A tank water heater is the appliance most people never think about until the shower goes cold. It needs very little: a flush about once a year and a couple of quick checks. Done regularly, that helps it run efficiently and last longer.
The intervals below are general guidance. Your heater's manual has the specifics for your model. If you're not comfortable working around gas, electricity, or very hot water, a plumber can do all of this in one visit.
The schedule
| Job | How often | Why it matters |
|---|---|---|
| Flush the tank | Yearly, or every 6 months with hard water | Clears the sediment that settles at the bottom and makes the heater work harder. |
| Test the temperature and pressure relief valve | Yearly | This safety valve releases pressure if the tank overheats. It should let water out when lifted and stop when released. |
| Check the anode rod | Every 2 to 3 years | The rod corrodes so the tank doesn't. Replace it when it's heavily eaten away. |
| Check the temperature setting | Once, then after any service | 120°F (49°C) is the usual recommendation. It's hot enough for most homes and lowers scald risk. |
| Look for leaks and rust | Every few months | Check the base, the fittings on top, and the drain valve. |
| Descale a tankless heater | Yearly, more often with hard water | Mineral scale builds up in the heat exchanger. Clean the inlet filter at the same time. |
How a flush works
This is an overview so you know what's involved, not a substitute for your heater's manual.
- Turn off the power at the breaker for an electric heater, or set a gas heater to pilot.
- Close the cold water supply valve at the top of the tank.
- Attach a garden hose to the drain valve and run it to a floor drain or outside.
- Open a hot tap somewhere in the house so air can get in, then open the drain valve.
- Let it drain until the water runs clear. Briefly opening the cold supply stirs up the last of the sediment.
- Close the drain valve, refill the tank completely, and only then turn the power or gas back on. An electric element that's switched on in an empty tank burns out.
Signs it's wearing out
- Rumbling or popping while it heats, which is water boiling under a layer of sediment.
- Rusty or cloudy hot water.
- Water pooling around the base of the tank.
- Hot water that runs out faster than it used to.
- Age. Most tank heaters last somewhere around 8 to 12 years.
Write down the install date
Knowing how old the heater is tells you whether a repair is worth it. The install date is often on a sticker on the tank, or coded into the serial number. Note it down along with the model number, so it's there when you need a part or a quote.
Common questions
How often should you flush a water heater?
About once a year for most homes. With hard water, every six months is better, because sediment builds up faster.
What temperature should a water heater be set to?
120°F (49°C) is the usual recommendation. It's hot enough for most households, lowers the risk of scalding, and uses less energy than a higher setting.
How long does a water heater last?
Most tank water heaters last around 8 to 12 years. Regular flushing and replacing the anode rod when it's worn can help it reach the longer end of that range.