Signs of a Leaking Drain Valve. Water on the floor at the water heater’s base is a sure sign of a leak. The water might be coming from the temperature and pressure relief valve (T&P valve), though.

The Sedna kit (I evaluated the 0.75-inch Sinopé model number VA4200WZ-K5) includes the valve and five leak sensors, two of which have extension probes that extend their reach.