when ever we use large amounts of water, we seem to be getting some kind of sewage odor (not like rotten eggs) from the hot water tank pressure relief valve drain.... is this drain trapped? should it be filled with water?
Yes. Any drain that ties into your house drainage system should have a trap and it should have water in it. This is a common problem with floor drains that don't get much usage. The water evaporates and allows sewer gas to enter the home.
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