How to Drain a Water Heater

Draining a water heater is an important maintenance task that helps extend the life of your appliance. Over time, sediment can build up at the bottom of the tank, reducing efficiency and potentially causing corrosion. Draining flushes out this sediment to keep your water heater running smoothly.

Draining your water heater is usually a straightforward DIY project that you can tackle in an afternoon. However, there are a few important safety considerations to keep in mind. Properly shutting off power and water supply lines is crucial to prevent leaks or electric shocks. You’ll also need to take precautions against burning yourself on the hot water.

With a few simple tools and proper precautions, you can drain your water heater safely. We’ll walk through the complete process step-by-step, from shutting off water and power to flushing the tank. Read on to learn how to drain a water heater like a pro!

Gather Necessary Supplies and Tools

Before starting the draining process, you’ll want to gather everything you need. Having the right gear close at hand will make the job much smoother. Here are the recommended supplies:

  • Garden hose – Used to drain water from the tank exterior. Make sure it’s long enough to reach from your water heater to a safe drainage area.
  • Adjustable wrench – For loosening fittings and valves. Having one that’s 6 or 8 inches works best.
  • Bucket – Collects initial hot water drainage. A 2-3 gallon bucket is ideal.
  • Flashlight – Helps you see inside dark water heater closets.
  • Gloves – Protect hands from hot pipes and valve handles. Heat-resistant rubber gloves are best.
  • Safety glasses – Shield eyes from sediment during tank flushing.

You’ll also need any specific tools required to operate shutoff valves for your water and power supply lines. These often include flathead and Phillips screwdrivers. Gather everything before starting so you’re fully prepared.

Shut Off Power Supply

The first step is disconnecting electrical power to the water heater so there is no risk of shock. Locate the circuit breaker or fuse powering the appliance and switch it off.

If you have a gas water heater, turn the control knob on the gas control valve to “pilot” or “off.” This stops gas flow to the pilot light and burner.

Double check that all power is disconnected by trying to run hot water. If the heater activates, keep looking for any switches or breakers that need shutting off.

With the power supply completely disabled, you can move on to the next steps safely.

Shut Off Water Supply Lines

Before draining the tank, you need to stop water from refilling it by shutting off the supply lines. There are typically two:

Cold water supply – Locate the cold water shutoff valve feeding water to the heater and turn it clockwise to the “off” position.

Hot water outlet – Find the hot water line exiting the top of the tank and close its shutoff valve too.

The valves are usually near the top and bottom of the water heater. Some types may require a flathead screwdriver to switch off. If you have difficulty locating or closing them, trace the pipes back to the main shutoffs and turn them off there.

Shutting off both lines prevents pressure buildup that could cause leaks while draining. Leave the valves in the closed position until the project is complete.

Connect Drain Hose

Now that water and power are disabled, you can set up the drain hose. Most residential water heaters have a spigot or valve at the bottom of the tank for draining.

Start by placing the bucket beneath the drain valve to catch the initial hot water discharge. Wearing heat-proof gloves, open the valve slowly. Hot water will begin flowing out – let it spill into the bucket.

Once the flow reduces to a trickle, you can attach your garden hose. Make sure it’s long enough to reach a suitable drainage area like a floor drain, laundry sink, or outdoors.

Tighten the hose firmly over the drain valve outlet using pliers or an adjustable wrench. Place the end of the hose in the drain receptacle before resuming water flow.

Flush the Tank

With the hose attached, you’re ready to flush out the water heater. This step removes any built-up sediment from the bottom of the tank.

Reopen the drain valve completely. The remaining water will now flow out through the hose. Let it drain until the tank is empty.

You may need to lift the hose occasionally to allow any remaining water pockets to empty. Draining can take 10-30 minutes depending on tank size and sediment levels.

While the tank drains, keep an eye out for unusual sediment color or texture. A small amount of mineral scale is normal but excessive debris could indicate corrosion issues.

Once water stops flowing, close the drain valve. Remove the garden hose and replace the outlet cap. Your tank is now empty and ready for inspection.

Inspect Interior and Flush Again if Needed

Before refilling, take the opportunity to check the empty tank interior with a flashlight. Look for any signs of rust, scale buildup, or damage.

