How to Spot a Leak: The Most Common Water Heater Leaks

A leaking water heater isn’t just an annoyance. It’s a sign that there’s something deeply wrong.

Left unchecked, even a small leak can lead to bigger problems, from water damage to complete system failure. The key is catching leaks early before they turn into costly disasters.

Not sure what to look for? Worried you won’t know how to fix a leak if you do spot one? Here’s how to spot the most common water heater leaks and what to do about them.

1. Dripping from the Pressure Relief Valve

Your water heater’s pressure relief valve (PRV) is a safety feature that’s supposed to release water if pressure gets too high. A small drip now and then is normal, but constant leaking could mean:

• Your system is overheating.

• The pressure is too high.

• The valve itself is faulty and needs to be replaced.

What to do: Check your system’s pressure gauge. If it’s too high, you may need professional help. If the valve won’t stop dripping, it likely needs to be replaced.

2. Leaking Tundish

If you have an unvented system, your tundish acts as an early warning system. Water flowing through it means your pressure relief valve is activating. An occasional drip is fine, but steady water flow means there’s a problem with your expansion vessel or PRV.

What to do: Don’t ignore a constantly leaking tundish. It’s a sign that your system isn’t handling pressure correctly and needs expert attention. And remember, under UK rules, only G3-qualified engineers should service/maintain unvented cylinders. This is not a repair you should handle yourself.

3. Water Pooling at the Base

Spotted water around the bottom of the cylinder? If you see water collecting at the bottom of your heater, it could mean:

• A loose connection on the inlet or outlet pipes.

• A failing drain valve (often due to sediment buildup).

• A cracked tank—the worst-case scenario, requiring a full replacement.

What to do: Check the fittings first. Tightening a loose connection might solve the problem. If the tank itself is leaking, you’ll need to replace it. Get in touch with EasyFlow to learn more about your options when it comes to replacements.

4. Leaky Pipes or Connections

Over time, pipe fittings and joints can loosen or corrode, leading to small drips or full-blown leaks. Signs of trouble include:

• Dampness or water stains on the pipes leading to and from the heater.

• Visible corrosion or rust on fittings.

• Water pooling under nearby pipes.

What to do: If tightening connections doesn’t stop the leak, call in a professional before things get worse.

5. Condensation or “Sweating” Heater

Sometimes, what looks like a leak is just condensation forming on the outside of the tank—especially in humid conditions. But if the moisture is excessive, it could mean your heater is working too hard or that there’s an internal leak forming.

What to do: Wipe the tank dry and check if moisture returns quickly. If it does, investigate further for hidden leaks.

Don’t Ignore a Leak—Fix It Fast

A small leak today can lead to major damage tomorrow. If you spot water where it shouldn’t be, don’t wait—get it checked out before the problem worsens.

Need Leak Detection and Repairs?

At EasyFlow, we specialize in diagnosing and fixing water heater leaks before they become major issues. Contact us today and keep your system running safely!