How to Empty a Hot Water Heater

Draining your hot water heater might sound like a task best left to the pros, but it’s actually one of the easiest and most rewarding DIY plumbing tasks you can do. Whether you’re doing it for annual maintenance, to get rid of sediment, or to prepare for storage or replacement, knowing how to empty a hot water heater properly can save you money, improve efficiency, and extend the lifespan of your appliance.

Let’s walk through everything step-by-step so you can do it safely, quickly, and with total confidence.

Why You Should Empty Your Hot Water Heater

Most people don’t think twice about their water heater—until the hot water runs out or the system starts making strange popping noises. These are clear signs that your unit may need to be drained. But why wait for problems when a bit of routine maintenance can prevent them altogether?

Tools and Supplies You’ll Need

Before you begin, it’s best to gather all your supplies in one place. Draining a water heater isn’t overly complicated, but it’s much easier with the right tools.

Essential Tools List

Here’s what you’ll absolutely need:

Garden hose (long enough to reach a drain, bucket, or safe outdoor area)
Flathead screwdriver (to open the drain valve)
Bucket (to collect sediment or catch drips)
Towel or rags (to clean up any spills)
Gloves (optional but recommended for safety)
Flashlight (to inspect the area around the tank)

These basics are usually enough to get the job done.

Optional Items for Easier Draining

If you want to make the job even smoother:

Shop vac: To remove stubborn sediment that doesn’t drain easily
Pipe wrench: In case the hose connection is tight or old
Teflon tape: To reseal fittings if needed afterward
Water softener or descaling solution: For flushing hard water buildup

Having these extras on hand can make the whole process cleaner and faster.

READ MORE: How to Turn On a Hot Water Heater

Safety Precautions Before You Begin

Before you touch a single valve, there are a few safety steps you must take. These are crucial to prevent burns, electrical shocks, or water damage.

Turning Off the Power or Gas

If your water heater is electric:

Locate the circuit breaker labeled “Water Heater” and switch it OFF. This prevents electric shock and protects the heating element during draining.

If it’s gas:

Turn the gas control knob on the heater to the “Pilot” or “Off” position.
For added safety, you may also shut off the gas supply valve completely.

Never attempt to drain a heater that is still powered on or heating. It’s a serious safety hazard.

Letting the Water Cool Down

This is a step many people skip, and it’s a painful mistake. Water inside the heater can reach up to 140°F or more. That’s hot enough to cause severe burns.

Turn off the heater and wait 2–3 hours, or ideally overnight, to let the water cool down.
You can speed up the process by running hot water from a nearby faucet for several minutes.

Once the water is cool to the touch at the faucet, you’re safe to start draining.

Step-by-Step Guide to Emptying a Hot Water Heater

Now that everything is prepped and safe, let’s walk through the draining process.

Step 1 – Shut Off Power and Water Supply

We already mentioned turning off power or gas. Now shut off the cold water supply valve located above the water heater. This prevents more water from entering the tank during the draining process.

Double-check that the power is off and that the gas is shut off or set to “pilot.”

Step 2 – Connect a Garden Hose to the Drain Valve

Locate the drain valve at the bottom of the heater. It usually looks like a standard hose bib. Connect your garden hose to it and run the hose to:

A floor drain
A large bucket
A safe spot outside (if feasible)

Make sure the hose is securely attached to prevent leaks and spills.

Step 3 – Open the Pressure Relief Valve

This step is key for proper drainage. Locate the T&P (temperature and pressure) relief valve, typically on the side or top of the tank. Open it to allow air into the system so water can flow freely out the drain.

If your heater doesn’t have a manual valve, you can simulate this by opening a hot water faucet elsewhere in the house.

Step 4 – Open the Drain Valve and Empty the Tank

Now it’s go time.

Slowly turn the drain valve counterclockwise using a screwdriver or your hand.
You should see water start to flow out through the hose.

Let the tank drain completely. This can take 15–30 minutes depending on size and flow rate.

If the water flows slowly or stops before the tank is empty, it could mean a clog at the drain valve. In that case, gently poke inside with a wire or use a shop vac to remove sediment.

READ MORE: How to Shut Off a Hot Water Heater

How to Flush the Tank After Draining

Draining your hot water heater is a great start—but if you want to really get rid of sediment, a full flush is where the magic happens. After the tank is emptied, the leftover residue needs to be rinsed out to prevent it from settling again. Let’s walk through how to do that properly.

Step-by-Step Tank Flushing Process

Once the water has been drained completely:

Leave the drain valve open and the hose connected.
Turn the cold water supply back on briefly.
- This causes fresh water to rush into the bottom of the tank and flush out remaining sediment through the hose.
Watch the water exiting the hose.
- If it’s cloudy, brown, or has visible particles, keep flushing.
- Let it run until the water is clear.
Repeat as needed. You might need to cycle the cold water on and off a few times to stir up stubborn debris.

Be patient. The cleaner the water that exits, the better your water heater will perform going forward.

Removing Remaining Sediment Effectively

Even with flushing, you may notice some grit or sludge clinging to the bottom of the tank. Here’s how to get rid of it:

Use a shop vacuum if you have one. Remove the drain valve temporarily and insert the vacuum hose directly into the opening.
Agitate with a tool. A long brush or coat hanger (be gentle!) can stir the sediment to help flush it out with one final rinse.

