Hot Water Heater Leaking? Here's What to Do

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Figure out what's causing the leak, how to fix it, and when to call a pro
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If your water heater is leaking, don’t panic—in some cases, the problem can be easily fixed with a screwdriver or a replacement part. In this article, we’ll walk you through what to do if you notice your water heater leaking and how to figure out where the leak is coming from. We’ll also help you figure out whether you can fix the problem yourself or if you should call a pro.

Why is my water heater leaking?

  • Loose pipes : The pipes that move water to and from the water heater can become loose and leak.
  • Pressure valve : The valve that regulates the temperature and pressure inside the tank can get stuck open.
  • Drain valve : The drain valve might be open, or it could be broken.
  • Cracks and rust : If the body of the tank is cracked, it won’t be able to hold water.
Section 1 of 6:

First Steps if Your Water Heater is Leaking

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  1. It’s normal for condensation to form on the outside of a water heater. If you only see a little water, watch to see if it eventually evaporates. If it does, it’s probably condensation. If the water pools without evaporating, it’s likely a leak. [1]
    • You can also wipe away the water and watch to see how it returns. If it comes back evenly on the side of the tank, it’s condensation. If the water comes back in drips or rivets, it could be a leak.
  2. If you have an electric water heater, turn off the power at the breaker. If you have a gas heater, turn off the gas valve—this will usually be a lever on the gas line. [2]
    • You can also shut off the gas by turning the knob on the gas control panel on the water heater tank.
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  3. If water is pouring or spraying out of the water heater, turn off the water supply to prevent flooding. But if the water seems to be leaking slowly, leave the water on—it may make it easier to find the source of the leak. [3]
    • The water shut-off is typically a lever or knob on the cold water pipe near the top of the tank. If you can’t find it, check the owner’s manual for your specific heater.
  4. Pressure can build up inside your hot water heater, which can be dangerous when you’re working on it. To release some of that pressure, either lift the lever on the temperature and pressure (T&P) valve on the side of the hot water tank and let a little water drip out, or turn on a hot water tap inside your home for a few seconds. [4]
    • If you open the T&P valve, put a bucket under it to catch any water that comes out.
  5. Try to determine the general location of the leak—is it coming from on top of the water heater, somewhere along the side, or on the bottom of the tank? [5] Try these tips to determine where the leak is located:
    • Look for areas where the leak may have caused rust or corrosion to appear on the tank.
    • Check the valves, connections, and fittings to see if they’re leaking.
    • Dry the water, then watch to see where new water comes from. Laying down paper towels can help you see where the moisture first appears.
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Section 2 of 6:

What to Do If Water is Leaking from the Top of the Tank

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  1. On top of the water heater, there’s a cold water pipe that brings water into the heater, and a hot water pipe that carries water from the heater to the rest of your home. These pipes can sometimes become loose, allowing water to leak out. Feel around these pipes and their fittings to see if that’s where the water is coming from. [6]
    • How to fix it: If the pipes are the source of the leak, use a wrench to securely tighten the connectors holding the pipes in place on top of the water tank.
  2. Carefully run your fingers all around the seam where the top of the tank meets the body. If you feel water, double-check the pipes—water coming from the fittings may gather along the seam, making it seem like that's where it's coming from. If there’s no water coming from the pipes but there’s water along the seam, the seam is probably leaking. [7]
    • How to fix it: If the seam is leaking, you’ll probably need to replace the tank. Expect to pay around $1,000 to $2,500 for a new, professionally-installed water heater.
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Section 3 of 6:

What to Do If Water is Leaking from the Side of the Tank

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  1. The temperature and pressure (T&P) relief valve looks like a small tap coming out of the side of the water heater tank, with a small lever on the top or side. [8] Check for leaks around the threaded connections where the valve attaches to the tank, as well as the drain pipe leading from the valve. [9]
    • How to fix it: If the T&P valve is leaking, check your water temperature and pressure and test the valve itself.
  2. If the water temperature is set too high, too much pressure could build up inside the heater as the water expands. The T&P valve will then expel some water to relieve that pressure. [10]
    • How to fix it: Find the temperature knob on the side of your hot water heater and adjust the temperature down to 120–125 °F (49–52 °C).
  3. Some homes have a water pressure regulator to lower the pressure of the water coming into the home. If it's too high, the excess pressure can cause leaks around your water heater's T&P valve. Look for this valve near your water meter or main water shutoff and use a gauge to check the pressure. [11]
    • How to fix it: If the valve is set to higher than 50-60 psi, use a wrench to turn the adjustment knob on the valve so it's at the correct pressure. [12]
    • You may also need to add an expansion tank, which will divert excess pressure from building up inside the main tank. To install an expansion tank, turn off the water to the heater, detach the cold water supply pipe, and attach the expansion tank so it sits between the hot water heater and the cold water supply pipe. [13]
  4. Place a bucket under the pipe that comes off of the T&P valve, then lift up the lever on the valve. Once you see a little water coming out of the pipe, let go of the lever so it snaps back down. If no water comes out when you lift the lever, or if water keeps coming out after the lever snaps back down, replace the T&P valve. [14]
    • How to fix it: Call a professional if your T&P valve needs to be replaced. A valve replacement will probably cost around $100.
  5. If you have an electric water heater, check whether water is leaking from the heating element gaskets. [15] If you have a gas water heater, check the gaskets around the gas control near the bottom of the tank. [16]
    • How to fix it: Because leaks in around the heating element or gas control pose an especially high risk of fire, call a professional to replace these gaskets. Expect to pay around $50 for a professional replacement.
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Section 4 of 6:

