Causes for Hot Water Heaters to Leak Into the Overflow

Brad Stewart

People tend to take the creature comfort of a hot water heater for granted. But the machine that affords us such luxuries can occasionally be susceptible to major problems. If you should find an alarming leak in your hot water heater, there are a myriad of possible culprits to check for.

A working hot water heater is essential to modern living.


It’s a possibility that the buildup of moisture on your water heater isn’t a leak at all. If you notice the “leak” when the weather, and by extension the water coming into your boiler, is particularly cold, then it’s entirely possible that what you’re experiencing is the buildup of condensation. This should completely disappear when the boiler is powered on and heats up.

Drain Valve

The drain valve is the spigot-like mechanism located at the base of your water heater. Water will leak from any drain valve that is not properly tightened. This cause is straightforward to fix, as it simply involves tightening the drain valve with a wrench.


Check the pipes in close proximity to your water heater. If the pipes are too loose or weren’t properly fitted together then leaks will crop up. These need to be refitted either by you or a professional.


While hot water heaters are built for durability and reliability, some older models will be vulnerable to corrosion. The corrosion will cause weak spots and small holes in the metal, and leaks will manifest.


If your water heater is gas-powered then it will have a vent on top. This vent needs to be cleaned regularly or it can become clogged. When this happens, water can build up and overflow.

Temperature Pressure Valve

The temperature pressure valve is located on top of your water heater. It’s designed to release water when the heater becomes dangerously overheated. It will become overactive if the water temperature level is set excessively high or if the pressure in the water is too great.