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How To Fix A Leaking Water Heater

leaking water heater
Fix January 17, 2020
Arthur Brodskiy
Arthur Brodskiy


Few things can strike fear into the heart of a homeowner like a leaking water heater. Those tanks hold a lot of water, and images of ruptures, tank explosions, and expensive water damage come to mind when we think of water heater leaks. If you do have a water leak, it’s possible that the cause is a small problem with an easy fix. Let’s go over the different reasons water heaters can leak and what you can do about it.  


Is A Leaking Water Heater Dangerous?


Leaking water heaters can be dangerous to homes and the people who live in them. Leaking water can cause expensive damage to the floor and subfloor of your home. Leave it alone long enough and standing water can eventually cause mold and mildew to develop, leading to potential health hazards and even more expensive cleanup. Not only that, leaking water heaters can literally be a ticking time bomb.


Water Heater Explosions


A leak could also mean your water heater is at risk of catastrophic failure. High pressure combined with a faulty pressure release valve could lead to a sudden tank rupture or explosion. A tank explosion poses an immediate safety risk and can cause instantaneous water damage to the surrounding area. 


Turn Off The Water, Power And Gas Supply


Before you do any work or maintenance on your water heater, it’s important to shut off the water, power and gas supply going to the unit. If you have a sudden, substantial leak, turning off the water supply can help prevent serious water damage. 


Determine The Source Of The Leak


drain valve leaking


Loose Inlet / Outlet Connections


  • The top of your water heater should have two pipes running from it. One is the inlet line, which lets cold water in from your water main. The other is the outlet line, which takes the heated water from your water tank and delivers it to the rest of your home. 
  • There could be a loose connection on one or both of these lines. If they seem loose, tightening them with a pipe wrench could solve your problem right away. 


Loose Drain Valve


  • Your drain valve can be leaking for a couple of reasons. It could be that the valve is just loose. It could also need a new washer. 
  • The drain valve is located near the bottom of the tank and looks similar to a hose bib. If the drain valve is slightly open, it could be leaking water onto the floor. If the valve is completely closed but still leaking, you might have to replace a washer or the valve entirely. 


Cracked Water Tank


  • Sometimes the leak is coming from the tank itself. Water tanks are designed to last around 10 years. Over time, corrosion from hard water and sediment will start to degrade the lining of the tank, leading to cracks in the tank’s surface. Once a water heater has gotten to this point, the only fix is to replace the entire unit.
  • If you notice water pooling around the bottom of the tank and you’re certain the pressure release valve isn’t the cause, you could have tiny cracks or holes in your water tank. If you suspect the tank is leaking, arrange to have a professional plumber over as soon as you can.  


High Pressure Issues


  • Your water heater should have a pressure release valve close to the bottom of the tank. The valve is designed to protect the tank from expanding water as the temperature increases. Excess water is released from the valve, reducing the pressure inside the tank. 
  • If you notice a substantial amount of water coming from the release valve, check the temperature gauge on your water heater. It should be right around 140 degrees. If it’s any higher, reduce the temperature. 
  • If the temperature is normal, it could mean that the valve is defective. Have a professional plumber install a new pressure release valve on your water heater. 
  • You can also check the water pressure in your home by using a pressure gauge. Attach the gauge to any hose bib in your home and look at the reading. 40-45 psi is a good standard range for most homes. Anything over 75 and you’re getting into dangerous, high-pressure territory. 




If your water heater is leaking, fixing it as soon as possible is definitely a top priority. But what if your water heater seems totally fine? Doing a little legwork now can help you avoid leaks in the future, saving you time and money in the long run. Two important things for maintaining a healthy water heater are preventive maintenance and monitoring


Draining Your Water Heater And Other Maintenance


Unfortunately, owning a water heater means you’ll have to do some regular upkeep. Yes, you’ll have to drain your water heater from time to time. Sticking to a maintenance schedule can help you make sure you don’t run into any surprise leaks in the future:


Drain and flush the tank once every year. Minerals get sifted out of the water in your water heater’s tank every time it gets heated up. After a while, these minerals start to collect at the bottom of the tank as sediment. Flushing your water tank annually will remove this sediment before it builds up to the point that it starts causing problems.


Vacation mode. If you plan on leaving town for an extended amount of time, you don’t need your water heater doing extra work. Putting it on vacation mode will stop it from running the heating cycle while you’re gone. It can help extend the life of your water heater, and lower your utility bill. 


Test the pressure release valve every year. The pressure release valve is a safety device that lets excess water out of your water heater tank if the pressure gets too high. Sometimes, these valves can fail without us realizing it. Open the valve, let a little water out, and check around the seal for signs of leaking. 


Check up on your expansion tank. One of the ways modern water heaters deal with changes in pressure and temperature is with thermal expansion tanks. When water starts to heat up, it expands. This extra volume needs somewhere to go, which is often your thermal expansion tank. If the tank is covered in condensation or makes a dull “thud” sound when you tap it, it either needs to be repaired or replaced. 


Keeping Tabs on Leaks and Pressure


A good, consistent pressure range is key to a healthy plumbing system. You can stay on top of your home’s water pressure and catch leaks early by using a smart plumbing device. The Flo by Moen Smart Water Shutoff monitors your plumbing network constantly, keeping tabs on pressure, flow and temperature.  Leaks of all sizes, as big as a burst pipe, to as small as a drop per minute, will be detected. In fact ,in the event of a catastrophic water event, the Smart Water Shutoff will automatically turn off your home’s water in order to prevent damage.




A leaking water heater doesn’t always mean your tank is about to explode. Leaks are often just caused by loose fittings and smaller components that need to be replaced. However, any leak in your water heater system, no matter how small, should be isolated and addressed as soon as possible.

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