What this covers
A tank water heater stores and heats a set volume of water, typically 40 to 80 gallons, with gas or electric heat. Installation starts with sizing to the household's peak demand and matching the fuel and venting in place. The plumber drains and removes the old unit, sets the new one on a pan, connects the supply with new flex lines or hard pipe, fits an expansion tank where the system is closed, runs the relief discharge line, connects the gas and vent or the circuit, and straps the tank where the local code requires it. Careful work ends with a leak check, a combustion or electrical check, and the temperature set.
When to call
- A tank more than ten to twelve years old, or rust at the base or fittings.
- Water that runs out faster than it used to, or never gets fully hot.
- Rumbling or popping from sediment, or rusty hot water.
- A puddle under the heater, which usually means the tank itself has failed.
What to expect
- Size and selectCapacity, fuel and recovery rate are matched to the household and the existing venting.
- RemoveThe old tank is drained, disconnected and hauled away.
- InstallThe new heater is set, connected, vented and fitted with pan, expansion tank and relief line.
- TestConnections are leak-checked, the burner or elements tested, and the temperature set.
Get a certified company
Look up a certified company by ZIP code. Every company's license, insurance and trades are verified before it is listed, and placement is never paid.
Questions people ask
What size tank do I need?
It depends on how many people use hot water at the same time and on the recovery rate. A plumber sizes by peak-hour demand rather than by household count alone.
Why an expansion tank?
When a home has a check valve or pressure regulator, heated water has nowhere to expand. The small tank absorbs that pressure so it does not stress the heater and fixtures. Many local codes require one.
Is a permit needed?
In most areas, yes, because the work involves gas or electrical connections and venting. The company pulls it and arranges the inspection.
Related: Tankless water heaters · Whole-house repiping · Water softener installation · All plumbing
This page describes what the service involves. The company you hire sets the scope, the schedule and the price, and your contract is with that company. We verify credentials and collect reviews from real jobs. We do not guarantee any company's workmanship. Safety steps are general guidance. When in doubt, leave the home and call 911.