How Long Does It Take To Drain A Water Heater?

Are you looking for draining water heater but need to know how long it takes? You’ve landed in the right space. In fact, we're going to explain why it's necessary. We'll also demonstrate how to properly drain your water heater tank.

Table of Contents

1. Why Should I Drain My Water Heater?

2. How Long Does It Take to Drain a Water Heater?

3. How Often Should You Drain Your Water Heater?

4. How Much Does It Cost to Drain a Water Heater?

5. Signs Your Water Heater Needs Draining

6. What Tools Do You Need Before You Start?

7. Step-by-Step: How to Drain a Water Heater Tank

8. Safety Tips Before and During Draining

9. When I’m Done, How Do I Refill the Tank?

10. Common Mistakes to Avoid

11. Final Thoughts

12. Related Resources

13. Call DreamDen Experts

Why Should I Drain My Water Heater?

Over time, your water heater collects sediment and mineral deposits—mainly calcium and magnesium—at the bottom of the tank. This buildup forces your heater to work harder, which increases energy use and can shorten its lifespan.

Draining your water heater once or twice a year flushes out these deposits, helping you:

• Improve heating efficiency

• Reduce noise from bubbling or popping sounds

• Extend your heater’s life

• Save money on utility bills

According to the U.S. Department of Energy, regular maintenance like flushing can improve efficiency by up to 25% for older heaters.

How Long Does It Take to Drain a Water Heater?

The whole process typically takes 30 to 45 minutes for most residential tanks. Here’s the time breakdown:

• Turning off the power or gas: 5 minutes

• Cooling down the water: 20 minutes

• Draining and flushing: 10–15 minutes

• Refilling and reheating: another 20–30 minutes

Tip: If your heater hasn’t been drained in years, it may take longer because the sediment layer will be thicker.

How Often Should You Drain Your Water Heater?

Most experts recommend draining your water heater every 6 to 12 months.If you live in an area with hard water, aim for every 6 months.If you have a water softener or low-sediment supply, once a year should do.

Pro Tip: Install a water softener to reduce mineral buildup—it makes future flushes faster and easier.

How Much Does It Cost to Drain a Water Heater?

If you DIY the job, it’s practically free (just your time and some water).If you hire a professional plumber, you can expect to pay around:

Service Type	Average Cost (USD)	Notes
DIY	$0–$5	Just need a hose & bucket
Professional Drain & Flush	$80–$200	Includes inspection
Tank Cleaning + Maintenance	$150–$300	Ideal for older tanks
Tankless Water Heater Flush	$150–$450	Requires vinegar or descaling kit

(Sources: HomeAdvisor, Angi, BobVila.com)

Signs Your Water Heater Needs Draining

If you’re not sure when to drain, look for these telltale signs:

• Strange popping or rumbling sounds (caused by trapped steam under sediment)

• Cloudy or rusty water from the tap

• Low hot water pressure

• Water taking longer to heat up

• Increased energy bills

If two or more of these sound familiar, your heater probably needs a good flush.

Step-by-Step: How to Drain a Water Heater Tank

Let’s walk through the process — simple, safe, and stress-free.

Step 1: Turn Off Power or Gas

• For electric heaters, flip the breaker switch to OFF.

• For gas heaters, turn the control knob to the PILOT position.

Step 2: Turn Off Water Supply

Locate the cold-water valve at the top of the heater and close it.

Step 3: Wait for the Water to Cool

Hot water can cause burns, so give it 20–30 minutes to cool.

Step 4: Attach Hose to Drain Valve

Connect your garden hose to the spigot at the bottom of the tank. Run the other end to a floor drain, bucket, or outside area.

Step 5: Open the Pressure Relief Valve

This lets air into the tank so it can drain smoothly.

Step 6: Open the Drain Valve

Turn it counterclockwise to let water flow out.If water doesn’t flow freely, sediment may be blocking it.Tap the valve gently or use a small screwdriver to clear it.

Step 7: Flush the Tank

Once the tank is empty, briefly turn the cold-water supply back on to stir up any leftover sediment, then let it drain again.

Step 8: Close Valves and Disconnect Hose

Close the drain valve tightly, then remove the hose.Close the pressure relief valve too.

Safety Tips Before and During Draining

• Always let the water cool before opening valves.

• Wear gloves and eye protection.

• Never use chemical cleaners inside your tank.

• If your heater is over 10 years old, consult a plumber before draining—it might need inspection first.

When I’m Done, How Do I Refill the Tank?

1. Close the drain valve.

2. Turn the cold-water supply back on.

3. Open a hot-water faucet in your home to let air escape.

4. When water flows smoothly, you know the tank is full.

5. Turn power or gas back on.

You’ll have hot water again in 30–45 minutes.

Draining your water heater isn’t as complicated as it sounds—it’s a simple task that can save energy, prevent costly repairs, and extend your tank’s life. Doing it once or twice a year keeps your water hot, clear, and reliable. If you’re nervous about doing it yourself, or if your tank is old or rusty, calling a professional can ensure everything runs safely and smoothly.

Related Resources

• Energy.gov – Water Heating Tips

• Home Depot – How to Drain a Water Heater

• Bob Vila – Water Heater Maintenance Guide

• Angi – Water Heater Flush Cost