When You Need to Drain a Water Heater

Draining means fully emptying the tank. You'll need to do it before:

Repairs - replacing a heating element, thermostat, drain valve, or anode rod
Moving or replacing the unit - a full 50-gallon tank weighs over 500 pounds
Winterizing - protecting a vacation home or seasonal property from freeze damage
Extended shutoffs - leaving a home vacant with the water off
Emergencies - a failing tank that needs to be emptied before it leaks everywhere

If you're draining as routine maintenance to remove sediment, that's technically a flush - the steps below still apply, but see our flushing guide for how often to do it and why it matters.

The whole job takes 45-90 minutes, most of it waiting for water to drain.

What you'll need:

A garden hose (long enough to reach a floor drain, sump pit, or outside)
A flat-head screwdriver (many drain valves have a slotted stem)
Work gloves - the water starts out hot
A bucket (optional, to check what's coming out)

One tip before you begin: if your heater is more than 10 years old, check its age first with our free serial number decoder. Very old tanks sometimes have brittle drain valves that won't reseal, and if the unit is near the end of its life anyway, it may be smarter to put the effort toward replacement than maintenance.

Step 1: Turn Off the Power or Gas

Electric: switch off the water heater's breaker at the electrical panel. This is non-negotiable - if the elements heat with the tank empty, they burn out in seconds.
Gas: turn the gas control knob to "Pilot" (or "Off" if you're comfortable relighting the pilot afterward).

Step 2: Turn Off the Cold Water Supply

Close the shutoff valve on the cold water line entering the top of the tank. If there's no dedicated valve (some older installs), shut off the main water supply to the house.

Step 3: Let the Water Cool (or Use Some Hot Water First)

Tank water is 120-140°F - hot enough to scald. The safest approach is to shut things off in the evening and drain the next morning. In a hurry? Run a hot shower or two first to pull the temperature down, and wear gloves.

Step 4: Connect a Garden Hose to the Drain Valve

The drain valve is the spigot near the bottom of the tank. Thread the hose on hand-tight and run the other end to a floor drain, sump pit, utility sink, or outside. Keep the outlet lower than the valve - gravity is doing the work.

Step 5: Open a Hot Water Faucet Upstairs

Open the hot side of a faucet somewhere above the heater (a second-floor bathroom is ideal). This breaks the vacuum so the tank can drain, like lifting your finger off a straw.

Step 6: Open the Drain Valve

Open the valve (use the flat-head screwdriver if it has a slotted stem) and let the tank empty. A full 50-gallon tank typically takes 20-40 minutes, longer if sediment slows the flow.

Step 7: Rinse Before Refilling (Optional but Smart)

Since the tank is already empty, take two extra minutes: turn the cold supply on for 30-60 seconds with the drain valve still open so the incoming water pushes loose sediment out the hose. If you're draining for a repair or a move, this keeps debris out of the valve when you close it. Skip this only if you're in an emergency drain situation.

Step 8: Close Up and Refill

(Skip the refill steps if you're winterizing or moving the unit - leave the tank empty with the drain valve open.)

Close the drain valve and remove the hose.
Leave that upstairs hot faucet open.
Turn the cold supply back on and let the tank fill.
When water flows steadily from the open faucet (no sputtering air), the tank is full. Close the faucet.

Step 9: Restore Power or Gas

Only after the tank is completely full:

Electric: flip the breaker back on.
Gas: turn the control back to "On" and relight the pilot if needed.

Hot water returns in about 30-60 minutes for gas, 60-120 minutes for electric - here's what recovery time is normal.

Step 10: Check for Leaks

Inspect the drain valve over the next day. A slow drip usually means debris on the valve seat - open and close it once to clear it, or cap the outlet with a garden hose cap as a backstop.

Troubleshooting

Nothing Comes Out of the Drain Valve

Sediment is blocking the opening - common on tanks that have never been drained. Try these in order:

With the valve open, briefly turn the cold supply on to blast water backward through the blockage.
Push a stiff wire or straightened coat hanger through the open valve to break up the clog (wear gloves).
Attach the hose, close the far end, fill the hose with water, and give it a sharp squeeze or "whip" to shock the clog loose.

If the tank is so full of sediment it won't drain at all, that's a strong sign of advanced buildup - see the other symptoms of sediment problems and consider a professional service call.

The Water Comes Out Brown or Full of Debris

Normal for a first-ever drain - that's exactly what you're removing. Keep flushing until clear. If your hot water is discolored at the tap during normal use, though, that can also signal corrosion.

The Drain Valve Won't Close or Keeps Dripping

Plastic drain valves on older units are notorious for this. Cap it with a brass hose cap as a temporary fix; a plumber can replace the valve with a brass one in under an hour.

Draining vs. Flushing: What's the Difference?

Draining means emptying the tank - for repairs, moving, winterizing, or emergencies. Flushing means draining plus running fresh water through to carry sediment out, and it's what you want for routine maintenance. If maintenance is your goal, head to our dedicated guide on how often to flush a water heater - it covers the schedule for your water type and the signs your tank is overdue.

Winterizing Tip: Leave It Empty the Right Way

If you're winterizing, drain the tank fully, leave the drain valve open, and leave a hot faucet open somewhere in the house so trapped water can expand without cracking anything. For gas units, turn the gas control fully off. When you return, refill the tank completely before restoring power or gas - heating an empty tank destroys electric elements instantly.

When to Call a Professional

The drain valve is seized, brittle, or won't stop leaking
The tank won't drain even after clearing attempts
You see signs of a leaking tank body - a leak from the bottom usually means the tank itself has failed
The unit is past 10 years old and showing failure warning signs - money is better spent on replacement

Not sure how old your unit is? Check its age free in seconds - the answer is hiding in the serial number.

How to Drain a Water Heater (Step-by-Step Guide)