How to Flush Your Hot Water Tank (And Why You Should)

Apr 29

Your hot water tank works hard behind the scenes to keep your showers warm, your dishes clean, and your laundry fresh. But like any hardworking appliance, it needs regular maintenance to perform efficiently—and one of the simplest yet most effective maintenance tasks is flushing the tank. In this guide, we’ll break down how to flush your hot water tank step-by-step and explain the key benefits of doing so.

Why Flush Your Hot Water Tank?

Over time, sediment—minerals, debris, and other particles—builds up in your water heater. This can lead to:

Reduced efficiency and higher energy bills
Less hot water availability
Noisy operation (rumbling or popping sounds)
Shortened lifespan of the unit
Potential clogs in pipes and valves

Flushing your hot water tank annually helps remove this sediment and keeps your system running smoothly.

What You'll Need:

Garden hose
Flathead screwdriver (for some valves)
Bucket or access to a nearby floor drain
Gloves (optional but recommended)

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

Step 1: Turn Off the Water Heater

For electric models, switch off the power at the circuit breaker.
For gas models, set the thermostat to "pilot" or turn off the gas supply entirely.

⚠️ Never flush a water heater while it's actively heating—this could be dangerous.

Step 2: Turn Off the Cold Water Supply

Locate the cold water inlet valve at the top of the tank and turn it off to stop additional water from entering the tank.

Step 3: Connect a Garden Hose to the Drain Valve

Attach a garden hose to the drain valve at the bottom of the tank. Run the other end to a floor drain, driveway, or large bucket (make sure it's in a place that can safely handle hot water).

Step 4: Open the Pressure Relief Valve

This is usually located near the top or side of the tank. Open it to allow air into the tank, helping water flow out more easily.

Be careful—hot water may be released.

Step 5: Drain the Tank

Open the drain valve (using a screwdriver if necessary) and let the tank empty completely. You’ll likely see cloudy or dirty water—this is the sediment you’re flushing out.

Step 6: Flush with Cold Water

Turn the cold water supply back on for a minute or two while the drain valve is still open. This will stir up and remove any remaining sediment from the bottom of the tank. Once the water runs clear, shut off the drain valve.

Step 7: Refill the Tank

Close the pressure relief valve.
Remove the hose from the drain valve and close it tightly.
Turn the cold water supply back on fully and let the tank refill.

Leave a hot water tap open in your house to release air from the system until water flows steadily.

Step 8: Restore Power or Gas

For electric heaters: Turn the circuit breaker back on.
For gas heaters: Turn the thermostat back to its normal setting or relight the pilot if needed.

The Benefits of Flushing Your Water Heater

Improved Efficiency: Less sediment means your unit heats faster and uses less energy.
More Hot Water: Flushing removes the buildup that takes up space inside your tank.
Extended Lifespan: Prevents corrosion and strain on internal components.
Quieter Operation: Eliminates the popping and banging caused by trapped sediment.
Fewer Repairs: Regular maintenance can prevent costly issues like clogged valves or leaking tanks.

How Often Should You Flush It?

For most households, once a year is enough. However, if you have hard water or notice signs of sediment (like noise or discolored water), consider doing it every 6 months.

Flushing your hot water tank is a simple DIY task that can pay off in energy savings and fewer headaches down the road. If you’re unsure about doing it yourself, a licensed plumber can perform the service quickly and safely.