Leaking water heater in Phoenix: Home Fix Neighbor

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Okay, the leak's stopped. Now what?

If you followed along with the video, the heat's off, the water to the tank is off, and the leak has stopped. Nice work. Here's what comes next.

1. Get the standing water up. Towels do the job, but a wet/dry vacuum is a lot faster³.
2. Dry everything out within a day or two. That's your window before mold gets a foothold⁴. Run fans, and if you've got one, a dehumidifier. A moisture meter will tell you when the drywall and floors are actually dry, not just dry to the touch.
3. Move anything that got wet away from the tank so it can dry too.

So why did this happen?

Most leaks start small and get worse, and a big one can flood a house in a few hours³. So the fact that you caught it matters.

Where the water's coming from tells you a lot:

• The bottom of the tank? That usually means the steel has rusted through. You can't patch a rusted tank, so it's time for a new one³.
• The drain valve or a pipe fitting? Better news. That's often just a worn washer or a loose connection that needs a little tightening or a new part³.

Here's what's going on inside. Minerals in your water slowly settle at the bottom of the tank. There's also a metal rod in there, called the anode rod, whose whole job is to rust so your tank doesn't. Once that rod's used up, the tank starts rusting instead. Most tanks last somewhere around 8 to 20 years, depending on the type³.

What's different here in Phoenix

Phoenix water is hard. Like, really hard. The city's own 2025 water quality report measures it at 172 to 302 parts per million⁵. For comparison, the U.S. Geological Survey calls water under 60 soft, 61 to 120 moderately hard, 121 to 180 hard, and anything over 180 very hard⁶. So Phoenix water sits mostly in the very hard range, and its softest readings are still hard.

Hard water speeds up the mineral buildup that wears tanks out³, so water heaters here can wear out faster than in places with soft water.

Permits: if a licensed contractor replaces your water heater, you don't need a city permit. If you're replacing an electric one yourself, you do⁷.

Gas emergencies: Southwest Gas's number is 877-860-6020. Call it and 911, from outside¹.

Calling a plumber (and what to ask)

Get a licensed plumber out today. If the leak is coming from the tank itself, you're most likely looking at a replacement³. And if a gas water heater is leaking near the burner or the gas line, don't wait on that one at all³.

A few things worth asking when they call you back:

• Is it the tank, or a valve or fitting?
• Can you fix it, or does it need replacing?
• Can you come today?
• Do you work with my home warranty or insurance?

Can you fix it yourself?

Maybe, if it's a drip at the drain valve or a pipe fitting. That's usually a worn washer or a loose connection³. If the tank itself is leaking, though, that's a job for a plumber. And here in Phoenix, swapping out an electric water heater yourself needs a city permit⁷.

Watch the video below first, then use the steps under it.

These steps assume you already did what our video at the top of the page showed: the heat's off and the cold-water valve is closed. They follow the same order as the how-to video above. Plan on a few hours without hot water, and have your new valve on hand before you start⁸.

1. Let the water cool down. The water inside stays hot for hours, so give it time before you drain anything³.
2. Open a hot water tap. Turn on a hot faucet somewhere in the house. It'll run for a few seconds, then stop as the pressure lets off⁸.
3. Hook up a hose and drain the tank. Attach a garden hose to the drain valve, run the other end to a floor drain or outside, away from the house, and open the valve. Most tanks take 20 to 30 minutes³.
4. Not draining? Let air in. Water can't flow out unless air can get in. If the open tap isn't enough, lift the lever on the tank's pressure relief valve to let air in⁸. If the flow slows down early, sediment may be clogging the drain valve, so open and close it a few times to clear it⁸.
5. Close the drain valve and get towels ready. Once it's down to a trickle, close the drain valve and take off the hose. Put towels down and keep a small bucket handy. A little water always stays in the tank below the valve opening, and it comes out when the valve does⁸.
6. Unscrew the old valve. Turn it counterclockwise with pliers or an adjustable wrench and catch the leftover water in the bucket. Then scrub the threads in the tank with an old toothbrush or a small wire brush so the new valve seals well⁸.
7. Put the new valve together. Lots of water heaters come with a plastic drain valve, and those can clog up or leak, so this is a good time to upgrade to a brass ball valve⁸. Match the size of your old valve (the one in the video is 3/4-inch). You can grab a ready-made full-port brass drain valve, or build one like in the video from a 3/4-inch full-port brass ball valve, a 3-inch brass pipe nipple, a brass garden hose adapter and a brass hose cap. Wrap the threads with thread seal tape in the same direction you'll screw them in, so the tape doesn't bunch up and peel off. Skip the tape on the hose cap: it has its own rubber washer, so just turn it finger-tight⁸.
8. Screw it in. Thread it in by hand, then give it about one more full turn with the wrench. Snug is enough. Before you finish, make sure the handle will have room to open and close without hitting anything⁸.
9. Refill it before you turn the heat back on. This one's important. If you opened the pressure relief valve, close it. Keep that hot tap open and turn the cold water back on. The tap will sputter air at first. Once it's running water steadily, turn it off⁸. Don't turn the power or gas back on until the tank is full⁹.
10. Check for leaks. Feel around the new valve for any wetness. Then hook up the hose, open the valve for a few seconds to make sure it works, close it, and check again before you put the cap back on⁸. If you see a drip from the bottom of the tank itself, the tank is rusting through and needs replacing. Time to call a plumber³.
11. Turn the heat back on. Flip the breaker back on, or turn the gas control back to where it was. If the pilot went out, relight it the way your owner's manual says⁸.

