How to Drain Your Water Heater

Water heaters are simple devices with a fatal flaw: sediment. Minerals in your water settle to the bottom of the tank and accumulate over time. That layer of sediment insulates the water from the heat source, making the heater less efficient. It also causes rumbling noises, shortens the tank’s life, and can eventually lead to failure. Draining the tank removes that sediment.

Why This Matters

Your water heater is probably the second-biggest energy user in your home. Sediment makes it work harder:

• Reduced efficiency – Sediment insulates the heating element from the water
• Higher energy bills – More energy needed to heat water
• Rumbling and popping – Water trapped under sediment boils and bursts
• Shorter tank life – Overheating damages the tank bottom
• Less hot water – Sediment takes up space
• Eventual failure – Tank leaks or heating element burns out

A yearly drain removes sediment before it causes real problems.

How Sediment Forms

All water contains minerals to some degree. When water is heated:

1. Minerals precipitate out of solution
2. They settle to the bottom of the tank
3. Over time, they form a layer of scale
4. The layer gets thicker with each heating cycle

Hard water accelerates this process significantly. Soft water produces less sediment but still creates some.

Step-by-Step Draining

Step 1: Turn Off the Power Source

For Electric Water Heaters:

1. Turn off the breaker at the electrical panel
2. Make sure it’s completely off—this is critical

For Gas Water Heaters:

1. Turn the gas valve to “Pilot” or “Off”
2. Don’t turn it completely off unless you know how to relight the pilot

Step 2: Turn Off the Cold Water Supply

1. Find the cold water inlet pipe at the top of the heater
2. Locate the shutoff valve on that pipe
3. Turn it off (usually perpendicular to the pipe)

Step 3: Let the Water Cool

For safety, let the heater cool for at least 1-2 hours before draining. The water inside is very hot and can cause serious burns.

Step 4: Connect the Drain Hose

1. Locate the drain valve at the bottom of the tank
2. Connect a garden hose to the valve
3. Run the other end to a floor drain, outside, or into a bucket
4. Make sure the hose is secure

Step 5: Open a Hot Water Tap

1. Go to a nearby sink or tub
2. Turn on the hot water
3. This breaks the vacuum and allows the tank to drain

Step 6: Open the Drain Valve

1. Open the drain valve slowly
2. Use a screwdriver if it doesn’t have a handle
3. Let the water drain completely
4. If draining into a bucket, you’ll need to empty it several times

Step 7: Flush with Fresh Water

Once drained:

1. Turn the cold water supply back on briefly
2. Let it run for 30 seconds to stir up remaining sediment
3. Watch the water coming out—it should be cloudy
4. Turn off cold water and let it drain again
5. Repeat until water runs clear

Step 8: Close Everything Up

1. Close the drain valve tightly
2. Remove the hose
3. Close the hot water tap you opened earlier

Step 9: Refill the Tank

1. Turn on the cold water supply
2. Let the tank fill completely
3. Check for leaks at the drain valve

Step 10: Restore Power

For Electric:

1. Make sure the tank is FULL before turning on power
2. Turning on power to an empty tank burns out the element instantly
3. Turn on the breaker

For Gas:

1. If you turned it to “Off,” relight the pilot following the instructions on the tank
2. If you left it on “Pilot,” turn the valve back to “On”

Warning Signs You’re Overdue

• Rumbling or popping sounds when heating
• Hot water runs out faster than it used to
• Water temperature is inconsistent
• Higher than normal energy bills
• Discolored or rusty water
• Visible corrosion around the tank

Why Draining Might Not Work

If your water heater has never been drained, or it’s been many years:

• Sediment may be hardened and won’t drain out
• The drain valve itself may be clogged
• Draining could dislodge chunks that damage the valve

In this case, professional flushing might be needed, or it might be time for a new water heater.

DIY vs. Call a Pro

DIY: Annual draining on water heaters in good condition.

Call a pro: Tanks that haven’t been drained in years, stuck drain valves, or if you’re not comfortable with the process. Also call a pro for tankless water heaters—they require different maintenance. Find a plumber →

How Often to Drain

• Hard water: Every 6 months
• Moderate hardness: Once a year
• Soft water: Once a year still recommended
• After installation: Drain once, then begin annual schedule

The Bottom Line

Sediment is the enemy of water heaters. Draining the tank once a year removes it and keeps your heater working efficiently. It takes an hour or two and costs nothing. Replacing a water heater costs hundreds to thousands. The math is pretty simple.