If the walls appear overly corroded or coated with thick mineral deposits, you may need to flush again. Just reopen the drain, reattach the hose, and empty the tank fully one more time.

Double flushing helps remove all loose sediment for a deeper clean. If corrosion damage seems severe, consider having a professional inspect and service the water heater.

Refill the Tank

After inspecting and double checking that the drain valve is closed, you can refill the water heater:

  1. Remove the hose from the drain outlet and replace the cap.
  2. Open the hot water outlet valve first.
  3. Slowly open the cold water inlet valve next.
  4. Let the tank fill completely, monitoring for any leaks.
  5. Once full, open a hot water faucet to purge any air from the lines.
  6. Let water run until it flows smoothly, then close the faucet.

Your water heater is now refilled. Double check that all valves are fully open and no leaks are present before restoring power.

Restore Power

The final step is re-enabling electrical power to the appliance:

  1. For electric heaters, flip the circuit breaker back on.
  2. For gas models, turn the gas control valve back to “On” and relight the pilot if needed.
  3. Check that the temperature settings are still correct. Adjust if needed.

Monitor the water heater for several hours to ensure proper function. If any issues occur, shut off power immediately and call for service.

And that covers the complete process for draining a residential water heater! With annual draining, you can minimize sediment buildup and keep your heater running efficiently for years.

FAQs About Draining a Water Heater

Draining your water heater may seem intimidating at first, but is usually a quick and straightforward DIY project. Here are answers to some frequently asked questions:

How often should I drain my water heater?

Most manufacturers recommend draining and flushing your water heater tank once per year. This prevents too much sediment buildup that can lead to corrosion. Draining frequency depends on water quality – if you have hard water, draining every 6 months may be best.

How do I know when my water heater needs draining?

Signs it’s time to drain your water heater include reduced hot water pressure or volume, rumbling or popping noises, or leaks from the tank. Excessive corrosion or loose sediment in the flushed water also indicates you should drain more frequently.

What are the consequences of not draining a water heater?

Sediment buildup reduces heating efficiency since it insulates the tank bottom. It can also lead to corrosion and eventual water heater failure if left unattended. Draining flushes out sediment to avoid these issues.

Can I drain a gas water heater myself?

Yes, you can drain a gas water heater if you shut off the gas supply and use proper safety precautions. The draining process is essentially the same as electric models. Just be very careful working around a gas appliance.

How should I dispose of flushed water heater sediment?

In most cases, flushed sediment can be poured down a laundry or floor drain as long as it’s a small amount. If excessive debris comes out, contain it in buckets and check local hazardous waste disposal guidelines. Scale buildup may contain contaminants.

What should I do if my water heater won’t drain?

If no water comes out the drain valve, sediment has likely blocked it. Try closing and reopening the valve several times quickly to dislodge any debris. If that fails, the drain tube may need to be disconnected and cleared of obstructions.

Can I drain my tankless water heater too?

Tankless heaters need flushing on a regular basis to prevent scale buildup in the heating coils. This involves isolating sections and flushing with de-scaling solution. Follow your manufacturer’s draining procedures.

Regular water heater draining and flushing extends the life of your appliance by preventing sediment buildup. With some simple tools and safety precautions, it’s usually a quick DIY undertaking. Just be sure to take the proper steps outlined above. Drain your tank annually for optimal performance.


Draining a water heater is an essential maintenance task that helps prevent sediment accumulation and corrosion. While it may seem daunting, this guide has provided you a step-by-step walkthrough of the complete process.

The key steps include shutting off electrical power and water supply lines, connecting a hose to the drain valve, flushing the tank, inspecting for damage, and refilling once complete. Taking appropriate safety precautions like wearing gloves and glasses protects you throughout the process.

With annual draining, you can maximize your water heater’s life expectancy. The small time investment helps maintain heating efficiency and prevent costly repairs down the road. Just be sure to inspect the flushed sediment and interior for any signs of serious corrosion issues.

We hope this guide has made the process of draining a water heater clear and straightforward for you. Just gather the necessary tools, take it slow, and maintain vigilance against leaks or other hazards. Regular tank flushing prevents sediment buildup and keeps your appliance running smoothly for years to come.