Pressure release valves, (T&P, or temperature and pressure release), sit undisturbed for long periods. When opened either manually or automatically, sediment in the tank can get caught in the seat of the valve. If it does the valve will not seal properly and leaking will occur.

Try opening the valve again for about 15 seconds. Hopefully that will clear the valve. You may try several times. If the valve continues to leak you will have to replace it. Not difficult or expensive.

This is not uncommon for a pressure relief valve to leak after being slightly opened. Chances are there is some mineral scale around the inside of the valve. When your son got his shirt caught on it, it slightly opened and allowed a small piece to get stuck between the valve and the valve seat. First of all, BE CAREFUL. Most of the time, all you need to do is put a bucket under the valve, SLOWLY depress the lever to open the valve until a small amount of water has escaped the valve. This should help to clear the seat and stop the dripping. This may need to be repeated a time or two, but has always worked for me. Your pressure relief valve should be depressed yearly anyway to make sure its doing its job and not stuck shut. A stuck or blocked relief valve can be VERY DANGEROUS! Please don't get burned trying to do this!

hkstroud, Not sure why, but your answer was not showing up until I answered the question as well. Then, after I answered, your answer showed up, which was from yesterday. Interesting! Lol Thanks!