shutoff and code items
A new heater is not just the tank. The pieces that make the install safe and to code add to the quote: the relief valve and its discharge line, an expansion tank where one is needed, a shutoff valve, a drain pan, and for gas units the vent connection and a gas shutoff. Old fittings that fail when disturbed get replaced too.
Permit and inspection
The City of Houston requires a permit for water heater replacement, pulled by a City-registered master plumber, plus an inspection. A low quote that skips the permit has not removed that cost; it has moved it to you. Ask every company who pulls the permit.
Houston water and the age of your home
Houston’s main water system averages about 7.9 grains per gallon, which the USGS scale calls hard. Hard water leaves scale in the bottom of a tank, which is why older tanks rumble. In older homes, the shutoff valves and connections around the heater are often as old as the heater itself, and replacing them is part of a clean job.
Brand tier and warranty length
Heaters in the same size can differ in build, parts and warranty length. A longer tank warranty usually costs more. Ask what the warranty covers, whether it includes labor, and who you call if it fails.
Sources: City of Houston Public Works 2025 water quality report; City of Houston Permitting Center; USGS water hardness scale. Updated November 2026.