Insurance and warranty: find it and use it

Good news: you might already be covered, maybe even more than one way. Every policy and warranty is different, so take a look at yours before anyone starts work. (This is general info, not advice about your specific coverage.)

First, figure out what you've got.

1. The manufacturer's warranty. There's a label on the side of your water heater with the model and serial number. Snap a photo of it, then look up the warranty on the maker's website with that serial number handy³.
2. A home warranty. Lots of people get one when they buy their house and totally forget about it. Search your email and your closing papers for "home warranty." Just know it's a service contract, not insurance¹⁰. It's also worth checking whether a builder's warranty or your credit card covers it¹⁰.
3. Home insurance. Pull up your policy in your insurer's app or email and find the page that lists your coverage and your deductible.

Got a home warranty? Here's how to use it.

1. Call them before you hire anyone. You request service by phone¹¹.
2. They'll usually send their own contractor. You generally don't get to pick¹⁰.
3. Ask about costs up front. A lot of them charge a fee for each visit, often $75 or more¹⁰. There can be limits on what they'll pay¹⁰, and some will only repair, not replace¹⁰.
4. Can't get them out fast enough? Waiting can cost you money and hardship¹⁰, and leaks don't wait. Ask them in writing if you can use your own plumber. Then book one of our vetted pros in Phoenix.

Shopping for a home warranty for next time? Check out our guide to choosing a home warranty.

Water damage? Here's how to use your home insurance.

1. Take photos before you clean up, including where the water came from¹².
2. Compare the damage to your deductible. You pay the deductible first, so a small claim might not be worth it¹².
3. Call your insurer and report it. They may send out a plumber or a water cleanup company¹².
4. Hang on to every receipt for repairs and cleanup.

Shopping for home insurance? Check out our guide to comparing home insurance.

Keeping it from happening again in Phoenix

A little maintenance goes a long way, especially with Phoenix water.

• Flush the tank every one to three years, depending on the model and your water⁹. With water this hard, aim for the shorter end.
• Soften your water. Hard water speeds up the corrosion that kills tanks³. A whole-house water softener pulls those minerals out before they ever reach the tank.
• Test the relief valve once a year. Lift the little lever and let it snap back³.
• Check the anode rod and replace it when it's worn³. Replacement anode rods come in different sizes for different tanks.
• Get a heads-up next time. A drain pan under the tank and a water leak alarm on the floor will tell you something's wrong early. A smart water monitor with automatic shut-off can even turn the water off for you.

You might run into these too

• Water heater rumbling or popping
• Water heater failure: no hot water
• Water heater relief valve dripping
• Mold after water damage
• Water-damaged or warped floors

Sources

1. Southwest Gas: natural gas leak safety
2. Safe Electricity: flooding safety
3. A. O. Smith: What to do when your hot water heater is leaking
4. US EPA: A brief guide to mold, moisture and your home
5. City of Phoenix: 2025 water quality report
6. U.S. Geological Survey: hardness of water
7. City of Phoenix: residential permits
8. AmplifyDIY: How to replace a hot water heater drain valve (video and description)
9. City of Blaine, MN: water heater flushing
10. DC Attorney General: consumer alert on home warranties
11. California Department of Insurance: home protection contracts
12. Policygenius: how to file a home insurance claim for water damage