The essentials
- Draining a few pails of water from the tank every month, starting when the unit is new, keeps lime and sediment from settling at the bottom.
- The temperature-pressure relief valve opens at 210 degrees F or 150 PSI and is the most important safety device on the heater.
- An annual flush removes sediment that raises energy bills, cuts hot water capacity and strains the tank.
- Rusty water, rumbling noises, fluctuating temperatures or a relief valve that will not stop flowing all call for a plumber.
- Tankless units avoid most tank sediment problems, which makes them worth considering in hard water regions.
Water heaters fail quietly. Because a tank holds roughly 50 to 100 gallons, a leak that starts while nobody is home can soak more than a floor. The habits below take minutes each, spaced across the calendar, and they keep sediment down while catching small problems while they are still cheap to fix.
Every Month: Quick Visual Checks and a Pail Drain
Start with what you can see and hear. Look for puddles around the base, rust on fittings and drips from the discharge pipe near the relief valve. Listen when the burner fires: a gurgling sound points to sediment buildup that can damage the tank. While you are there, confirm that gasoline, paint and other flammables are stored well away from the unit.
Then do the drain that matters most. CenterPoint Energy advises draining several pails of water from the drain valve near the tank’s bottom every month, starting when the heater is new. This keeps lime deposits and sediment from settling where they are hardest to remove. The water will be hot, so point the pail away from your feet and hands. On an older tank that was never drained regularly, lime deposits may already be present, and the drain valve may not close completely afterward, leaving a constant drip.
Every Six Months: Test the Temperature-Pressure Relief Valve
The temperature-pressure relief valve, or TPR valve, is the heater’s main safety device. It opens automatically if the water reaches 210 degrees F or the pressure exceeds 150 PSI, venting hot water through the discharge pipe instead of letting the tank rupture. Building codes require every water heater to have one, and the Department of Energy recommends checking it annually.
To test it, lift the valve’s brass stem up and down several times. Hot water should gurgle out of the drainpipe. If nothing comes out, or only a trickle, have a plumber replace the valve. If water keeps flowing after the test, cycle the valve a few more times to free any debris. Manufacturers also call for a licensed plumber to remove and inspect the valve every two to four years, and a missing service label means it is due.
Safety first
An older TPR valve may not reseat after a manual test and can start dripping, which means a service call to replace it, so some plumbers recommend leaving an aging valve alone. Only test with a properly installed drain line that directs hot water to a safe disposal point.
Every Year: Flush the Tank and Check the Temperature
Once a year, do a fuller flush. For an electric unit, shut off the power at the panel; for gas, turn the gas supply to pilot. Attach a garden hose to the drain valve at the bottom of the tank, drain the tank, then close the valve and restore power. Sediment that escapes the monthly pail drain settles out this way, and a clean tank heats faster and costs less to run.
While you are at it, test the water temperature. The Consumer Product Safety Commission recommends 120 to 125 degrees F to avoid most scald injuries, and it lists children and the elderly as particularly vulnerable. Let hot water run from a bathroom faucet for one to three minutes, check it with a reliable thermometer, then repeat at the kitchen sink and other bathrooms. Turn the thermostat to the lowest setting comfortable for your household. Today’s dishwashers carry booster heaters, so 120 degrees F is sufficient and safe for most homes.
Every Year and Beyond: Professional Help and Planning Ahead
Sediment prevention is easier than removal. Schedule annual maintenance with a plumbing professional to address sediment cleaning and anything you cannot safely check yourself. If your region has especially hard water, ask about a water softener or a sediment trap that captures minerals before they reach the tank. Those two additions, plus the monthly pail drain, cover most of what shortens a tank’s life. For other ways to trim running costs, see 7 Ways to Lower Your Water Heating Bill.
Find the manufacture date on the rating plate and keep it with your maintenance notes. As a tank ages, the warning signs of sediment tend to return even with regular flushing: popping noises, reduced hot water supply and higher bills. That is the point to start researching a replacement rather than shopping in an emergency. In hard water regions, a tankless unit is worth considering because it largely avoids the tank sediment problem; a tankless model follows the manufacturer’s descaling and inspection schedule rather than the storage tank timeline here. A plumber can assess your unit and discuss options that fit your home.
Warning Signs That Mean Call a Plumber Now
Some symptoms should not wait for the next scheduled check. Call a plumber if you notice any of the following:
- Rusty, brown or discolored hot water, which can mean sediment has corroded tank components
- Popping or rumbling sounds that persist after a flush
- Fluctuating water temperature from uneven heating
- A TPR valve that flows continuously or not at all after testing
- A pilot light that will not relight following the manufacturer’s instructions
- A drain valve that will not close completely and drips constantly, common on older tanks that were never drained
- Water pooling around the base of the tank
Related Guides
- 7 Ways to Lower Your Water Heating Bill: settings, fixtures and habits that cut the cost of every gallon heated.
- HVAC Air Filters: Sizes, MERV Ratings and When to Change Them: pair filter changes with the monthly water heater check so the reminders happen together.
- A Fall Home Maintenance Checklist: where the annual flush and temperature check fit into your seasonal routine.
Common questions
How often should I drain my water heater tank?
CenterPoint Energy recommends draining several pails of water from the drain valve every month, starting when the heater is new, to keep lime deposits and sediment from building up. A fuller flush once a year clears out what the quick drains leave behind.
What temperature should my water heater be set to?
The Consumer Product Safety Commission recommends 120 to 125 degrees F to avoid most scald injuries, and 120 degrees is sufficient for most households. Modern dishwashers have booster heaters for the hotter water they need.
Should I test the temperature-pressure relief valve myself?
Manufacturers call for a homeowner test once a year, but some plumbers advise leaving the valve alone because an older valve may not reseat and will drip afterward. If you test it, make sure a drain line is connected and be prepared to have a plumber replace it.
How does hard water affect a water heater?
Hard water carries calcium and magnesium that settle at the bottom of the tank as it heats, forming a sediment layer that forces the heater to work harder. A water softener, sediment traps or a tankless unit can reduce the problem in hard water regions.
This guide is general information, not professional advice. Follow the manufacturer’s instructions and your local building codes, and hire a licensed professional for electrical, gas, structural or roofing work.