Many water heater leaking problems can be DIY repair projects. However, knowing what is causing a leaking water heater can be a challenge.
I’ll walk you through finding the leak, and how to actually repair the water heater. However, sometimes it’s just better (or required) to get a new water heater.
Relax, I’ll tell you how to know the difference between a repair and a replacement.
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Table of Contents
Consequences Of The Water Heater Leaking
Although it may look like a minor annoyance when your hot water heater is leaking, it can turn into a huge problem very quickly. Even small amounts of water will damage your walls, sub-floors, and floors.
A hot water heater leaking could also be a symptom of a much bigger problem. In extreme scenarios, a complete and catastrophic water heater failure may result in substantial flooding that could lead to damaged personal property, resulting in hefty repair bills.
A leaking water heater can also cause minor, or even serious, health problems. Areas that are constantly wet or damp can develop mildew and mold. That may result in some people experiencing asthma and allergic reactions.
According to EPA warnings, various types of mold spores are toxic and could lead to serious health problems.
How to Find The Real Cause Of A Leaking Water Heater
A hot water heater leaking problem won’t simply disappear on its own. The problem will only get worse the longer you wait. Your best course of action is to move fast to first determine the cause and then to fix the problem.
The problem is often not as serious as what it may appear at first glance. In these cases, the cause can be fixed easily. However, you first need to find it. The steps below will help you diagnose and repair your leaking water heater.
Determine the Source of the Leak
Not all little puddles of water you may find around your water heater are due to leaks. Condensation may form on the appliances and pipes close to your water heater. As this condensation accumulates, it often drips and ends up on the floor. This is very common during damp weather and in basements.
It might not be the water heater leaking, but some other part of the plumbing system. Including water softener discharge lines and boiler or furnace drain lines could have leaks. If you see a little puddle of water close to or under your water heater, follow the steps below to figure it all out:
- Dry the water and inspect the plumbing fittings and water heater for noticeable signs of water leaking to determine the cause.
- If you don’t find anything, check other nearby possible sources. As water will follow gravity laws, inspect anything directly above where you found the water, especially water pipes.
- If that doesn’t turn up any obvious culprits, dry the floor and place some paper towels where the puddle was. Check these every few hours for signs of water.
- If the problem doesn’t re-appear after a day or two, it’s likely not something to be concerned about.
- If the water does however reappear, and you can find no other source, the problem is probably with the water heater.
Turn Off the Gas and/or Power
Once you have figured out that it is your hot water heater leaking, the first step you need to take is to turn the power supply off.
If your water heater is electric, locate the circuit breaker box and switch the water heater’s breaker off. Electricity and water is a dangerous, even lethal combination, so it’s important to do this before doing anything else.
If you have a gas water heater, these normally have an on/off dial or switch on the exterior of the tank close to the bottom. Make sure this is set to the OFF position.
If possible, don’t close the gas shut-off valve as those valves are often finicky and vulnerable to failure over time. It’s therefore best to leave them alone.
Note: Hot water heaters are normally factory-set to heat water to 125°F. This is hot enough to cause first degree burns on skin. When the temperature is set to the maximum, which can be anywhere between 160°F and 190°F, even indirect contact with the water can cause serious injuries. Always make sure you avoid contact with hot water.
Turn off the Water Supply
If the leak is major and obvious, turn the water supply off at the cold water shut-off valve.
With most hot water heaters, the valve to shut off the water supply is located above the water heater.
The cold water shut-off valve will either have a gate valve that can be turned clockwise, or a handle to pull down to close the valve.
Note: If you can’t reach the valve safely without coming in contact with hot water, stay safe and don’t close it.
If the leak is major and you are not able to close the incoming cold water shut-off valve due to safety concerns, find the main shut-off valve to your home and close that.
Closing the main shut-off valve will prevent any water from flowing into your house. Which will also shut off the water supply going to the water heater.
Closing just the water supply valve will at a minimum slow the leak down. However, it may even stop the leak completely, depending on where it is.
However, you need to understand that you may have to turn the water supply back on to help find the leak if you’re still not sure of where exactly it is.
Find the Leak’s Location
There are several common causes of water heater leaking problems. Finding the real cause can be determined by some simple observations. Then you can decide to do the work yourself or to contact a local plumber. Let’s look at some of the most common areas prone to leaking:
Hot Water Outlet Connection and Cold Water Inlet
Check the connections of the outlet and inlet pipes to the water heater. These are often at the top of the unit, but some units use side connections. If the leak is located at these connections, fixing it may be as simple as tightening all loose connections.
