Most water heaters show their manufacture date coded in the serial number on the rating plate. Many brands use a letter for the month and two digits for the year, or the first four digits as year and week. Once you know the age, you can plan: tanks commonly last about ten to fifteen years, and tankless units often fifteen to twenty.
Finding the rating plate
The rating plate is a sticker on the side of the tank, usually near the gas control or upper element cover. It lists brand, model, serial number, capacity, and fuel.
Decoding the serial
Codes vary by brand. Common patterns include:
- Year then week: the first four digits, such as 1815, mean the 15th week of 2018.
- Letter for month, digits for year: such as "A" for January.
- Month and year digits: such as 0619 for June 2019.
The manufacturer's website or customer service can confirm.
Water heater acting up? Talk it through by phone.
Call 000 000 0000What age means
- Under eight years: most repairs make sense.
- Eight to twelve years: weigh repairs against replacement.
- Over twelve years: plan for replacement, especially with leaks or major part failures.
Signs of wear
Rusty hot water, rumbling, leaks at the base, and slower recovery are common signs of an aging tank.
Planning
Replacing before failure avoids emergency damage. See water heater replacement in Chicago. If the heater is young, see water heater repair in Chicago.
Efficient replacement
When it is time, ENERGY STAR's heat pump water heater page lists efficient models.
Local note
Many bungalows near Abraham Lincoln Park and across the city still have tanks installed a decade or more ago.
Common brand patterns
Manufacturers change their coding over the years, so these are examples, not rules. Some brands start the serial with four digits representing the year and the week of manufacture. Others start with a letter for the month (A for January, B for February, and so on) followed by two digits for the year. Others use a two-digit month and two-digit year. A few use longer codes that need the manufacturer's lookup. If the plate is faded, a phone photo with the flash on often makes it readable. If you cannot decode it, the manufacturer's customer service line can usually tell you the date from the full serial.
Age is not everything
A ten-year-old tank that was flushed yearly, had its anode replaced, and runs at normal pressure may outlast a six-year-old tank that was neglected. Look at the condition as well as the age: rust at the fittings, water at the base, scorch marks at the draft hood, and noises all say more than the date alone.
Tankless units
Tankless units also have a manufacture date in the serial. They often last fifteen to twenty years with regular descaling. Heat exchanger condition is the main factor.
Heat pump water heaters
Heat pump tanks have both a tank and a compressor. The tank wears like any tank. The compressor and fan have their own life. Keep the filter clean and the condensate drain clear.
Recording the age
Once you know the age, write the manufacture year and install date on a tag on the heater. It saves the next person time.
Planning a replacement budget
If your heater is approaching twelve years, start planning. Get a sense of whether you want the same type or something different, check whether your chimney and gas line support the choice, and ask about permits. Replacing on your schedule usually costs less than replacing in an emergency.
Selling a home
Home inspectors note the water heater's age. An old heater often becomes a negotiation item. A recent replacement with records can be a selling point.
Warranty
The warranty on a tank usually runs from the manufacture or install date, often six to twelve years. Knowing the age tells you whether a failed part might still be covered. Keep the receipt with the heater's records.
Related guides
See anode rods and flushing.