How to Flush Your Hot Water Tank (And Why It’s Essential)

Your hot water tank works behind the scenes every day — heating water for showers, dishes, laundry, and more. But like any appliance, it needs occasional maintenance to stay efficient. One of the easiest and most effective tasks you can perform is flushing the tank to remove sediment buildup.

Here’s why it’s important, and how to do it safely.

Why Flush Your Hot Water Tank?

Over time, minerals and debris settle at the bottom of the tank, causing:

• reduced heating efficiency

• higher energy bills

• rumbling or popping noises

• less available hot water

• stress on internal components

• increased risk of leaks or clogs

Flushing the tank once a year prevents sediment from accumulating and keeps your system running properly.

What You’ll Need

• garden hose

• flathead screwdriver (for some drain valves)

• bucket or access to a floor drain

• gloves (optional)

Step-by-Step: How to Flush Your Hot Water Tank

Step 1: Turn Off the Water Heater

• Electric models: Switch off the breaker.

• Gas models: Set the thermostat to Pilot or turn off the gas supply.

⚠️ Never flush a tank while it’s actively heating.

Step 2: Shut Off the Cold Water Supply

Turn off the cold-water valve on top of the tank to stop water from refilling during the flush.

Step 3: Connect a Hose to the Drain Valve

Attach a garden hose to the drain valve at the bottom of the tank and run the hose to a drain, driveway, or large bucket.

Step 4: Open the Pressure Relief Valve

Opening the T&P (temperature and pressure) valve lets air into the tank, helping water drain more easily.

Be careful — water may be hot.

Step 5: Drain the Tank

Open the drain valve and let the tank empty.
Cloudy or rusty water is normal — that’s the sediment being flushed out.

Step 6: Flush With Cold Water

Turn the cold water supply back on briefly while the drain valve is still open.
This helps stir and remove any remaining sediment.

Once the water runs clear, close the drain valve.

Step 7: Refill the Tank

• Close the pressure relief valve.

• Remove the hose and tighten the drain valve.

• Turn the cold water supply fully on.

Leave a hot water tap open inside the house until water runs smoothly to purge trapped air.

Step 8: Restore Power or Gas

• Electric heaters: Turn the breaker back on.

• Gas heaters: Return the thermostat to normal or relight the pilot.

Benefits of Flushing Your Water Heater

• Improved efficiency — heats faster and uses less energy

• More hot water — removes sediment taking up tank space

• Longer lifespan — prevents corrosion and overheating

• Quieter operation — eliminates rumbling and popping

• Fewer repairs — reduces strain on valves and components

How Often Should You Flush It?

Most households should flush their water heater once per year.
If you have hard water or notice noise/discolored water, flush every 6 months.

Final Recommendation

Flushing your hot water tank is a simple, worthwhile DIY task that can prevent major issues down the road. But if you’re uncomfortable doing it yourself, a licensed HVAC or plumbing technician can handle the job quickly and safely.