How to Tell How Old Your Water Heater Is (And When to Replace It)
How old is my water heater? Decode the serial number, learn how long tank, tankless and heat pump units last, and when to repair or replace. 2026 costs.
In this article
- Why water heater age matters
- Find the label and the serial number
- How long water heaters last
- When to repair and when to replace
- The anode rod: a cheap way to add years
- What a replacement costs
- Permits, standards and incentives
- How this varies by region
- Does insurance cover a failed water heater?
- Track yours in Steadwell
- Frequently asked questions
Quick answer: Read the serial number on the rating plate and decode the first few characters for the build date. A tank water heater typically lasts 8 to 15 years, so start planning a replacement at about 10 years, and check the anode rod every few years to get the most from it.
Why water heater age matters
A tank water heater typically lasts 8 to 12 years according to HomeGuide, and the U.S. Department of Energy puts storage models at 10 to 15 years. After that, the odds of a failure climb every year, and a failed tank can release tens of gallons of water into your home before anyone notices. Knowing the age lets you replace it on your schedule, not during a flood.
Many homeowners have no idea how old theirs is, especially if the heater came with the house. The answer is printed on the unit.
Find the label and the serial number
Look for the rating plate on the side of the tank, usually near the top or about chest height. It lists the model number, the serial number and often the capacity and warranty term. Take a photo of it so you never have to crawl back into the closet or garage. If you plan to look it up later, our guide to finding any appliance's serial number covers other brands.
The build date is encoded in the serial number. The formats below come from the manufacturers and from InterNACHI's water heater dating chart. Formats change by brand, model line and year, so treat a decoded date as an estimate.
- Rheem and Ruud: the first four digits are the month and the year. A serial starting 0719 was built in July 2019.
- A.O. Smith: the second character is a letter for the month (A is January) and the third and fourth are the year. A serial starting AB22 was built in February 2022.
- State: the first character is a letter for the month (A is January) and the next two digits are the year. A serial starting C22 was built in March 2022.
- American and U.S. Craftsmaster: the first two digits are the year and the next two are the week. A serial starting 2206 was built in the sixth week of 2022.
- Bradford White: the first letter is the year and the second is the month. Bradford White's chart repeats on a 20-year cycle (A means 2004 or 2024) and skips some letters, so decide which cycle fits your home. A is January, and the letter I is skipped for months.
If the code does not give a believable date, or your brand is not listed, enter the serial number on the manufacturer's warranty-lookup page or call them. A.O. Smith's rating plate also carries a QR code that opens the unit's model, serial number and warranty status.
How long water heaters last
- Tank water heaters: 8 to 12 years (HomeGuide), up to 15 (DOE)
- Heat pump (hybrid) water heaters: about 10 to 15 years (DOE), with a higher price and lower operating cost
- Tankless water heaters: 15 to 20 years (HomeGuide), about 20 (DOE)
Water quality matters. The U.S. Geological Survey notes that hard water is prevalent in the east-central and western United States, and that heating it forms scale that can shorten the life of equipment and raise heating costs. If you hear popping or rumbling when the heater runs, that is usually sediment.
When to repair and when to replace
For a newer unit with a minor problem, such as a failed thermostat or heating element, a repair usually makes sense. Angi suggests considering replacement once a unit is 8 to 12 years old and developing problems, and Consumer Reports' general rule for appliances is that a repair costing more than half the price of a new one is probably not worth it.
Watch for these warning signs:
- Rumbling or popping sounds from sediment buildup
- Rust-colored hot water
- Visible corrosion or rust around the base or fittings
- Water pooling under or around the tank
- Not enough hot water, or water that never gets hot
Any leak from the tank itself means the tank has failed. Shut off the water supply to the heater, shut off the power or gas, and call a plumber.
The anode rod: a cheap way to add years
An anode rod is a metal rod inside the tank that corrodes first so the tank lining does not. Once it is used up, the tank itself starts to rust. Angi puts a new rod at about $20 to $50 and recommends replacing it at least every five years, with a plumber's labor typically around an hour. Many pros suggest inspecting it every few years, sooner in hard-water areas.
Flushing the tank once a year to clear sediment is a common maintenance step too. Check your owner's manual for the manufacturer's schedule, and keep the setting at 120 degrees Fahrenheit, which the Consumer Product Safety Commission recommends to reduce scald risk.
What a replacement costs
HomeGuide's January 2026 national ranges for installed cost are below. Your price depends on size, fuel type and how easy the installation is.
Removing and disposing of the old unit runs about $75 to $500 if it is not included, and HomeGuide lists permits and inspections at about $50 to $200.
Permits, standards and incentives
Permits: Permits are required in most jurisdictions, even for a like-for-like swap. Your plumber normally pulls the permit, and an inspection may follow. Rules differ by city and county, so check with your local building department and ask your contractor to confirm the permit is in the quote.
Federal efficiency standards: The Department of Energy's 2024 rule sets new minimum efficiencies for most residential water heaters manufactured on or after May 6, 2029, and DOE expects many common-size electric storage models to need heat pump technology to comply. It applies to newly manufactured units, so a working heater you own today does not have to be replaced. The rule can change, so check DOE's water heater page for the current status.
