Some of the earliest water heaters were not equipped with a temperature and pressure relief valve. These manufactures soon realized just how dangerous a water heater can be without one. During a catastrophic tank failure these early water heaters were literally shooting through the roof like a missile. Not to worry, all modern day water heaters are now equipped with a temperature and pressure relief valve. The T&P valve is a small brass valve usually located at the top middle section of your water heater. It is a safety valve designed to relieve pressures above 150 psi and temperatures above 210 degrees. During a catastrophic tank failure, your T&P valve would automatically open relieving the pressure. This ensures your water heater stays where it was installed. This can still make a mess if your T&P valve is not piped to the outside but usually will not involve anyone getting hurt. We have encountered homeowners in the past who have capped this valve off or connected a garden hose to the T&P to wash down the garage. If your T&P valve has a small drip, contact a professional to inspect your water heater and replace your T&P valve. Although capping off this valve stopped the leak, it created a much more dangerous problem.