How Long Does It Take to Drain a Water Heater?
Getting the most from your water heater is no sweat
Your home’s water heater has a finite life span, and draining it can help extend its life and keep it running efficiently. But how long does it take to drain a water heater? Learn more about this essential home component so your water heater can reach its full potential. Plus, if your unit runs smoothly, you’ll save some money on utility bills.
Why Drain and Flush a Water Heater?
Draining the appliance will help it operate as efficiently as possible and maximize the hot water available at any given time. Doing so empties the tank and pushes out residue left by minerals in your home’s water supply. With your water heater drained, you can take the time to flush it out for even better results. Flushing your water heater doesn’t empty the tank but involves dislodging and removing the stuck-on sediment left behind.
As a bonus, draining your water heater allows you to get up close and personal with it, check the safety features, and ensure that all is well with the appliance.
How Long Does Draining a Hot Water Heater Take?
Depending on the size of your water heater, draining it completely takes 10 to 30 minutes. However, there are other steps you should perform after draining the appliance. Flushing a traditional tank-style or tankless water heater only takes minutes, but filling the tank and waiting for the water to heat up adds a good chunk of time to the overall task.
The total time to set up, drain, flush, refill the system—and return to everyday life and warm showers—is about two hours.
How Often Should I Drain and Flush My Water Heater?
Regardless of your unit type, draining and flushing a water heater once a year is crucial to control scale buildup, ensure efficiency, and extend the life of your unit. If you live in an area with particularly hard water, consider draining and flushing your water heater every six months.
When to Reconsider Draining Your Water Heater
Completely draining and flushing your tank-style water heater is the best way to promote optimum efficiency and prolong the appliance's life. However, sometimes draining a water heater can cause more trouble than it fixes.
If this is the first time anyone has serviced your water heater in several years, draining it can dislodge sediment that’s keeping it from leaking. When sediment builds up, it can create hot spots in the tank that can develop into tiny holes. The debris you’re about to remove can, in reality, be blocking water from escaping. Therefore, draining the heater could cause irreparable leaking.
Before proceeding, consult a local water heater specialist for the best way to handle the situation if you haven’t drained your water heater in a long time.
How to Drain a Water Heater
Draining your water heater should be similar whether you have a tank or tankless model. Of course, you'll want to refer to your manufacturer's manual before attempting a DIY draining. Here's a look at the basics to get you started:
Turn off the gas or electrical supply to the appliance.
Close the supply valve.
Open the hot water side of several faucets around the house.
Connect either a hose or hose and liquid transfer pump to the heater's drain valve.
Next, extend the drain hose to the outside of the house in a spot where you won't mind water flushing out.
Test the heater's pressure valve by opening it to listen for released air.
Open the drain valve. If necessary, turn on the transfer pump. Be sure to allow the heater to drain entirely. For a tankless water heater, this can be a good opportunity to clean the filter.
Turn the water supply "on and off" several times to flush the water heater.
Close the drain valve, disconnect the hose, close the faucets, and open the water supply valve.
Turn the water heater back on. Give it about an hour for the water in the tank to get hot again.
Why Won’t My Water Heater Drain?
If your water heater drains slowly, or not at all, the sediment has likely become thick enough to block the drain valve outlet. Not to worry, though; that’s why you’re draining and flushing it now.
If it’s draining slowly, wait it out. As long as some water is making its way out of the valve, it will eventually completely drain. If it’s been a while since anyone’s paid attention to the heater, or if you have hard water, consider draining it more often to avoid sediment building up around the outlet.
If no water comes out of the hose end, try opening the temperature and pressure valve. There may be an air pocket high in the tank that won’t allow the water to drain until the air can expand. When this happens, opening the valve can disrupt the air bubble and get the water moving. If that doesn’t solve the problem, you’ll likely have to call a local water heater repair pro to take a look at the problem.
How to Refill the Water Heater
Like any interaction you have with your water heater, this one requires you to consult your manufacturer's manual before you start. However, there are some nearly universal steps to get familiar with before you start this project. Prepare for this process by shutting off the power to your water heater. This will be done by either turning off the gas valve or shutting down your electrical breaker. Here's what to do once the power is off:
Connect a routing hose to the drainage valve.
Open the drainage valve using a counterclockwise motion.
Turn on the faucet to your hot water somewhere inside your home.
Shut the drainage valve.
Using cold water, begin the process of filling your hot water heater.
Look for a steady flow of water coming from the faucet you used to test for hot water somewhere inside your home. If this faucet now has a steady flow of water coming from it, your tank is full.
Restore power to your water heater.
How Long Do Water Heaters Last?
Traditional tank-style water heaters last between 8 and 15 years with proper maintenance, while tankless heaters can last up to 20 years with good care.
Typically, signs of water heater failure include diminishing hot water levels, leaks, cloudy water, or strange sounds. If you notice any of these issues, have a water heater pro take a look before you need a replacement.
DIY vs. Hiring a Pro
DIY draining and flushing a water heater shouldn’t cost anything once you have the necessary equipment—including a garden hose, liquid transfer pump if required, a wrench or screwdriver, buckets, and rags. However, the job does take time to complete. If draining and flushing your water heater doesn’t sound like a fun way to spend Saturday afternoon, a nearby plumber can perform the task for roughly $200.
Call a pro to drain, flush, and inspect the unit if you suspect something is amiss with your hot water heater. If the issue is fixable, expect an average water heater repair cost of $220 to $960, while the cost of replacing your water heater will range from $840 to $1,680.
Questions to Ask the Water Heater Pro
If you're planning to leave the task of draining your water heater to a pro, it's important to ask the right questions when calling a plumber. Start by asking about the types of water heaters they service to ensure that your model is on their roster. Here's what else to ask to make sure you're dealing with the right company:
Is your company fully licensed and insured?
How much do you charge for a basic water heater flush cost?
Do you offer maintenance packages that include this service each year?
Will you be able to fix or replace any water heater components that you discover are damaged or outdated during a flush visit?
How long will a visit take?
When looking for the right water heater pro to flush your water heater, it's always smart to reach out to multiple companies. Most experts recommend getting at least three quotes. This will help you get an idea of what a reasonable price for a hot water heater flush looks like.
Deane Biermeier contributed to this piece.