Why Is My Water Heater Leaking From Overflow Pipe?

Ossiana Tepfenhart
by Ossiana Tepfenhart

It is a bad sign when any appliance leaks water, especially if it’s your water heater. Water heaters are typically low-maintenance, but it’s important to address problems right away. So, why is my water heater leaking from the overflow pipe?

Loose pipe joints can cause your water heater to leak from the overflow pipe. Your temperature-pressure relief valve can get stuck in the open or shut position and cause your overflow pipe to leak. Replace your water heater overflow pipe if you find signs of rust or corrosion.

Always remember to shut off the water supply and power to your water heater when you repair it. Follow along as we explore why your water heater is leaking from the overflow pipe.

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Why Is My Water Heater Leaking From Overflow Pipe?

A leaking overflow pipe doesn’t typically indicate that your water heater is broken. However, it does tell you that there is a problem with your water heater that is causing it to leak. It is best to diagnose and fix the problem right away so it doesn’t get worse.

Loose Joints

Loose joints in your water heater can cause water to leak from the overflow pipe. Luckily, you can easily fix it with a wrench and some plumber’s putty. Inspect the pipes in your water heater and look for a loose joint.

Shut off the water supply and power to your water heater. Open up the pipe joint and clean the threading with a fine tool. Apply plumber’s putty and reattach the joint so that it fits tightly and won’t leak. Turn your water heater back on and see if water still leaks from the overflow pipe.

Defective TPR Valve

A temperature-pressure relief valve, or TPR valve, is a critical component of any water heater. Your TPR valve can get stuck in the closed position, and this can cause your water heater to leak from the overflow pipe. An open TPR valve can also cause a leak because it creates excess pressure in the water heater.

High-temperature water can lead to an increase in pressure for your water heater. This can make the water overflow and leak out of the overflow pipe. Repair or replace your TPR valve to decrease the pressure in your water heater so it doesn’t leak. Lower the temperature on your water heater so you don’t overload the TPR valve if it continues leaking.

Corroded Overflow Pipe

Water heater overflow pipes are prone to corrosion because of the moisture and temperature. This is especially true if your water heater is in a cramped space with poor ventilation. Inspect the overflow and look for signs of excessive rust and corrosion.

Unfortunately, you cannot repair an overflow pipe that is too corroded and you must replace it. It costs an average of $220 to replace the overflow pipe on a water heater, but it can cost more depending on your unit.

Prevent Water Heater Overflow Pipe From Leaking

The best way to prevent your water heater overflow pipe from leaking is to lower the temperature. Never turn your water heater temperature higher than 120 degrees Fahrenheit. High temperatures can increase the pressure in your water heater and cause water to leak from the overflow pipe.

Extreme heat can cause water to expand within the pipes and overload your water heater. Replace your TPR valve every 3 years so that it stays in good shape and prevents leaks. Flush your water heater every 6 months to keep it in good condition.

Cost to Fix Leaking Overflow Pipe

Like with many plumbing issues, getting a water heater leak fixed can have a wider range of prices. The price of a DIY fix depends on what parts you need in order to repair the fix. Parts can run between $20 and $200 or more, depending on what you’re buying. We do not suggest complicated DIY water heater fixes due to the danger that a bad water heater can pose.

If you are unable to fix it on your own, then you will need to call a plumber. Typical water heater leak repairs will cost between $200 and $250. If it’s the pipe that needs to be fixed, you might have a slightly lower cost. The good news is that most water heaters that have this leak are going to be repairable by most peoples’ standards.

How to Replace Overflow Pipe

If you do have the skills to fix it on your own, here’s what you can do.

  • Turn off the gas, flip the breaker, or both, depending on your water heater. You want to make sure to make things safe. Close the cold water cut-off valve going into the water heater.
  • Next, open the overflow to drain the water out of the tank and relieve pressure. Let it drain for about 60 seconds before removing the overflow pipe from the valve. If the valve is soldered or glued into place, you may need to cut it off using a small hacksaw.
  • Unscrew the old valve using a pipe wrench, and replace it with the new valve. Screw the new valve on until tight, then apply Teflon tape to the threads. Reattach the valve drain pipe, and open the cold water cut-off valve.
  • Check for any leaks around the overflow pipe. 

Drain Pan

Make sure to install a drain pan under your water heater. For the future, consider getting a water heater drain pan installed underneath your water heater (if you don’t already have one). Of course, this won’t stop all the damage if you have a major leak and you’re not home. However, it can certainly save you some trouble if you catch the leak early.

A drain pan should be at least 2 inches wider than your water heater in diameter and costs between $85 and $100 to install. You can purchase 4-inch pans to contain a larger leak.

What Should I Do If The Water Heater Leak Turns Into A Downpour?

Extreme leaks that could be classified as heavy breaks need to be addressed immediately. The first thing you should do is put on some protective gear. Then, go to the heater and shut off both the water and the temperature.

Do not attempt to fix the leak yourself. Rather, focus on cleanup.

Once that’s done, grab a cellphone and take photos of any damage that has been done for insurance purposes. Most homeowner insurance policies will be willing to cover at least some of the damage.

After you take the photos, call up a plumber and your insurance company. They will be able to guide you through the next steps and also fix your pipe.

Do You Need Water Heater Repair Services?

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Related Questions

What brand of water heater is the best and how long do they last?

There are many water heater brands that are considered to be top tier by consumers. These include Navien, Rinnai, Stiebel Eltron, as well as more mainstream names like Ecosmart.Though there is a little bit of variation when it comes to water heater life expectancy, you can expect a typical heater to last 8 to 12 years. Some, with careful maintenance, can last as long as 20. To get a better idea of your water heater’s life expectancy, check the warranty that came with it.

Can I get money for recycling my old water heater?

Most recycling centers will offer you a nominal fee for your water heater, based on the amount of aluminum, copper, and steel that your heater has. This won’t be much, but it still will be some money for the troubles that you had to go through to get the heater to the plant.

Is a leaking water heater dangerous?

When you have a leak in your water heater it can cost you money in repairs, inconvenience you, and may cause significant damage. These leaks should be taken seriously, as, unlike more common plumbing issues, it has the potential to be dangerous or even deadly.If your water heater’s TPR malfunctions or your water’s temperature gets set too high, there is a chance you could have your heater explode. However, most water heaters will never come even remotely close to having this happen. It’s an exception to the rule.

Ossiana Tepfenhart
Ossiana Tepfenhart

Ossiana Tepfenhart is an expert writer, focusing on interior design and general home tips. Writing is her life, and it's what she does best. Her interests include art and real estate investments.

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