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  • G&C Plumbing and Heating

Why is my water heater leaking from the bottom?

Updated: Oct 13, 2022


A leaky water heater is nothing to take lightly. Over time, the leaks could cause water damage to the flooring and any surrounding items in your utility area, and they’ll only get worse over time. If your water heater is leaking from the bottom, this almost always indicates a serious problem with your unit.

Wondering why your hot water tank is leaking, and if you should call a professional like G&C Plumbing and Heating to troubleshoot and repair your unit? Read on, and learn about the most common causes of hot water heaters leaking from the bottom.

1. Faulty Temperature & Pressure Relief Valve (Or Excess Pressure Buildup in Tank)

The T&P (Temperature & Pressure) relief valve is a safety feature found on all commonly-sold hot water heaters. It releases excess pressure from the tank through a tube directed at the floor – if the pressure gets too high in the tank, water will typically be sprayed through this tube as the pressure is relieved.

If you check your discharge tube and it’s wet, the T&P valve is probably the culprit. It may be faulty, and activating even when the pressure inside the hot water tank is normal. You’ll need to call a plumber to replace the valve and ensure your tank stops leaking.

In rare cases, though, your T&P valve may be functioning properly – and there may be too much pressure in your hot water tank. Pressure may build if the hot water tank is heating water too high (exceeding 140-145° F), which could happen with a faulty temperature regulator. Your hot water heater may be at risk of bursting if it exceeds its rated PSI, so contact a plumber for help immediately.

2. Drain Valve Leak

Another common cause of water heaters leaking from the bottom is a drain valve that’s not completely closed or is faulty and is leaking. The drain valve is used to drain out the tank to perform maintenance or repairs on the water heater, and is also used to drain sediment that gathers at the bottom of the tank.

If your drain valve is leaking, it may not be damaged. It’s possible that it’s just not completely closed. You may have knocked the handle loose at some point, loosening the drain valve slightly and allowing some water to drip out. Check the knob or handle and ensure it’s completely tightened.