Never use harsh chemicals or sharp objects inside the tank. The glass lining inside is delicate and can be damaged easily.

Refill and Restart Your Water Heater

You’ve done the dirty work—now it’s time to bring your water heater back to life. The restart process is as important as the draining itself.

Turning Water Supply Back On

Start by:

Closing the drain valve tightly and removing the garden hose.
Turn the cold water supply valve back on slowly.
Open a hot water tap in the house to release air trapped in the tank.
- You’ll hear sputtering and see bubbles—that’s normal.
- Once water flows in a steady stream, the tank is full.

Do not restore power or gas until you’re certain the tank is full. Running a dry heater can fry electric elements or crack a gas burner.

Restoring Power or Relighting the Pilot

Once the tank is full:

For electric heaters: Flip the breaker back ON.
For gas heaters:
- Follow the manufacturer’s instructions to relight the pilot light.
- Once the pilot is stable, turn the gas control knob back to “ON.”

Now your heater is operational again. In 30–60 minutes, you’ll have hot water, and your heater will run more efficiently than ever.

READ MORE: Do Dishwashers Heat the Water?

How Often Should You Empty Your Water Heater?

You might be wondering how often this chore needs to be on your calendar. The answer? It depends on your water quality and heater type.

Recommended Frequency Based on Water Type

Hard water areas (with high mineral content): Every 6 months.
Moderate to soft water: Once per year is generally sufficient.
Tankless water heaters: Descaling every 12 months, not draining.

If you’ve never done it before and your heater is over 3 years old, start now—better late than never.

Signs It’s Time for a Drain

Rumbling or banging noises during heating
Water taking longer to heat
Less hot water available
Cloudy or rusty water
Higher energy bills

These are your heater’s way of begging for maintenance. Regular draining will solve most of these problems—or prevent them from happening in the first place.

Common Problems and How to Fix Them

Even with careful preparation, sometimes things don’t go as planned. Here are the most common hiccups and how to handle them.

Drain Valve Clogs

If no water is coming out after opening the drain valve:

Shut the valve and water supply.
Try poking the valve gently with a wire or coat hanger.
Use a shop vac on reverse to force air into the tank and dislodge the clog.

If it’s still blocked, you might need to replace the drain valve. This is a simple part you can find at any hardware store.

Water Won’t Drain Fully

If the water slows down and won’t completely empty:

Check for air lock: Open a hot water faucet or the T&P valve to allow air in.
Sediment buildup at the base may be blocking flow. Agitate the tank gently or use a vacuum to remove it.
Your hose may be too long or sloped upward, which can slow or stop the siphon effect. Try repositioning or shortening it.

Don’t force anything. Be gentle, especially around older units where fittings can become brittle.

When to Call a Professional

While draining a hot water heater is usually a manageable DIY task, there are some situations where it’s safer, smarter, and ultimately more cost-effective to let a licensed plumber take over.

Leaks, Noises, or Persistent Issues

If you notice any of the following after draining or during inspection, call in a professional:

Leaking around the tank base – This could indicate internal tank corrosion, which usually means it’s time for a full replacement.
Unusual noises after flushing – Some popping or crackling is normal with sediment buildup, but loud banging, whistling, or hissing after draining could mean there’s internal damage.
Water that remains discolored or smells metallic – This may suggest problems with the anode rod or the tank liner.

If these symptoms continue after a flush, there’s likely more going on inside than just sediment, and a trained eye is needed to avoid costly or dangerous outcomes.

Replacing Faulty Drain Valves or Heating Elements

Over time, drain valves can corrode or break, especially if you’ve never used them before. If your valve:

Won’t open
Leaks from the handle
Is completely clogged

…it’s best to have it replaced professionally. The same goes for heating elements in electric units. Replacing these parts involves working with water and live electricity—not a job for beginners.

Also, any repairs involving gas lines, pressure valves, or electrical rewiring should always be done by a licensed technician.

Conclusion

Emptying a hot water heater might seem like an intimidating job, but it’s one of the easiest, most effective forms of home maintenance you can do. With just a garden hose, a few tools, and a bit of patience, you can dramatically improve your water heater’s performance and lifespan.

From removing sediment to flushing out buildup and resetting your system, the process is simple and safe when done correctly. Plus, the long-term benefits—lower bills, faster hot water, fewer repairs—make it well worth your time.

Don’t wait for your heater to start acting up. Drain it regularly, and it will keep the hot water flowing for years to come.

FAQs

1. What happens if I never drain my water heater?
Over time, sediment builds up inside the tank, reducing heating efficiency, clogging valves, causing strange noises, and eventually damaging the tank—potentially leading to leaks or total failure.

2. Can I drain my water heater while it’s hot?
Technically yes, but it’s dangerous. Hot water can cause burns, and sudden cold water flushing into a hot tank can crack the internal lining. Always let the water cool for a few hours first.

3. How long does it take to empty a water heater?
Most residential tanks (40–50 gallons) take around 20–30 minutes to fully drain, depending on water pressure, hose length, and sediment levels.

4. Is draining a water heater messy?
It doesn’t have to be. As long as your hose is secured and draining to a safe area, and you take care to control valve openings, the process can be clean and controlled.

5. Can I reuse the drained water for anything?
If the water is clean and cool, you can use it for watering plants, rinsing driveways, or flushing toilets. Just don’t use it for drinking, cooking, or bathing.