How Long Does It Take To Drain A Water Heater?

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If you're a relatively new homeowner with a water heater tank at home, then you might ask yourself how long it takes to drain. It might seem like a daunting task at first but don't worry. We did the research and asked professionals how long it normally takes to drain a water heater at home.

On average, it takes around 5 to 15 minutes to drain a water heater at home. The duration will vary based on several factors though. Also, this doesn't account for the preparation time needed to drain a water heater.

In this article, we will discuss what those factors are and what you need to know about them. Additionally, we will also talk about why you should drain the water heater at home and how often you should do it. So, without further ado, continue reading on to find out more.

How Long Does It Take To Drain A Water Heater?, How Long Does It Take To Drain A Water Heater?

How Long It Takes To Drain A Water Heater?

Female hand puts thermostat of electric water heater (boiler) in economy mode. Household enegry saving equipment

First, you need to understand that four factors affect the time it takes to drain a water heater. Based on the following factors, it would take between 5 to 15 minutes to drain all the water out.

Tank Capacity

The general rule to remember is that the larger the tank, the longer it takes to drain its contents. Naturally, this means that a 40-gallon water heater tank would drain faster than say, a 60-gallon water heater tank.

So, if everything else is equal on all other fronts, the one with the smaller capacity would drain much faster. But nowadays, a lot of water heater tanks come with a high-pressure water valve installed so larger water tanks are not as daunting as they initially look.

Drain Valve Type And Size

Similar to the water tank, the size of the valve affects how fast you can drain the water out. So, a wider drain valve equates to a faster drain time.

Additionally, most homeowners and plumbers prefer using a brass drain valve over their plastic counterparts. They are a bit more expensive but the strength and durability that they offer are more than make up for it.

Also, brass valves come in two different types, ball valves, and gate valves. The former is the more expensive option between the two but it allows for a much faster water-draining experience.

Water Pressure

A water heater with a high flow rate will generally drain much faster than one with a lower number.

Generally, water heater tanks at home have a flow rate between 9 and 17 gallons per minute (GPM). This means that a water heater tank with a flow rate of 12 GPM would greatly outpace a water heater tank with 9 GPM, provided that everything else is equal.

So, say that you own a 90-gallon water tank. If it has a flow rate of 9 GPM, it would take you around 10 minutes to completely drain out all the water. Bear in mind though that this number changes based on the diameter of your drain valve.

Sediment Build-Up

Minerals like magnesium and calcium inside the water tank turn into sediment particles naturally through the process of water heating. What ends up happening is that they settle down at the bottom and, if not taken care of properly, they become an obstruction when it comes to draining water.

Additionally, sediment build-up can also cause leakage. Not only that, the water temperature inside the tank fluctuates from being too hot to being too cold at times. Periodic flushing would help avoid this issue.

Another way to prevent sediment build-up is by installing a water filtration system. This would prevent these minerals from settling at the bottom and clogging the drain valve. This helps ensure that your water heater tank is running at optimal efficiency always, and prevents damages to occur over time.

How Much Time Needed To Drain A 40-gallon Water Heater?

Tank for indirect heating of boiler, flow filter for fine cleaning, boiler piping and meters in boiler room of private house

On average, it will take around 3 to 5 minutes to completely drain a 40-gallon water tank. As mentioned earlier, there are other factors that you need to consider so the time needed may vary depending on the water heater's water pressure and drain valve.

Additionally, this does not include the preparation time needed to drain the water. So while the draining process takes a relatively short amount of time, it may take longer overall.

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How Much Time Needed To Drain A 50-gallon Water Heater?

Taking into account the average flow rate of a water heater that we discussed earlier, it would take around 5 to 9 minutes to completely drain out all of the water. And just like the 40-gallon water heater, that drain time would still vary depending on the water tank's drain valve. So, the larger the diameter of the valve, the faster the process would take.

And remember, this does not include the preparation and finishing time needed. So, the quicker you prepare everything when it's time to drain your water heater tank, the faster everything will go.

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Why Drain A Water Heater?

Residential Water Heater with the panel removed for repairs or adjustments to the thermostat

As mentioned earlier when discussing the factors that affect the water-draining process, sediments can become a major obstacle. They clog up the drain valves and when left for too long, they will eventually lower the water heater tank's efficiency and cause leakage.

That's why it's important to regularly drain your water heater tank. Doing so allows you to clean up the interior of the tank and scrub away any sediment build-up that may have formed at the bottom of the tank.

Also, take note that seeing these sediments doesn't mean that your water was contaminated. In reality, water is never clear as stated by the United States Geological Survey. Water gets treated at a facility but it is not purified from these naturally occurring minerals.

How Often To Drain A Water Heater?

On average, it's best to drain your water heater at least once a year. But only if you have a water filtration system. If not, you might need to drain your water heater tank every 6 to 8 months instead, depending on how often sediment build-up occurs.

If you don't have a water filtration system, we suggest installing a water softener or a sediment filter. Both work well in preventing sediment build-up inside your water heater tank.

A water softener works by catching those naturally occurring minerals and trapping them in a bed of resin beads. Through a process of ion exchange, these beads act like a sort of magnet. Those minerals have a positive charge while the resin beads have a negative charge, causing them to be attracted to one another.

Sediment filters on the other hand though are less effective but still prove to be useable. They prevent minerals larger than their pore size from passing through. However, this means that smaller particles can still pass through these filters now and then.

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Check this sediment filter on Amazon.

How Long Does A Water Heater Take To Flush?

It takes around 10 to 20 minutes to flush out the water inside your water heater tank. Do remember though that draining and flushing are fundamentally different.

When you're draining, you are completely emptying the water tank of its contents. On the other hand, flushing drains the contents inside your water tank only for it to be replaced soon after.

The goal with flushing is that you're trying to verify whether there are impurities inside the water. Other times, it's to prevent water from going stale. The time needed to flush your water heater tank depends on how you feel about the water quality, as you want to make sure that everything is in good condition.

Also, do take note that both flushing and draining should be done regularly. This is to prevent sediment build-up and to maintain the water quality inside your heater tank.

In Conclusion

House water heating boiler with pump, ball valves and filters

On average, it would take you at least 5 to 15 minutes to drain the water heater tank at home but if you own one that's around 50-gallons, it would take around 3 to 9 minutes. This of course is subject to change based on the factors that we had discussed. And, this doesn't account for the preparation and finishing time required when draining a water heater tank at home.

An important thing to remember is that periodically draining your water heater tank at least once every year is important. This prevents leakage and efficiency issues. Not only that, it helps maintain the water's quality as well.

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