Is the Water Heater Leaking From The Drain Valve?
The drain valve is located at the bottom of the tank. Ensure that it is completely closed and check where it enters the tank. This should be completely shut off. With no dripping or other signs of water. A leaking drain valve is not serious and can be fixed easily.
Temperature and Pressure Relief Valve
All hot water heaters have a temperature and pressure (T & P) relief valve situated on the top or side of the tank. This valve should have a pipe attached that goes down to the ground.
The T & P Valve is a safety device whose function is to relieve excess pressure when the water in the tank is too hot, or when extreme pressure in the tank may cause it to burst.
In those cases, the T & P valve will open and allow some of the water out of the tank, thereby relieving the tank’s pressure.
Check for signs of a leak at the entry point of the T & P valve into the tank and then inspect the actual valve.
- If the valve is actually open, it’s probably releasing the excessive pressure that is forcing the valve open. If that is what is happening, the leak can generally be fixed. However, the situation is probably serious enough to contact a local plumber to fix the problem.
- If the T & P Valve is closed and water flows from the pipe, the valve is defective and needs to be replaced.
Internal Water Heater Tank
A water heater’s internal tank is covered in insulation and then enclosed by an outer skin. Internal tank leaks are not visible from the outside and water will eventually run from the bottom of the outer skin.
It is unfortunately common for internal tanks to start leaking, normally due to deterioration and age. If an internal tank starts leaking, the only resolution is to buy a new water heater.
Replace or Repair
As discussed above, water heater leaks can cause serious problems and action has to be taken as fast as possible. You will either have to replace or repair your water heater depending on the type and the severity of the leak. In either case, we highly recommended that an experienced plumber be contacted.
When you contact a local plumber they’ll be experienced and will be able to handle any problems they encounter. In most cases, they’ll even dispose of your old water heater for you. If you’re in a situation where you need to replace your water heater, you may want to investigate changing to a tankless system .
How to Fix a Leaking Water Heater
If you have some experience with doing home plumbing repairs and the problem seems to be simple, you may decide that you’ll fix your water heater yourself. If this is the case, the next steps you need to take will depend on the leak’s source.
Note: Repairing a water heater can be tricky. Repairing a water heater incorrectly can cause bigger leaks, or even floods which may in turn lead to more serious problems. If you aren’t experienced in performing home plumbing repairs, we highly recommend that you contact a local plumber rather than trying to fix it yourself.
Leaks at Cold Water Inlets or Hot Water Outlets
Leaks at hot water outlet or cold water inlet connections, from or to water heater, can often be easily fixed. Simply by tightening any loose connections with a pipe wrench. Or by replacing the rubber washer inside of the connections. However, if this does not solve the problem, it is best to contact a local plumber.
Take a look at this video:
Water Heater Leaking At The Drain Valve
Generally, drain valve leaks are the result of just a couple of things. It could be caused by the valve itself being faulty, or by debris inside the valve.
Place a container under the drain valve and turn the handle anti-clockwise to open the valve. Water flowing out of the tank will tend to flush out any debris. That is, unless you haven’t flushed the tank regularly.
In which case, you may have other problems that changing the drain valve won’t fix. So, if the valve is still leaking after the tank has been flushed, and the drain valve cleaned out, then what?
Well. the valve needs to be replaced. So, remove it and check the tank for corrosion where the valve came out. If you see any corrosion, replace the water heater. At this point, replacing the drain valve might not fix the leak. If it does fix the leak, it will only be short lived.
To replace the drain valve, the tank needs to be drained completely. To drain the tank, follow the same steps described in the next section for replacing the T & P valve.
Note: The drain valve is provided for convenience during maintenance. So, it’s not a safety feature. Whereas, the T & P valve IS for your safety.
If this sounds like a bigger job than you want to do yourself, here’s what to do.
Purchase a brass garden hose end cap and just screw it onto the drain valve’s threads. This will stop the leak until the drain valve can be fixed or replaced.
Watch this video explanation of how to replace a water heater drain valve:
Leaks at the Temperature and Pressure Relief Valve
A leak from the temperature and pressure relief (T & P) valve may be caused by excessive pressure or overheating inside the tank. When the tank is under too much pressure, the valve will open, allowing water to escape, and thereby relieving the pressure.
