How Often Should You Flush Your Water Heater? (And How to Do It)

Short answer: flush your water heater once a year — or every 6 months if you have hard water. It's one of the cheapest, highest-payoff maintenance tasks a homeowner can do, and almost nobody does it. The result? Water heaters that should last 12 years quietly fail at 7 or 8.

Here's why flushing matters, how to do it yourself in under an hour, and how to tell if you've already waited too long.

Why You Need to Flush a Water Heater

Every time your water heater runs, minerals in the water — calcium and magnesium — settle to the bottom of the tank as sediment. Over time that layer builds up and causes real problems:

• Wasted energy. Sediment insulates the water from the burner, so your heater works harder and your energy bill climbs.
• Less hot water. Sediment takes up space, so your "50-gallon" tank effectively holds less.
• Strange noises. That popping or rumbling sound is water trying to bubble up through the sediment layer.
• Early failure. Trapped heat stresses the tank and can crack the lining — turning a $50 task into an $800–1,500 replacement.

How Often Should You Flush It?

• Standard tank, normal water: once a year.
• Hard water (most of the US): every 6 months.
• Tankless water heater: descale once a year (more often with hard water).

Not sure if you have hard water? White crust on faucets and spotty dishes are the giveaways. When in doubt, flush twice a year — you can't really overdo it.

How to Flush a Water Heater (Step by Step)

This takes 30–60 minutes and just a garden hose. If anything feels unsafe — especially with gas — call a pro.

1. Turn off the power or gas. Electric: flip the breaker. Gas: set the valve to "pilot."
2. Shut off the cold water supply to the tank.
3. Let it cool for an hour or two so you don't scald yourself.
4. Connect a garden hose to the drain valve at the bottom and run it to a drain or outside.
5. Open a hot-water faucet somewhere in the house to let air in.
6. Open the drain valve and let the tank empty. Expect cloudy, gritty water.
7. Briefly turn the cold supply back on in bursts to stir up and flush remaining sediment until the water runs clear.
8. Close the drain valve, remove the hose, refill the tank (faucet will sputter, then run steady), then restore power/gas.

Cost: Essentially free. Pro alternative: $80–150 if you'd rather not.

Signs You've Waited Too Long

• Rumbling or popping sounds when it heats
• Rusty or cloudy hot water
• Running out of hot water faster than you used to
• Water pooling around the base (this one means call a plumber now)

If the tank is already 10+ years old and never been flushed, flushing can sometimes reveal a leak rather than cause one — so know where your shutoff is, and budget for a replacement if it's near end of life.

Don't Try to Remember This Yourself

A once-a-year task is exactly the kind of thing that's easy to forget — until your water heater fails on a Sunday. Upkeepify tracks your water heater's age and reminds you to flush it on schedule, so you get the full life out of it.

Start for free — no credit card required.

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