Water is seeping up around relief valve threads. Tried tightening but could not get it any tighter.
Use plumbers tape. Take of the valve and put a 3 or 4 wraps of plumbers tape and put it back on it should be good then.
Donald; Don't try to tighten it, or replace it, it will fail. Lower the thermostat to no more than 120F degrees, and start shopping for a new water heater.
Is the valve open? If not - i'd open it - the strain of the tank is forcing water out around the valve - with the aid of opening the valve you're going to relieve probably the most pressure. Additionally - turn off the energy and phone a plumber in the morning- your hot water tank can blow up - no longer just right.
Shut off the cold water supply to the water heater and also shut the gas supply or the heater control. Drain the water heater (this will drain all your house hot water as well). Open a hot water sink valve to let air enter. Drain the water until the water is lower than the threads. Cut or unsolder the joints needed to remove the threaded fitting. Remove the fitting, and bring it to a local plumbing supply house and get a new one. Install the new one with teflon tape. Shut the sink hot valve. Open the cold water supply valve on the water heater slowly. Check for any leaks. If its leaking, start over. If not resolder the copper joints together, and remember to purge the air through your sink again. Or just call a plumber or an HVAC company.
lift few times pressure relief release, just to check if it is not jammed and it is not holding too high pressure. 1. prepare thread tape or goo, if no experience - goo is better, available in hardware and plumbing stores, you need just few drops 2. cut off water supply to the heater 3. relieve pressure in the heater (just open any hot water tap (fawcet) and let water out) 4. remove the valve completely, 5. with wire brush clean the thread, check for damage to the thread on the cistern as well and clean it too 6. wind several layers of teflon tape or well grease with plumbers hot water goo 7. remount the valve 8. close hot water tap which was used to release the pressure 9. open water supply to the heater 10. open hot water faucet to let the air out, close when stop gurgling and water pour out 11. check for leaks, if no leaks - JOB WELL DONE! 12 if any leaks find, repeat 1 to 4, wind few more layers of teflon tape, if goo was used - you need to use tape as well then. 12. repeat 7 to 11 and that is all...