To check if this is the cause of the problem, lower the thermostat setting to reduce the tank’s temperature. Turn the water and gas or power to your heater back on and check the valve. If it is still leaking even at the lower temperature, shut everything off again and call a professional.
If you have determined that the problem is not caused by overheating or excessive pressure, the T & P valve may be faulty. Place a container under the T & P’s discharge pipe and open the valve by pulling its tab up to point straight out.
This will result in flushing the valve and removing any debris that may cause it to work incorrectly. If it is still leaking after flushing, you’ll have to replace the valve with a new one.
Note: The temperature and pressure relief valve should never be plugged to stop a water leak. That’s because it’s a critically important safety feature of your water heater. Not only will plugging the valve void the warranty on your water heater, but it may in fact cause the water heater to explode!
- CASH ACME RELIEF VALVE: Cash Acme NCLX Combination Temperature and Pressure Relief Valves are designed for the protection of water heaters and storage tanks; incorporate an inert thermal element coating that provides effective isolation from mineral deposits (liming) and galvanic corrosion
- DESIGN: The NCLX Series relief valves feature a cast bronze body, brass, and stainless steel internal parts, silicone seat disc, and stainless steel pressure spring
- COMPACT: Pressure-reducing and regulating valves
- SPECS: NCLX Valves come with standard factory settings of 150 PSI for pressure relief and 210 degrees F for temperature relief
- CERTIFIED: The NCLX Temperature and Pressure Relief Valve is certified to be lead-free in accordance with NSF 319; compliant with ASSE standard 1003 and CSA standard B358
Replacing the T & P Valve
Before replacing the T & P valve, the hot water tank needs to be drained.
Note: The tank does not need to be emptied completely, but the water level must be below the valve. This is easily checked by opening the valve. The water level is below the valve if no water comes out with the valve open.
Replace the T & P Valve by following these steps:
- After draining the tank, open a hot water faucet on a bathtub or sink to allow air into the tank.
- Grab the T & P Valve with a pair of channel locks or pipe wrench, and turn it counter-clockwise until the valve separates from the tank.
- Use Teflon tape to wrap the threads of a new T & P Valve to help seal the connection and prevent future leaking. Ensure that the Teflon tape is wrapped tightly and work it into the thread grooves. About 4 or 5 wraps should be sufficient.
- Using a pair of channel locks again, screw the new T & P Valve into the water heater.
- Allow the tank to fill with water by turning the cold water back on.
- Note: Don’t turn the heater’s power back on before the tank is full.
- Once water starts to flow at a full stream from an open bathtub or sink’s hot faucet, the tank is full and it is safe to turn the water heater’s power on.
- Attach the discharge pipe to the T & P Valve to ensure that any hot water released by the valve will run onto the floor, rather than spraying outward.
Watch this video on how to replace a T&P water heater valve:
Other Leaks on T & P Valves
If there is water is leaking from a T & P valve’s threads, this may indicate a bigger problem. Follow the steps above to remove the valve and check for signs of corrosion or rust on the tank.
The water heater needs to be replaced if there is any corrosion or rust. If the tank seems to be in good condition, wrap the T & P valve’s threads in Teflon tape before screwing it back into the tank. Check your water heater for a while to see if the problem has been solved.
Another cause of the T & P valve leaking could be high water pressure in the city water system. Or some type of backflow preventer around the main shutoff or water meter. If there is no sign of corrosion inside the T & P valve, this could possibly be the problem. These more serious leaking water heater problems should be diagnosed and fixed by a licensed plumber.
Water Heater Leaking From The Internal Tank?
If a water heater leaks from the bottom of the tank it is likely that there is a serious internal problem. Don’t try to take the water heater apart to fix it internally.
A water heater leaking from the inside can’t be repaired and the water heater needs to be replaced. However, if you are still wondering what needs to be done, contact a local plumber to check out your water heater.
What to Do When Repairs Don’t Fix a Leaking Water Heater
As a leaking water heater can indicate that there are more serious underlying problems, it’s always important to keep checking the heater after any repairs have been performed.
So, what do I do if I made repairs and I still have a leaking water heater? First, turn off the cold water supply and the power. Second, watch the video below to see if there is something else you can do yourself. Third, if you still need help, contact a local plumber
Still wondering what to do? Watch this video:
Last update on 2023-12-03 / Affiliate links / Images from Amazon Product Advertising API