Water Heater Age: How to Find It From the Serial Number

Knowing your water heater age tells you whether a strange noise is a quick fix or a warning sign, whether a repair is worth paying for, and how soon to start saving for a replacement. The age is printed on the tank, but usually hidden in a code in the serial number rather than written as a date. This free water heater age finder decodes Bradford White serial numbers on the spot, sends you to the official lookup for Rheem and A. O. Smith brands, and then shows how your water heater age compares with a typical lifespan.

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Table of Contents

How Old Is My Water Heater? Start With the Rating Plate

Every water heater has a rating plate, a metal or paper label on the side of the tank, usually near the top or beside the gas valve or thermostat cover. It lists the brand, the model number, the serial number, the capacity and the fuel type. Some newer labels also print a manufacture date outright, so check for that first.

If there is no printed date, the serial number holds the answer to “how old is my water heater.” Each manufacturer has its own code, which is why one brand’s chart won’t work on another. Write the serial number down exactly, including any letters, and you’re ready to look up your water heater age.

How the Water Heater Age Finder Works

Choose the brand printed on the label, and whether it is a tank or tankless model.
For Bradford White, type the serial number and click “Decode the serial.” The tool reads the year and month code and fills in the date for you.
For Rheem, Ruud and Richmond, it opens Rheem’s official age calculator. For A. O. Smith, State, American and Reliance, it opens A. O. Smith’s official serial number lookup. Enter the year you find there.
For other brands, it shows where to find a printed date and when to call the manufacturer.
Click “How old is it?” to see your water heater age, the typical lifespan for your type, where yours sits on that range, and what to do next.

We only decode serial numbers where the manufacturer publishes its own date code. Brands change their formats over time, and an outdated third-party chart can be off by years, so for the other brands we link straight to the manufacturer instead of guessing your water heater age.

Bradford White Water Heater Age: How to Read the Serial Number

Bradford White publishes its date code, which makes its water heater age easy to read. According to Bradford White, the first two characters of the serial number are the year and month of manufacture, and the rest is a sequential production number.

First letter, the year. The letters run on a 20-year cycle: A = 1984 or 2004, B = 1985 or 2005, and so on through Z = 2003 or 2023, then starting again with A for 2024. Bradford White skips I, O, Q, R, U and V for the year.
Second letter, the month. A = January through M = December, skipping I.
The digits that follow. Bradford White says the production number was seven digits long before December 2007 and eight digits after. That is how the tool tells a 1994 heater from a 2014 one with the same letter.

So a serial starting “LJ” followed by eight digits is a September 2014 water heater: L is 1994 or 2014, J is September, and eight digits rules out 1994. Bradford White also notes that some “OA” serials were built in January 1997 because of a computer error. If you want a second check, Bradford White’s My Water Heater page shows the manufacture date when you enter the serial number.

Rheem, Ruud and Richmond Water Heater Age

Rheem offers an official “How Old Is My Equipment” calculator on its website: choose water heater, enter the serial number, and it tells you the age. Ruud and Richmond are Rheem brands, so try the same calculator first, and call the number on the label if it doesn’t recognize the serial. Rheem’s serial formats have changed over the years, which is why the tool hands you to Rheem’s own lookup rather than decoding the water heater age itself.

A. O. Smith, State, American and Reliance Water Heater Age

A. O. Smith’s website has an official serial number lookup for warranty verification, and the same company makes the State, American and Reliance brands. Enter the serial number to see the warranty status. For the exact manufacture date, call the customer service number on the rating plate with the serial number ready; they can tell you the water heater age directly. A. O. Smith says most of its water heaters last 8 to 12 years, and that a heater more than 10 years old that is leaking or acting inconsistently is likely due for replacement.

Other Brands: GE, Whirlpool, Kenmore and More

Store brands and appliance brands such as GE, Whirlpool and Kenmore have been built by different manufacturers over the years, so there is no single code to read. Look for a printed date on the rating plate first. If there isn’t one, call the customer service number on the label. As a last resort, check the installation receipt, the permit sticker or a date the installer wrote on the tank. An install date is close enough to estimate the water heater age, since most heaters are installed within a year or so of being made.

Water Heater Serial Number Lookup: Tips That Save Time

Use a flashlight and your phone camera. Labels in basements and closets are hard to read. Take a photo and zoom in.
Copy every character. A water heater serial number lookup fails if a letter is read as a number. O and 0, and I and 1, are the usual mix-ups.
Tankless units usually have the label on the side or inside the front cover. Don’t open a cover that needs tools; ask your plumber at the next service visit.
Write the model and serial number down somewhere you’ll find them. You’ll need both for warranty claims, replacement quotes and parts.

Where to Find the Label on Each Type

Gas tank: on the side of the tank, usually just above the gas control valve near the bottom. Don’t remove the burner access cover to look.
Electric tank: on the side of the tank, often between the upper and lower element covers.
Heat pump (hybrid): on the side of the tank or on the upper unit near the controls.
Tankless: on the side of the cabinet or behind the front cover. Many tankless units also show model information on the control panel’s service menu, as described in the manual.

If the label has faded or peeled off, look on the original box or manual if you kept them, or ask the installer; contractors often keep records by address. Without any label, your water heater age is an estimate based on the install date.

Water Heater Age and Your Warranty

Water heater warranties run for a set number of years, printed in the manual and often on the label. Many manufacturers count from the manufacture date unless you can show the install date with a receipt or registration, which is one more reason to know your water heater age. Before paying for a repair, check whether the tank or the part is still covered; a failed thermostat, element or gas valve may be covered for parts even when labor isn’t. If the heater is past its warranty and inside its typical range, a big repair deserves a second look.