What to Do If Water is Leaking from the Bottom of the Tank

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  1. Feel around the drain valve to see if water is coming out from around it. Check the threaded connections where the drain meets the tank. Also check the bottom of the drain for drips. [17]
    • How to fix it: If the leak is coming from the drain tap, try tightening the drain with a flathead screwdriver.
    • If closing the drain valve doesn’t stop the leak, replace the valve. Turn off the power and water to the tank and drain the tank completely. Use pliers or a pipe wrench to remove the old drain, wrap the threads of the new valve in PTFE tape and coat them in joint compound , then screw the valve into place and tighten it with a pipe wrench. [18]
  2. If the tank is damaged by corrosion, you might notice rust on the outside of the water heater tank or rusty water coming out of your taps when you turn on the hot water. [19] If the tank is cracked, you might feel water coming out from around the bottom seam of the tank.
    • How to fix it: If your tank is cracked or corroded, you’ll need to have a professional replace the whole water heater. [20]
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Section 5 of 6:

Is a leaking water heater dangerous?

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  1. Any time water leaks near electricity, it can pose a fire hazard. Also, leaking water can lead to mold growth. Call a plumber if you can’t find or repair the source of the leak. [21]
Section 6 of 6:

How to Prevent Water Heater Leaks

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  1. Every few months, visually inspect your water heater to ensure it’s in good working condition. Check the valves, drains, and connections to ensure they’re free of rust or wear and tear. [22]
    • Open the T&P valve once a year to test it. Not only will this ensure it’s working properly, but flushing the T&P valve regularly can help prevent mineral buildup from blocking the valve and causing leaks.
  2. To flush the tank , home improvement specialist Patrick Johns recommends turning off the power or gas to the water heater first. Then, turn off the water and attach a garden hose to the drain valve, then take the other end of the hose outside. Open the valve and let the tank empty completely.
    • When you’re finished, close the valve and refill the tank, then turn on the power or gas and the water. [23]
    • Over time, sediment and minerals can build up inside your water tank. This can cause your water heater to work less efficiently. It can also cause the valves to stick, leading to leaks.
  3. To check your anode rod, turn off the power or gas to the tank, then turn off the water. Open the drain valve and empty a few gallons of water into a large bucket, then use a socket wrench to remove the anode rod. If the anode rod has corroded to less than 1 ⁄ 2  in (1.3 cm) or if it’s covered in calcium deposits, replace it with a new one. [24]
    • The anode rod is usually on top or the side of the water heater—check your owner's manual for the exact location of yours.
    • To replace the anode rod, use a socket wrench to release the old one. Wrap PTFE tape around the threads of the new rod to secure it, then screw it tightly into place. Then, refill the tank and turn the gas or power back on.
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      References

      1. ↑ https://wg.scene7.com/is/content/wrenchgroup/condensation-of-gas-water-heaters-mp21wi001wgpdf?$Wrench_New$
      2. ↑ https://youtu.be/kaxp90o8FFc?t=12
      3. ↑ https://youtu.be/7-cCcYviJqQ?t=10
      4. ↑ https://youtu.be/OSec02MZgAM?t=34
      5. ↑ https://www.thisoldhouse.com/plumbing/21016106/how-to-diagnose-and-repair-a-leaking-water-heater
      6. ↑ https://www.thisoldhouse.com/plumbing/21016106/how-to-diagnose-and-repair-a-leaking-water-heater
      7. ↑ https://youtu.be/7-cCcYviJqQ?t=37
      8. ↑ https://www.thisoldhouse.com/plumbing/21016106/how-to-diagnose-and-repair-a-leaking-water-heater
      9. ↑ https://youtu.be/7-cCcYviJqQ?t=47
      1. ↑ https://www.thisoldhouse.com/plumbing/21016402/how-to-maintain-a-water-heater
      2. ↑ https://www.ladwp.com/construction-services/water-services/water-pressure
      3. ↑ https://youtu.be/eDxx_od_LL0?t=109
      4. ↑ https://youtu.be/P9iQxYQc2J0?t=239
      5. ↑ https://www.thisoldhouse.com/plumbing/21015864/how-and-why-to-maintain-a-temperature-and-pressure-valve
      6. ↑ https://www.thisoldhouse.com/plumbing/21016106/how-to-diagnose-and-repair-a-leaking-water-heater
      7. ↑ https://youtu.be/7-cCcYviJqQ?t=55
      8. ↑ https://youtu.be/7-cCcYviJqQ?t=65
      9. ↑ https://youtu.be/OBPJYg0o_o0?t=55
      10. ↑ https://www.thisoldhouse.com/plumbing/21016106/how-to-diagnose-and-repair-a-leaking-water-heater
      11. ↑ https://youtu.be/7-cCcYviJqQ?t=74
      12. ↑ https://www.thisoldhouse.com/plumbing/21016106/how-to-diagnose-and-repair-a-leaking-water-heater
      13. ↑ https://www.thisoldhouse.com/plumbing/21016106/how-to-diagnose-and-repair-a-leaking-water-heater
      14. ↑ https://www.thisoldhouse.com/plumbing/21124362/how-to-maintain-an-electric-water-heater
      15. ↑ https://www.thisoldhouse.com/plumbing/21124362/how-to-maintain-an-electric-water-heater

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