What does water heater maintenance cost?

Q: What does water heater maintenance cost?

A tank flush costs $100 to $250 and an annual maintenance plan $100 to $300 a year, per This Old House (June 2026). An anode rod replacement, the item that actually decides how long the tank lasts, is $125 to $300 per Fixr (August 2025). A tankless unit needs descaling at $100 to $500 a year instead. Set against a $900 to $3,000 replacement, all of it is cheap.

What each job costs

Job	Cost	How often	Source
Tank flush, sediment removal	$100 to $250	annually, twice yearly in hard water	This Old House, Fixr
Anode rod replacement	$125 to $300	when worn, inspected every 3 to 5 years	Fixr
Annual maintenance plan from a plumber	$100 to $300 a year	annually	This Old House
Tankless descaling	$100 to $500	annually	This Old House
Tankless system cleaning	$100 to $200	annually	This Old House
Temperature and pressure relief valve replacement	$20 to $200	when it fails	This Old House

What the money actually buys

Two of these jobs do something specific to the life of the appliance. The rest are checks.

Sediment removal. Minerals settle at the bottom of the tank. This Old House names sediment buildup as one of the most common issues in tank-style water heaters, especially in hard water areas, and Fixr lists rumbling or popping noises from sediment as a sign of internal damage. On a gas unit the sediment layer sits between the burner and the water, so the burner works longer for the same result.

Anode rod replacement. The rod corrodes so the steel tank does not. This is the one item that decides whether a tank reaches the top of its published 8-to-12-year life or the bottom. This Old House puts it plainly: as a general rule, replacing a worn anode rod is far less costly than dealing with a failed water heater. Full detail on the anode rod page.

Everything else on the list is inspection: checking for leaks, testing the relief valve, reading the temperature setting. Valuable, but it is finding problems rather than preventing them.

The free part

This Old House's single most concrete maintenance figure costs nothing: set the thermostat to 120 degrees Fahrenheit, and for every 10 degrees you lower the temperature you can expect to save up to 5% in energy costs.

Against Fixr's running costs, that is real money. An electric tank costs about $720 a year to run, so 5% is roughly $36 a year, and a unit set 20 degrees too high is costing about $72 a year for nothing. A lower setting also reduces scalding risk.

The dial is on the side of the tank and moves with a flathead screwdriver.

The other free item: This Old House recommends insulating the hot water pipes, with the warning that pipes near the flue of a gas water heater need heat-resistant fiberglass wrap rather than foam, to avoid a fire hazard, and that valves and connections must stay accessible.

What you can do yourself, and where to stop

This Old House is unusually careful here, and the cautions are worth repeating because most maintenance advice omits them.

Reasonable to do yourself: check for visible leaks, adjust the temperature setting, add pipe or tank insulation. Flushing the tank and inspecting the anode rod are also manageable if the unit is in good condition and the fittings come apart easily.

Where to stop:

The relief valve. Testing it is not risk-free. On older units, mineral buildup can prevent the valve from resealing once opened, so forcing a test can create a leak where none existed. Richard Trethewey warns that interfering with a malfunctioning relief valve, or trying to block a persistent drip, can create a dangerous pressure situation inside the tank.
The drain valve. If it is clogged, hard to open or corroded, forcing it can cause leaks or stop it sealing again.
A heavily silted tank. A full flush can loosen sediment and create new problems rather than improving performance.
The anode rod in a tight space. If there is limited clearance above the tank or the rod will not loosen, forcing it can damage the unit or the connections around it.

The pattern across all four: on a well-maintained unit these jobs are routine, and on a neglected one they are how you turn a working water heater into a failed one. That is the argument for the $100 to $300 service plan on an older unit rather than a Saturday afternoon.

Is it worth it?

Our arithmetic, stated as such. A flush and an anode rod check once a year, at $100 to $250 plus a rod at $125 to $300 every few years, comes to roughly $150 to $350 a year averaged out. Over a 10-year life that is $1,500 to $3,500, which is the price of the water heater itself.

Put that way it looks like a poor deal, and we are not going to pretend otherwise. Neither source publishes a study showing how many years maintenance adds.

What tips it is the failure mode rather than the lifespan. This Old House prices water damage from a failed unit at $500 to $2,500 and emergency service at $200 to $500. Maintenance is also the visit where a corroding tank gets spotted before it lets go, which converts an emergency into a planned replacement.

Our honest reading: the anode rod and the temperature setting earn their keep on any tank. The annual professional flush is worth it in a hard water area and on a unit past about 6 years; on a young unit in soft water, it is closer to insurance than to savings.

Sources

Price figures are national US ranges from the sources above as of the date shown. Your local price depends on labor rates, permits and site conditions. Read how we get our numbers.