How to Flush a Water Heater and Keep Your Hot Water Flowing

Got a water heater that’s taking forever to heat up or making weird noises? Chances are sediment has built up inside the tank. Flushing the heater removes that gunk, saves energy, and can add years to the unit’s life. The good news? You can do it yourself in under an hour with just a few tools.

Why You Should Flush Your Water Heater

Every time you use hot water, minerals from the supply line settle at the bottom of the tank. Over time they turn into a thick layer of sludge that acts like an insulator. That means the burner has to work harder, your electricity or gas bill goes up, and the heater’s lifespan shortens. You might also notice rumbling noises, rust-colored water, or a drop in water temperature.

Flushing gets rid of the sediment, restores efficient heating, and reduces the risk of premature tank failure. If you have hard water, aim for an annual flush; if your water is softer, every 2‑3 years is usually enough.

Step‑by‑Step Guide to Flushing a Water Heater

1. Turn off power or gas. For electric heaters, switch off the breaker at the consumer unit. For gas models, set the thermostat to “off" and turn the gas supply valve to the closed position.

2. Shut off the cold‑water inlet. Locate the valve on top of the tank and turn it clockwise until it stops. This stops fresh water from entering while you drain.

3. Connect a garden hose. Attach one end to the drain valve at the bottom of the tank and run the other end to a floor drain, bathtub, or outside area where hot water can safely flow.

4. Open the drain valve. Allow the water to flow out. It may sputter at first as air replaces the water. Let it run until the flow looks clear.

5. Flush the tank. Once the tank is empty, briefly open the cold‑water inlet valve while the drain valve stays open. This forces fresh water through the tank, stirring up any remaining sediment. You’ll see cloudy water at first; keep the water running until it’s clear again – usually a couple of minutes.

6. Close valves and refill. Shut the drain valve, remove the hose, and fully open the cold‑water inlet. Let the tank fill completely; you’ll hear the water pressure building.

7. Restore power or gas. Turn the breaker back on for electric models, or reopen the gas valve and set the thermostat to your desired temperature (around 120°F/49°C is efficient and safe).

8. Check for leaks. Look around the drain valve and inlet connections. A small drip can be fixed with a tighter nut or a bit of plumber’s tape.

That’s it – you’ve just given your water heater a fresh start. If you hear strange noises again after a few weeks, it might be time to check the anode rod, which protects the tank from corrosion.

Regular flushing is a low‑cost maintenance habit that pays off in lower energy bills and fewer emergency repairs. Keep a simple schedule in your home maintenance calendar and you’ll enjoy steady, hot showers for years to come.