Checking Water Heater Age When You Buy a Home

Home inspectors usually note the water heater age in their report, because it is one of the most predictable near-term costs in a house. If the report says the heater is past its typical range, budget for a replacement in the first year or two, and consider asking for a credit at closing. Our guide to the costs of selling a house covers how repair credits work from the seller’s side. After you move in, write the water heater age into the lifespan tracker alongside the furnace and air conditioner so you can see which replacement comes first.

What Your Water Heater Age Means

Once you know your water heater age, compare it with a typical service life. Our home system lifespan tracker uses ranges from InterNACHI and Rheem: about 6 to 12 years for a tank water heater and about 10 to 20 years for a tankless one. Water quality, maintenance and how hard the heater works all move a particular unit up or down that range. The tool sorts your water heater age into four groups:

Well inside its expected life. Keep up with maintenance and it should have years left.
Approaching the range. Not urgent, but a good time to price a replacement and start setting money aside.
Inside the range. It could keep going or fail at any point. Weigh any repair carefully.
Past the range. It may still work, but plan the replacement now, before a leak forces the decision.

Signs That Matter More Than Water Heater Age

Water heater age is a guide, not a deadline. These signs matter at any age:

Water around the base of the tank. A leaking tank usually can’t be repaired. Check the fittings and the relief valve line first; if the tank itself is leaking, replacement is the fix.
Rusty or discolored hot water can mean corrosion inside the tank, especially in an older heater.
Rumbling or popping often means sediment build-up, which a flush may help.
Not enough hot water can be a failing element or burner, a thermostat setting, or a heater that is simply too small for the household now.

For a gas water heater, a smell of gas, scorch marks or a pilot that keeps going out are safety problems; leave the area and call the gas company or a licensed professional.

Repair or Replace? Let the Water Heater Age Decide the Close Calls

A cheap repair on a young heater is almost always worth it. An expensive repair on an old one usually isn’t. A common rule of thumb is that if a repair costs more than half the price of a new heater, or the heater is near the end of its range, replacing it is often the better value. Run your quote through our free repair or replace calculator with your water heater age, and it will show the verdict with the reasoning. To see what a new heater would cost, use the water heater replacement cost estimator.

How to Help an Older Water Heater Last

Maintenance can’t reverse water heater age, but it can help a heater reach the top of its range:

Drain sediment. The Department of Energy’s Energy Saver guide suggests draining about a quart of water from a tank every three months.
Test the relief valve the way the manual describes.
Keep the temperature around 120°F, which Energy Saver recommends for most households.
Ask about the anode rod at a service visit. It wears away to protect the tank, and replacing it on a heater that is still sound can extend its life.

Our free home maintenance calendar puts these on a schedule so they don’t slip.

A Worked Example

Say the label on a gas tank heater reads Bradford White, serial number LJ12345678. The tool reads L as 1994 or 2014, J as September, and the eight-digit production number as after December 2007, so the heater was made in September 2014. In October 2026 that water heater age is 12 years, at the very top of the 6 to 12 year range for a tank. The tool marks it “Past range” and suggests pricing a replacement now. If the same homeowner gets a $700 repair quote, the repair or replace calculator would flag it, because a repair that size on a heater this old is rarely the better value.

Planning for the Replacement

A new tank water heater typically costs somewhere between several hundred and a few thousand dollars installed, depending on the type, size and any venting or gas work, and tankless models cost more. Once you know your water heater age and its expected range, you know roughly how many months you have to save. The home repair fund calculator turns that into a monthly amount, so the replacement is planned rather than an emergency.

Frequently Asked Questions

How do I find my water heater age?

Find the rating plate on the tank and look for a printed manufacture date. If there isn’t one, decode the serial number: the tool above does this for Bradford White and links to the official lookups for Rheem and A. O. Smith brands.

How old is my water heater if the serial starts with two letters?

If it is a Bradford White, the first letter is the year and the second is the month. Other brands use different codes, so check the brand before you read the letters.

Is there a universal water heater serial number lookup?

No. Each manufacturer uses its own format, and some have changed formats over time. Use the manufacturer’s official lookup or call the number on the label.

What is a normal water heater age before replacement?

About 6 to 12 years for a tank model and about 10 to 20 years for tankless, based on InterNACHI and Rheem ranges. Many heaters are replaced inside those ranges after a leak or a costly repair.

Does the install date tell me the water heater age?

Closely enough for planning. Most heaters are installed within a year or so of being made, so the install date from a receipt or permit is a reasonable stand-in when you can’t read the serial number.

Should I replace a water heater just because of its age?

Not necessarily. Age tells you the odds, not the outcome. Many people replace a heater that is past its range before it fails, to avoid a leak and choose the replacement calmly, while others wait for signs like rust, leaks or rising repair bills. Either is reasonable if you have the money set aside.

Does the tool save my serial number?

Only in your own browser, so you can come back to it. Nothing is sent to Frugal Beans or any manufacturer. Use “Clear” to remove it.

The Bottom Line

Your water heater age is on the tank, and once you know it you can make better decisions about repairs, maintenance and saving for a replacement. Use the free finder above to decode or look it up, then compare it with a typical lifespan. For typical repair costs and a printable replacement ledger for every major system, get our free Homeowner Repair Cost Playbook, and see all of our free home repair tools.

Sources: Bradford White’s published serial number date code chart; Rheem’s How Old Is My Equipment calculator; A. O. Smith’s warranty verification lookup and replacement guidance; typical service lives from InterNACHI and Rheem; maintenance guidance from the U.S. Department of Energy’s Energy Saver guide. This tool provides general information, not professional advice.