How old is your water heater? Reading the label and serial number

Start with the rating label

Every tank and tankless heater has a rating label, usually on the side of the tank or the front of the cabinet. It lists the model, capacity, fuel type and serial number. Some labels also print a manufacture date directly, which makes the job easy.

If the label is hard to read, take a photo with your phone's flash on and zoom in. Dust and garage grime often hide the numbers.

Decoding the serial number

When no date is printed, the serial number usually contains it. Most manufacturers put the year and month or week in the first few characters, either as numbers or as a letter code. The pattern differs by brand, and brands have changed their formats over the years.

The surest way is to search the brand name with the words serial number date, or call the manufacturer's support line with the serial in hand. We can also read it for you on any visit.

What the age tells you

Tank water heaters in the Sacramento area commonly last 8 to 12 years. Hard water, skipped flushing and high water pressure shorten that. Tankless units commonly last 15 to 20 years with yearly descaling.

A tank past 10 years is not guaranteed to fail, but the odds rise every year, and tanks rarely give much warning before they leak.

Repair or replace

On a younger heater, a failed thermocouple, igniter, element or thermostat is worth repairing. On an older tank, put the money toward a planned replacement, especially if you see rust at the fittings or water around the base.

Planning ahead also gives you time to consider tankless or a heat pump unit instead of an emergency like-for-like swap.

Where the age shows up on the bill

An older tank loses efficiency as sediment builds on the bottom and insulation ages. Gas heaters burn longer to heat the same water, and electric elements run longer. The change is gradual, so it rarely gets noticed until the heater is replaced and the bill drops.

If your heater is past ten years and the household has not changed, a rising gas or electric bill is one more sign the tank is near the end.

Signs to watch regardless of age

Rust-colored hot water, popping or rumbling sounds, water pooling at the base, a relief valve that drips and hot water that runs out faster than it used to all point to a heater that needs attention.

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