What happens after draining a water heater?

Author: Al Blanda  |  Last update: Friday, June 27, 2025

Flushing the tank Once all the water is drained, keep the hose in the drain valve and turn the cold water valve at the top of the tank back on to begin the flushing process. The new water running through the tank should flush out any remaining sediment. Keep the valve turned on until the water from the hose runs clear.

What to do after draining a hot water heater?

Remove the hose from the drain valve, and be sure to close the valve. Turn the water supply back on to start refilling the tank. Once the tank is full, turn the power or gas supply to the water heater back on. Remember to turn off the faucet you turned on earlier while draining the tank.

How long does it take for a water heater to refill after draining?

When you use up all of the hot water in a traditional water heater, you will often need to wait anywhere from 30 minutes to two hours or more for the water in the tank to reheat. This is why many people opt to switch to tankless water heaters.

Do I need to open a faucet when draining a water heater?

Opening a hot water faucet will help the water heater drain faster. Some drain valves may be opened with a handle but others require a flat blade screwdriver. Let the water heater drain completely.

What does draining a water heater do?

Keep Your Water Heater Sediment-Free for Best Results

Draining the tank every 1-2 years will help flush sediment buildup and keep things running at peak efficiency.

Correct Way to FLUSH WATER HEATER! 2-Minute Tutorial

How much water should come out when draining water heater?

It's not always necessary to drain the entire hot water tank. Since sediment and buildup settle on the bottom of the tank, you may drain a few gallons of water at a time until most of the sediment is flushed out. This also prevents homeowners from accidently damaging the hot water heater by turning it on without water.

How to tell if a water heater is full?

You'll know when your water tank is full when the hot water tap, which you turned on earlier, runs normally without any residual air coming out.

How long does it take to drain a 50 gallon water heater?

How Long Does It Take to Drain a 50-Gallon Water Heater? Draining a 50-gallon water heater for larger units usually takes 45 to 60 minutes. However, it's worth noting that these are approximations, and the actual time can vary.

Why is the water heater still leaking after shut off?

Common Reasons for a Leaking Water Heater

A cracked or corroded water heater tank. Loose or faulty fittings and pipe connections. Improperly installed temperature and pressure relief valve. Worn out anode rod to protect the hot water tank from corrosion.

Do you leave faucet open when filling water heater?

Open each hot water faucet slowly to allow the air to vent from the Water Heater and piping. A steady flow of water from the hot water faucet(s) indicates a full Water Heater.

How long should it take to drain a 40-gallon water heater?

It only takes about 15 to 30 minutes to completely drain a water heater. A typical 40- to 60-gallon residential tank found in most homes will take no more than 15 minutes. However, larger tanks (80 gallons or more) found in homes with larger families can take longer, usually from 30 to 60 minutes; sometimes more.

Do you open the pressure relief valve when draining a water heater?

While draining the tank, keep the pressure relief valve open. This allows air to enter the tank, facilitating a smoother and faster draining process. It also prevents a vacuum from forming inside the tank, keeping the water flowing consistently and preventing potential damage to the tank structure.

How long does it take for water to clear after replacing water heater?

Step 2: Run the Water

For such systems, you need to run water for only 5-10 minutes, considering that the heaters don't usually store a lot of water. This time will be sufficient to clear out any debris resulting from installation.

How long does it take to refill a hot water heater after draining it?

The time it will take for your hot water heater to refill depends on the water pressure of the home. But as a general rule, it will take 30-40 minutes for a 40-gallon tank to fill up (1 minute/gallon).

Can you damage a hot water heater by draining it?

This is what can happen to your hot water heater if it's been collecting sediment for years, and you suddenly drain it: the water heater will spring a leak.

How to get rid of air in lines after draining a water heater?

Remove air from your pipes in five easy steps:
  1. Turn Off Your Main Water Supply Valve. ...
  2. Open all the faucets in your house. ...
  3. Wait for All Faucets to Run Dry and Flush Toilets. ...
  4. Turn the Main Water Supply Back On. ...
  5. Turn All Faucets Off Again in the Correct Order.

Can I take a shower if my water heater is leaking?

As mentioned earlier, in many cases, it's safe to shower even if your water heater is leaking. Small leaks typically don't affect the performance of the water heater, and you can continue to use hot water as normal until the leak is fixed.

Should I turn off my hot water heater if it is leaking?

If you notice a leak anywhere on or around your water heater, you need to turn this valve off because it stops the tank from filling back up. If you can't turn it off because it's broken or you see water leaking from the valve itself, you'll need to cut off your main water supply.

How much does it cost to flush a hot water heater?

Expect a pro to charge you between $75 and $200 to come to your home to flush your water heater, depending on where you live. While this cost deters many homeowners from performing this annual maintenance, it can extend the water heater's lifespan by years, making it worth the additional cost.

What is the life expectancy of a 50 gallon hot water heater?

While today's water heaters are better designed than older models, they still require regular maintenance in order to prolong their lives. With regular inspection, draining, and flushing, you can expect a gas water heater to last anywhere from 8-12 years and an electric water heater to last anywhere from 10-15 years.

Can you flush a water heater without turning off water?

Step 2: Shut off the Water‍

It's important to wait for the water inside the water heater to cool before flushing as it can remain scalding hot for a long time. You can start this step at night after everyone in your household has no need for hot water.

What are the symptoms of a bad thermostat on a hot water heater?

Signs Your Water Heater Thermostat Is Faulty
  • You have no hot water.
  • You're running out of hot water quickly.
  • The water is too hot.
  • It takes a long time for your water heater to heat the water.
  • You keep having to reset the high-temperature limit switch.

How do I know if my water heater has sediment build up?

Here are some telltale signs of possible sediment buildup in your water heater:
  1. Rumbling, popping, or hissing sounds. ...
  2. The water gets warm but never hot. ...
  3. Cloudy or rust-colored hot water. ...
  4. Leaking or faulty pressure relief valve. ...
  5. Cracks in the tank or connections. ...
  6. Decreased hot water flow. ...
  7. Higher gas or electricity bills.

How long does it take for hot water to come back after it runs out?

Well, it depends on your water heater's recovery rate, which is how long it takes to reheat the water tank once it depletes. On average, an 80-gallon tank water heater can take anywhere from 1-2 hours to recover. However, this is just a ballpark figure.

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