Tax credit: The federal 25C credit that covered up to $2,000 a year for heat pump water heaters does not apply to property placed in service after December 31, 2025, according to the IRS. Some states, utilities and local programs still offer rebates, and the DSIRE database lists incentives by state.
How this varies by region
| Where you live | What changes |
|---|---|
| Hard-water areas (much of the east-central and western U.S.) | Sediment builds faster, so flush the tank and check the anode rod more often |
| Cold climates | A heat pump water heater needs a spot that stays between 40 and 90 degrees Fahrenheit year-round with at least 1,000 cubic feet of air around it, so an unheated garage or basement may not work |
| Warm climates | DOE notes heat pump water heaters work more efficiently in a warm climate, and the unit cools the space it sits in |
| Everywhere | Permit and inspection rules are set locally, so call your building department |
Does insurance cover a failed water heater?
A standard homeowners policy typically covers sudden and accidental water damage to floors, walls and belongings, but excludes routine wear and tear, and the Insurance Information Institute notes it generally does not cover flood. Slow leaks that go on for weeks are often excluded. Read your policy, ask your agent, and keep a record of the heater's age and maintenance.
Track yours in Steadwell
Add your water heater to Steadwell with a photo of its rating plate. AI scan (Plus and Pro plans) reads the model and serial number, the warranty tracker keeps its coverage dates, and the home maintenance tracker schedules recurring tasks such as flushing the tank, inspecting the anode rod and testing the relief valve. Steadwell also tracks each item's age against an expected lifespan and flags it as it ages, so replacement is a plan and not an emergency.
Frequently asked questions
How do I find my water heater's manufacture date?
Find the rating plate on the side of the tank, read the serial number and decode the first few characters using your brand's format. If the code does not produce a believable date, enter the serial number on the manufacturer's website or call them.
How long does a tank water heater last?
Usually 8 to 12 years, and some last up to 15. Hard water and skipped maintenance shorten that, while an anode rod replaced on time can help.
Should I replace my water heater before it fails?
Past about 10 years, planning a replacement is usually smarter than waiting. A planned swap costs a few hundred to a few thousand dollars, and an unplanned failure can add water damage and rush pricing.
Do I need a permit to replace a water heater?
In most jurisdictions, yes, even for a like-for-like swap. A licensed plumber normally pulls the permit and schedules any inspection. Check with your local building department.
Is a heat pump or tankless water heater worth it?
Heat pump models are two to three times more efficient than standard electric resistance heaters, according to DOE, but they need the right location and cost more up front. Tankless units last longer and do not hold a tank of water, but they cost more to install and need descaling in hard-water areas. The answer depends on your hot water use, climate and budget.
How do I find the age of a Rheem, Ruud or Richmond water heater?
Read the serial number on the rating plate. The first four digits are the month and the year, so a serial starting 0719 was built in July 2019. InterNACHI's dating chart lists Ruud and Richmond with the same pattern as Rheem. See Rheem's guide to reading its serial numbers.
How do I find the age of an A. O. Smith water heater?
On an A. O. Smith serial number, the second character is a letter for the month (A is January, B is February, and so on) and the third and fourth characters are the year. A serial starting AB22 was built in February 2022, according to InterNACHI's water heater dating chart.
How do I find the age of a State water heater?
On a State water heater, the first character is a letter for the month (A is January, B is February, and so on) and the next two characters are the year. A serial starting C22 was built in March 2022, according to InterNACHI's dating chart.
How do I find the age of a Bradford White water heater?
The first two characters of a Bradford White serial number are letters: the first is the year and the second is the month. Month letters run from A (January) to M (December) and skip I. Year letters repeat every 20 years and skip some letters, so each letter fits two possible years: A is 2004 or 2024, and W is 2000 or 2020. A serial starting WC would be March 2000 or March 2020, and your home's records or the unit's condition usually show which. See Bradford White's age guide.
How do I read an American, U.S. Craftsmaster or Whirlpool water heater serial number?
InterNACHI's dating chart lists these brands with the same pattern: the first two digits are the year and the next two are the week of the year. A serial starting 2206 was built in the sixth week of 2022.
How do I find the age of a GE or Hotpoint water heater?
InterNACHI's chart lists GE and Hotpoint as trade names that follow Rheem's pattern: the first two digits are the month and the next two are the year. Check that the result is a believable date, and confirm with the manufacturer if it is not.
How do I read a Marathon, John Wood or GSW water heater serial number?
According to InterNACHI's chart, Marathon serial numbers start with the month and then the year. GSW brands such as John Wood do the reverse: the first four digits are the year and then the month. Treat either as an estimate and confirm with the manufacturer if the date does not look right.
How old is my Kenmore water heater?
InterNACHI's chart lists Kenmore but gives no decoding rule for it. Look for a manufacture date printed on the rating plate, or contact the manufacturer with the model and serial number. Our guide to finding an appliance serial number shows where the label sits.