If your hot water heater is leaking, a leak from the top is by far the best scenario. A leak that is originating from the top of a water heater, if caught in a timely manner, is almost always repairable. However, if not fixed promptly, these types of leaks can lead to serious and costly damage, as water travels down the exterior of your water heater.
If a water heater leaking from the top is left unrepaired, water could enter the electrical component compartment, and cause an electrical short to develop. Another possible problem that could develop is water damage to the floors or walls surrounding your water heater. If you suspect your water heater is leaking, it's important to address the issue as soon as possible.
When Your Water Heater Leaks from the Top
A leak from the top of your water heater is generally a pretty easy fix. Your first step, of course, is to find where the leak is originating. We highly recommend turning OFF the power before you begin working on your water heater.
Once the power is OFF to the water heater, locate the cold water inlet. The cold water inlet allows water to enter the tank to be heated. By leaving the valve ON, a leak will be easier to find.
Dry the top of the water heater where the cold water inlet enters the tank. Then use a paper towel to help you spot the leak if you are unable to see water seeping. Check the pipes and seals for water leakage.
Once you locate the leak, turn the cold water inlet valve OFF (the valve is located on the pipe that leads to the cold water inlet). This should stop the leak and help prevent any further water damage.
Common Causes of a Leaking Water Heater
When it comes to a leak on the top of your water heater, there are three common causes:
Cold Water Inlet Valve
First, check the cold water inlet pipe. Look for a ball valve or gate valve that'll allow you to turn the water off. A ball valve has a lever to turn the water on and off. When the lever is parallel with the pipe, the valve is open which will allow the cold water to enter the tank.
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Check the valve for leakage. If you notice that it's dripping, the solution may be as simple as tightening the nut that connects the handle. However, if after tightening the nut and it's still leaking, the valve is most likely faulty and will need to be replaced.
Loose/Corroded Pipe Fittings
Check the water inlet and outlet fittings (also known as dielectric nipples) to see if there's any water leaking. Look closely at the point where the pipe connects to the dielectric nipples and any other fittings.
If you find that your leak is coming from one of the connection points, try tightening the pipe with a wrench. The problem could simply be a loose connection.
These nipples often become corroded. If this is the case, you may need to replace the fitting itself. However, it's also possible that it's a more serious issue with the tank itself. If the tank is beginning to rust, you'll need to buy a new water heater.
If you need to replace the dielectric nipples, it's typically not a difficult task. Although, they can sometimes be difficult to remove from the tank.
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Some water heaters were installed with copper tubing instead of threaded pipe. Unless you are comfortable working with copper, we recommend hiring a qualified plumber to make the repairs for you.
Temperature & Pressure Relief Valve
The temperature and pressure relief valve (T&P valve) is either located on the side of the tank or on the top. Inspect the valve location closely. If you notice water seaping out from the valve's threads you'll need to remove it in order to determine if it's the issue.
As a general rule, if this is the problem, your best bet is to replace the T&P valve with a new one. These valves are installed for safety and you want to make sure that it's in good repair.
Temperature Pressure & Relief Valve
Follow these steps to change your T&P valve:
- Drain the tank until the water level is below the valve. (Click here to learn how to drain your water heater).
- Open a nearby hot water tap to let air into the tank.
- Use a pair of channel locks to unscrew the valve from the tank.
- Check for rust or corrosion on the tank by inspecting the hole where the valve had been located. If you find any rust or corrosion, your water heater will need to be replaced.
- If there's no visible rust or corrosion, wrap the threads of the valve in Teflon tape, which will help seal the valve. Then screw the T&P valve back into the tank.
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After performing any repairs to your water heater, it is important to closely watch to see if the problem persists. If the leaking continues, you should call a professional plumber.
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Other Issues that Could Cause Your Water Heater to Leak from the Top
If you own a gas water heater, it's possible that rain water has travelled down the flue vent pipe and collected on the top of your tank. This could happen during stormy weather, especially if there are high winds.
Another cause could be condensation. It's normal to see a small amount of condensation on the exterior of a water heater. However, if your heater isn't able to meet your household hot water demand, you may notice more condensation than normal. This happens because the moisture isn't allowed to dissipate since the tank is too small to meet the demand for hot water.
The articles below can help you continue troubleshooting or determine your next steps:
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