The water heater relief valve leaks for four reasons, I will explain each
reason in detail but first please read the following
water heater relief valve warning
The first reason a water heater relief valve leaks is.
The valve is old and it starts to leak, I have seen them start to leak
within a years time, if your relief valve is a few years old and leaking,
you should have it replaced regardless of why it is leaking.
Just a reminder replacing a water heater relief valve can be very dangerous,
it may be best to have it replaced by a pro. To find a local
professional plumber please call 1-888-330-6270.
The second reason a water heater relief valve leaks is, The water has gotten
too hot, if the temperature of the water in the water heater reaches above
210 degrees F the relief valve will leak or even blow off, this is why the
outlet of the relief valve must be piped to about 6 inches from the ground,
you would not want to get a blast of 210 degree F water in the face.
The relief valve may leak before the temperature gets to 210 degrees F
because of the extra expansion of the water as it heats.