What Causes a Leaking Water Heater?

A leaking water heater is more than a minor inconvenience—it often signals a larger issue. Leaks shouldn't drip or puddle; they shouldn't be ignored. Knowing the cause can help you act quickly and prevent costly damage.

1. Age and Corrosion
Aging is a leading cause of leaking water heaters. Most units last 8–12 years, and internal corrosion can create cracks or holes. If your heater is over ten years old and leaking, it may be time for a replacement.

2. Loose Drain Valve
You'll find a drain valve at the bottom of your water heater tank—a key component for flushing out sediment buildup. If this valve becomes loose or faulty, water can leak from it. Sometimes, tightening the valve with a wrench is all it takes. However, if the valve is damaged or leaks after tightening, it may need to be replaced.

3. High Water Pressure
Water heaters are designed to handle a certain range of pressure. The pressure can stress the tank and its components when it gets too high. This often happens when the temperature is too high or a pressure relief valve malfunctions. If this valve starts leaking or dripping, it may be doing its job—releasing excess pressure. Still, checking your system's pressure levels is important to prevent further issues.

4. Faulty Temperature and Pressure Relief Valve (T&P Valve)
The T&P valve is a safety mechanism designed to release water when the temperature or pressure inside the tank gets too high. If this valve malfunctions, it may begin to leak constantly. While a leaky T&P valve might not seem like a big deal, it could indicate a dangerous buildup of pressure inside the tank that needs to be addressed immediately.

5. Cracked or Loose Inlet and Outlet Connections
The pipes that connect cold water in and hot water out are other potential leak sources. If these fittings become loose or corroded over time, they can cause drips or leaks. Inspecting these connections regularly can help you catch problems early and avoid water damage.

Don't Ignore the Leak
A leaking water heater might start as a small issue, but it can lead to significant water damage, higher utility bills, and mold growth. If you notice any signs of leaking, shut off the power and water supply to the heater and call a professional plumber. Early detection and repair can save you from more extensive damage and costs.