Why Is My Water Heater Leaking From the Bottom?

Troubleshooting Guide

The short answer

A water heater leaking from the bottom usually comes down to one of three things: harmless condensation, a leaking valve or fitting (often repairable), or a corroded tank that has rusted through (not repairable — the unit needs replacing). The deciding clue is the source of the water and the age of the heater: a steady puddle under an 8-plus-year-old tank almost always means the tank is failing. If it's actively leaking, shut off the water and the power or gas now, then call (540) 302-5580. We offer water heater service across Roanoke.

The 3 common causes

• Condensation (least serious). On a cold inlet line or a brand-new tank, a little moisture on the outside is normal and clears up as the water warms. If it's just a few drops and no puddle, watch it before worrying.
• A leaking drain valve or T&P valve (often repairable). The drain valve at the base and the temperature-and-pressure relief valve on the side can drip when worn or when pressure is high. These are parts a plumber can usually replace without touching the tank.
• A corroded, cracked tank (most serious). Water seeping from the very bottom seam, with no valve source, means the steel tank has rusted through from the inside. There is no patch for this — the heater has to be replaced, and it can fail suddenly and flood.

What to do right now

• Cut the power. Electric unit: flip its breaker off. Gas unit: turn the gas control dial to "off" or "pilot."
• Shut off the water. Close the cold-water valve on top of the heater; if it won't budge, close your home's main.
• Drain it if it's flooding. Attach a hose to the drain valve and route it to a floor drain or outside.
• Call a plumber. We'll confirm whether it's a valve fix or a replacement — no guessing.

Repair or replace?

If the leak is a valve or fitting, repair is usually worth it. If the tank body is leaking, or the heater is past about 8–12 years, replacement is the smart money — a failing tank will only get worse. Our repair-or-replace guide walks through the age-and-cost math, and we can price a same-brand swap or a switch to tankless. In older homes, sediment and age wear tanks out, so don't be surprised if a bottom leak on an older unit means it's simply time.

Related Guides & Services

• Water Heater Repair & Replacement
• Water Heater: Repair or Replace?
• Emergency Plumbing

Flooding now? Call (540) 302-5580 — describe the emergency and a plumber calls you back, day or night.