water heater draining hot water continuously from an outlet (seems tp valve outlet to me)
The water pressure in the house may be too high. These valves usually can be bought with a discharge over pressure of 125 or 150. Check the pressure in your house.  However these valves only leak or blow off above a 210 degree water temp. You may need a domestic expansion tank and/or a whole house PRV. If in doubt or you do not feel safe checking this tank, I would call a licensed professional (plumber) for help.