How many years of age should a tpr drain valve be before it is replaced? I thought I remember it being every 5 yrs. This one was 12 yrs old.
I never knew it was a replacement part with a short life expectancy. I recommend testing it annually, along with maintenance as recommended in the owners manual.
It should be replaced every time the water heater is replaced, or as needed if it’s leaking and/or corroded.
That was my understanding.
Watts specifies that the vales should be inspected at least every three years. Inspection includes removal of the valve and its components. At that point, you might as well replace it. I think it’s mainly CYA language, but they ARE the manufacturer. So if the valve hasn’t been removed and inspected in over three years, it’s overdue.
It isn’t a drain valve, it is a relief valve.
I know that if the heater is working OK and it is dripping that is a good time to replace.
I have read somewhere that there is a recommended replacement time however, yet forgot about that as it is never mentioned on these forums.
May be time to research.
A better question is do you “test” a TPR… it (our SOP) says “Inspect” the Manu. would indicate that inspecting the TPR may include “tripping” the included trip/test at the top of the TPR. If the TPR is 8 years old… the home just sat vacant until 2 days before you inspected it, what do you think is going to happen when you “test/inspect” the TPR.
If you don’t think it’s gonna keep dripping/leaking after you leave and physically performed a TEST of the TPR… you’d be surprised, many continue to leak after being tested.
Now we’ve established a good reason not to test
Ok then, same house has been vacant for same time, water turned on a couple day before you get there. TPR and discharge pipe installed OK and that’s what you report as you DIDN’T TEST IT. 2 Weeks after they move in and the the water heater has warmed/cooled/cycled several days/weeks and “Guess What” now the TPR leaks.
Now we’ve established a good reason TO test?
“C. inspect the water heating equipment, including venting, connections, energy source supply system, and seismic bracing, and verify the presence or absence of temperature-pressure relief valves and/or Watts 210 valves;”
Just playing Devil’s advocate. Plumber I know tells me he has had a lot of business replacing TPR’s or just replace the WH for that matter. You can’t blame 'em, who wants to touch a 10 year old, corroded WH tank? Also, regulators seem to need service a lot of the time when home is moved into. Probably sediment/diaphragm etc.
rem by me 
How often is the water heater itself supposed to be drained & cleaned? If you’re thinking of writing up failure to perform recommended homeowner maintenance, you’re going to have a very long report.
Thats what I am thinking.