Water Heater Leaking from the Bottom
Finding a puddle under your water heater is never a good morning. The good news is that not every leak means you need a new unit... some fixes take five minutes. Let's figure out where the water is actually coming from before you panic.
What to Check Before You Call Someone
Check the drain valve at the bottom
Look at the spigot near the bottom of the tank. It looks like a garden hose connection. Water dripping from here is the most common "leak" and the easiest fix.
Fix: Tighten the valve by hand or with a wrench. If it still drips, cap it with a brass hose cap from any hardware store. If the valve itself is cracked, you can replace it for about $10.
Check the T&P relief valve discharge pipe
There's a pipe running down the side of the tank from the temperature and pressure relief valve. Water coming out of this pipe pools at the bottom and looks like a tank leak... but it's not.
Fix: A little discharge is normal, especially after heavy use. If it's running constantly, the valve might be faulty or your water pressure is too high. Replace the T&P valve ($20 part) or install a pressure reducing valve. Don't cap or plug this valve... it's a safety device that prevents your tank from exploding.
Rule out condensation
If your water heater is in a humid basement or garage, condensation can form on the tank and drip to the floor. This is especially common on newer, efficient units and during heavy use. Wipe the tank dry and check back in a few hours.
Fix: If condensation is the culprit, there's nothing to fix. It's normal. Improving ventilation in the area helps reduce it.
Look for water supply line leaks
Check the cold water inlet and hot water outlet connections on top of the tank. Water can run down the side of the tank and pool at the bottom, making it look like the tank is leaking.
Fix: Tighten the fittings. If they're corroded or the flexible supply lines are old, replace them. Braided stainless steel lines are cheap insurance.
Inspect the tank itself for rust or corrosion
Feel around the bottom of the tank where it sits on the base. If you see rust stains, bubbling paint, or water seeping from the tank body itself... that's internal corrosion. The anode rod (sacrificial metal inside the tank) has been eaten away and now the tank walls are corroding.
Fix: There is no fix for a corroded tank. Once the steel is rusted through, it's done. Shut off the gas or power and the cold water supply, then start shopping for a replacement.
When It's Time to Replace
If water is coming from the tank body itself... not a valve, not a fitting, not condensation... the tank has corroded through and replacement is your only option. This is especially common on units over 8-10 years old. Don't wait on this one. A small seep becomes a 40-gallon flood fast.
Read our full Water Heater replacement guide →When to Call a Professional
If you're not comfortable working with gas lines or electrical connections, call a plumber. Also call one if the T&P valve is constantly discharging (that could mean dangerous pressure levels) or if you can't identify where the water is coming from. A diagnostic visit is way cheaper than water damage.
This guide is for informational purposes. For gas leaks, electrical issues, or emergencies, call a licensed professional immediately.