Repair or Replace a Water Heater? How to Decide
Age, where the water is coming from and what the repair costs settle most cases in a few minutes.
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The short answer
Replace the heater if the tank itself is leaking, or if it is past about 10 years old and needs a repair that costs a large share of a new unit. Repair it if it is younger, the problem is a single part such as a thermostat, element, igniter or valve, and the tank is sound.
The U.S. Department of Energy puts the typical life of a storage tank water heater at 10 to 15 years. The lower end of that range is a useful line. Past it, every repair is a bet on an old tank.
Decide by symptom
Where the problem is tells you more than the age alone.
| What you see | Usually points to | Repair or replace |
|---|---|---|
| Water leaking from the tank body or the bottom | The steel tank has corroded through | Replace |
| Water dripping from a pipe fitting or the relief valve | A loose fitting or a valve that needs replacing | Repair, unless the tank is old and corroded |
| No hot water from an electric heater | Failed heating element or thermostat | Repair, if the tank is sound |
| Pilot will not stay lit on a gas heater | Thermocouple or gas valve trouble | Repair, if the tank is sound |
| Rumbling or popping noises | Sediment or scale in the tank | Flush first, replace if it keeps returning |
| Rusty hot water | Corrosion inside the tank or a spent anode rod | Depends on age, see below |
The half-of-replacement rule of thumb
A common rule among plumbers is that if a repair costs more than about half of a new heater, and the unit is past the middle of its life, replacement is the better buy. It is a rule of thumb and not a law, but it keeps you from paying for an expensive part on a tank that may fail next year.
The reverse also holds. A cheap repair on a heater under about eight years old is almost always worth doing. Ask the plumber to write down the repair quote and the replacement quote together so you can compare them.
How to find your heater's age
The serial number on the label encodes the manufacture date, and each brand uses its own format. The number often begins with a letter for the month and two digits for the year, but the code varies by brand, so check the manufacturer's site or ask the plumber. Photograph the label now. It saves time when you call and helps you track when the warranty ends.
Signs to plan a replacement
- The heater is 10 or more years old and needs a second repair
- There is rust at the tank base or around the fittings
- Hot water runs out much faster than it used to
- Water pools under the tank after every heating cycle
- Your energy bill for water heating has crept up
- The tank makes constant popping or rumbling that a flush does not fix
What a replacement includes
Replacement is not only the tank. A correct installation adds new connectors, a relief valve with a proper discharge pipe, earthquake strapping and, in many homes, an expansion tank. Our page on water heater installation and replacement describes each item, and a permit and inspection may apply.
If you want to compare a tank against a tankless model while you are replacing, see tankless vs tank water heaters first, since switching can change the gas line and venting.
When a repair is the smart move
Plenty of heaters fail from a single small part. A worn thermostat, a bad element or a stuck relief valve does not mean the tank is finished. If the heater is in the first half of its life and the tank is dry, a repair extends its use at a fraction of the price. Our water heater repair page lists the common faults and what each one costs to consider.
A leak is the exception. Any water that comes from the tank body, rather than from a fitting on top, is the end of that tank.
Costs beyond the tank
The price on the quote is only part of what a heater costs. A more efficient model uses less energy every month, and the yellow EnergyGuide label shows the estimated yearly operating cost. A cheaper tank that uses more gas or electricity can cost more over its life than a better one.
Warranty terms matter too. Many tank heaters come with a limited warranty on the tank, and the terms often do not cover labor. Read what is covered before you decide, and keep the paperwork with the model and serial numbers.
Questions to ask before you approve a replacement
- What size do you recommend for my household, and why?
- Does the price include strapping, a relief valve discharge pipe and an expansion tank if needed?
- Who pulls the permit, and is the inspection included?
- What does the warranty cover, and does it include labor?
- Will you haul away the old heater?
- How long will the house be without hot water?
Sizing matters
A heater that is too small runs out of hot water and works harder. One that is too large wastes energy keeping extra water hot. The first-hour rating on the label, which is how much hot water the heater can deliver in an hour of heavy use, is a better guide than the tank size alone. A plumber can match it to how many people use hot water and at what times.
Questions about this topic
The U.S. Department of Energy gives a typical life of 10 to 15 years for a storage tank heater. Hard use, sediment and water conditions can shorten that.
If the leak is from a fitting or a relief valve, often yes. If it is from the tank body, no. The tank has to be replaced.
Only for a very cheap fix. At that age, a larger repair rarely makes sense, and replacement gives you a warranty and better efficiency.
If there is a leak, close the cold inlet valve and shut off the gas or power. Then get repair and replacement quotes in writing.
Often yes. Ask the plumber who pulls the permit and whether inspection is included.
Related guides
Tankless vs Tank Water Heater: Which Is Right for You?
Tankless units last longer and save energy in many homes. They also cost more to install and can need a bigger gas line.
Water Heater Permit in Sacramento County: What You Need
A same-for-same replacement usually needs a plumbing permit. Here is what the permit and inspection cover.
Hard Water and Water Heaters in Sacramento: What to Know
Scale is the quiet cause of many heater problems. Here is how it forms and what to do about it.
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