Informational Guide

Water Heater Leaking (Common Causes & How To Fix)

by Andrew

Water heaters are an essential appliance that gives you access to hot water for cleaning and showering. Unfortunately, from time to time, you will encounter problems, and a common issue is water leaking from the unit itself.  

This guide will help explain why the water heater is leaking and what you can do to fix it quickly.  

1. Condensation 

Condensation is one of the most harmless reasons that there's a leak from your water heater. Often water heaters are stored out of the way in basements or garages with less insulation.

This means they're in cold environments and working to heat the water. As your water heater becomes hotter, it can cause the cold, damp air to condense and water to form on the outside of your water heater.   

2. Tank Is Old 

Water tanks aren't designed to last forever, and after about 15 years, you will start to encounter more problems. This can be because of old, faulty parts, or it can be due to rust and corrosion damage within the water heater.

You'll find that the water heater will probably start to become less effective as the leaks spring up, and often the solution is replacing the whole unit.  

old tank leaking

3. Too Much Pressure 

Water heaters have to deal with the pressure that comes from heating water. This conversion to steam with no escape route can put a serious strain on your water heater and lead to internal damage. Eventually, this will lead to cracks which cause leaks.

Pressure becomes a problem when the temperature is set too high, when the pressure of the water going into the tank is too high, or when you have a faulty pressure valve.  

4. Inlet & Outlet Connections 

Your inlet and outlet connections control the flow of water in and out of your water heater. These connections will see a lot of water flow through, and over time the connections will become less secure.

If the connections loosen too much, you’ll start to see leaking from your water heater.  

5. Sediment Collection 

A trace amount of sediment flows into your water heater in the water supply. Over time, this sediment can collect in the bottom of your water heater and become a real issue.

If you aren’t regularly flushing and emptying your tank, this sediment will clog the mechanism and even cause cracking. This will cause leaks and may mean you need to replace the whole unit.  

6. Cracked Storage Tank 

Many water heaters have an additional storage tank, so you have access to more hot water if needed. Over time, minerals can gather in these storage tanks and cause damage.

This can often mean your storage tank becomes cracked and it starts to leak. In most cases, you’ll have to replace the whole storage tank if it’s cracked.  

7. Bad Water Heater Anode Rod 

Your anode rod helps prevent rust and corrosion in your machine by drawing the corrosion upon itself. These rods don't last forever, and if it's been in the water heater for more than 2-3 years, it's likely gone bad.

If you fail to replace the anode rod when needed, then the whole water heater can become corroded and cause leaks from any part of the unit.  

Common Parts Of A Water Heater That Leak (+ How To Fix Them) 

Leaks At The Bottom / Bottom Element 

Your water heater typically has a top section which is the primary hot water supply, and an extra section at the bottom for when you need to draw on extra hot water. It's usually easy to notice if there's a leak in the bottom compartment, and you'll visibly see water dripping. If there is an issue, it's usually a quick fix you can sort yourself, or a big issue you’ll need help with.  

How To Fix:

The leak is typically caused by a leaking drain line or a crack in the unit itself. Start by checking the drain lines around the bottom and see if they're loose. Most of the time, these just need to be tightened, and you can do that with a wrench. If there is a crack in the bottom section, then it will need to be replaced. This is expensive, and you'll likely need to call in professional help to do it properly.  

Leaks From Top Top Element Panel 

Again, leaks in the top compartment are usually easy to spot, and it's generally caused by loose inlet and outlet valves.

How To Fix:

Check each connection and use a wrench to tighten them as much as possible. In some cases, you may need to replace the valve because of damage, but you can pick up replacements from any hardware store.  

It’s very unlikely that you’ll get a crack in the top compartment, but it can happen from time to time. If it is cracked, then you won't be able to repair it, and your only option is to replace the whole water heater.  

Leaks From The Seam 

Leaks from the seams are common and indicate that some part of your water heater is damaged.

How To Fix:

You’ll need to open it up and check each section to diagnose the problem. Often, if water is coming from the seams, then it’s a sign that the leak has been there for a long time, and it means it will have caused significant damage. In other cases, you may just need to tighten the connections to stop the leak. If you notice a serious leak from the seam, you should call a professional because it could be challenging to repair.  

Leaks From The Side Panel 

A leak from the side of your water heater generally means there's an issue with the seal around the heating element.

