Typical lifespan by type
- Gas tank water heater: about 8 to 12 years.
- Electric tank water heater: about 10 to 15 years, since there is no burner or flue to wear out.
- Tankless (on-demand) water heater: about 15 to 20 years, if it is descaled regularly.
These are averages, not guarantees. A well-maintained tank in a home with moderate water can outlast them, and a neglected one in a hard water area can fail well before.
What shortens a water heater's life
- Hard water. Minerals settle as sediment in a tank and as scale on tankless heat exchangers, making the heater work harder and corroding the tank. York Region reports its water is usually hard or very hard, while Toronto's Lake Ontario water is only moderately hard.
- No maintenance. A tank that is never flushed fills with sediment, and a sacrificial anode rod that is never checked eventually dissolves, leaving the tank itself to corrode.
- Heavy use. A tank feeding several bathrooms, a basement apartment or a large household cycles more often and wears faster.
- High temperature or pressure. Very hot settings and high water pressure put extra stress on the tank and valves.
- Poor installation. Undersized venting, a missing expansion tank where one is needed, or a tank that is too small for the house all shorten its life.
How to tell how old your water heater is
Look for the rating plate, a sticker on the side of the tank. Some show the manufacture date directly. Most encode it in the serial number, often as a letter for the month and digits for the year, or as the first four digits for the year and week. The manufacturer's website or a quick call to us can decode it.
If the heater is rented, the rental company can also tell you its age.
Signs your hot water tank is near the end
- Water pooling around the base, or rust on the bottom of the tank
- Rusty or discoloured hot water
- Rumbling, popping or banging as it heats, from sediment at the bottom
- Hot water running out much faster than it used to
- A pressure-relief valve that drips or discharges
- The tank is past about 10 years old and needs a major repair
Water leaking from the tank itself cannot be repaired. Turn off the cold water supply and the gas or power to the heater, and call a plumber. Our guide to the signs your water heater is failing covers each one in more detail.
Repair or replace?
A failed thermostat, heating element, igniter, gas valve or relief valve is usually worth repairing, especially on a younger heater. A tank that leaks, is badly corroded, or is past about 10 years and needs a major part is usually better replaced.
Replacing is also a chance to rethink the size and type. Households that keep running out of hot water often need a larger tank or a tankless unit. Our comparison of tankless and tank water heaters walks through the trade-offs.
If your hot water tank is rented
Many Ontario homes rent their water heater rather than own it. With a rental, repairs and replacement of the rented unit are usually the rental company's job, so check your agreement before paying for work on it yourself.
An old rented tank is also a good moment to decide whether to keep renting or switch to a heater you own. Rental agreements often set out how the old tank is returned and whether there is a buyout or removal charge, so read those terms before you replace it.
How to make your water heater last longer
- Flush the tank once a year to drain the sediment, more often with hard water.
- Have the anode rod checked every few years and replaced before it is used up.
- Test the temperature and pressure relief valve once a year.
- Descale tankless units on the manufacturer's schedule.
- Keep the area around the heater clear, and make sure venting is not blocked.
- Keep the tank hot enough to control bacteria, and use mixing or anti-scald valves so water at the tap is not too hot.
Water heater help near you
We repair, replace and install tank and tankless water heaters, with a flat quote before any work starts. See our local pages for Toronto, Markham and Richmond Hill, or our water heater services across York Region.