How To Fix:

To check this, you'll need to open up the access panel, remove the insulation, and look for any signs of visible damage or rust. If there is, you'll need to replace the seal, and the only way to do this is by carefully removing the heating element to put a new seal in place. Make sure that the power is completely turned off and the tank drained so you can do this safely.  

Leaks From Flex Hose 

Your flex hose helps water to flow into the heater, but it can develop a leak. This is generally because of a loose connection, and tightening these should solve the issue.

How To Fix:

If it continues, then there may be some damage to the hose, and it will need to be replaced. This is pretty straightforward, and you can pick up a replacement from most hardware stores.  

Leaks From The Overflow Pipe 

Your overflow pipe connects your water heater to the exterior of your home and allows excess water to drain safely when the water level becomes too high. It's normal for it to drip when the water heater is warming up, but if you see a continuous leak, it's a sign something is wrong. Usually, this is caused by a faulty water flow switch within the tank. If this is stuck in the ON position, it means water will continuously be drawn into the heater, and this can damage the machine.

How To Fix:

Remove any visible blockages and readjust the float switch. If this doesn’t work, you may need to replace the float switch entirely.  

Leaks From Pressure Relief Valve 

Your water heater pressure relief valve is designed to stop too much pressure from building up in the system and regulate the temperature. Your relief valve can start leaking if the thermostat is set too high, and this is a common problem with RV water heaters.

How To Fix:

Start by checking your thermostat to ensure it's set at the right temperature. Most water heaters should be set to 140 degrees Fahrenheit though you can typically adjust this by 10/20 degrees without issue.  

If the problem is still there, you should check the water pressure using a pressure gauge. Your PSI should be below 80, and if it's over 100, you'll need to install a pressure-reducing valve.  

If your water pressure is fine and the leak persists, it probably means you have a faulty valve that will need to be replaced.  

Leaking From Top Anode 

Your anode is located in the top part of the water heater and prevents it from becoming corroded.

How To Fix:

To do this, it sacrifices itself and draws all the corrosion towards it, away from the tank. Unfortunately, over time it can become overly corroded and stop working. If you notice water bubbling around the anode, it means that your anode needs to be replaced. It’s also worth getting a professional to check the whole system in case the corrosion has spread.  

water leak

How To Prevent Water Heater From Leaking (Future Proofing Tips) 

Water heaters are expensive to replace, and, in some cases, when you spot a leak, it's already too late. To help protect your hot water supply, there are a few preventative measures to stop leaks from happening in the first place:  

Check Your Water Heater 

It’s beneficial to get into the habit of checking your water heater every 6 months to see if there are any issues. You should look for any rust, corrosion, or other damage which may impact the mechanism. Take this opportunity to clean the interior of the water heater and tighten all the connections. This will save you a lot of time down the road.  

Replace Your Anode 

Your anode plays a vital role in protecting your water heater, and without it, rust and corrosion can quickly spread throughout the appliance.

Check your anode every 6-12 months and replace it if it starts to look really damaged. Always replace your anode every 2-3 years to prevent your water heater from becoming damaged and leaking.  

Flush The Tank 

Flushing your water heater is easy to do, and performing it annually will help improve the longevity of your machine. Rheem water heaters should be flushed at least once a year, and it's easy to do using just the drain valve. Other water heaters may vary, so it's worth checking the user manual. 

home bradford water heater


Can I still use water heater if it is leaking?  

Technically, yes, but you really shouldn't. Continuing to use a leaky water heater can result in more damage to the device and your home, which is expensive to fix. Turning it off and finding the problem is the best thing to do.  

How much does it cost to repair a leaking water heater? 

It will typically cost anywhere from $200-$1,000 to have a professional fix a leaking water heater, depending on the exact problem which needs to be resolved. Some quick fixes, like tightening the connection, can be done yourself and won't cost you anything.  

How long will a water heater last once it starts leaking? 

It's difficult to say because it depends on the exact problem, but once you notice it leaking, it could be a sign of something serious and that it won't last long.  

Is a leaking water heater dangerous?  

Yes, if your water heater is leaking, it can be hazardous in your home. In very, very extreme circumstances, the build-up of pressure can cause it to explode, but it can also cause flooding, scalding from unregulated water temperatures, and can be a fire hazard. There's also a risk of a gas leak with gas-powered water heaters.  


A leaky water heater can be a serious problem, and you need to deal with it right away. If you catch it early enough, you can typically resolve the issue and save yourself a lot of money having to replace it. Hopefully, this guide has helped explain the most common problems facing homeowners with water heaters and has given you some advice on fixing them.