My frost proof yard hydrant has been installed for 8 years . And the last 2 days when the hydrant was opened dirty water comes out for the first 2-3 seconds.
Never have had no problems to this point. We always turn the valve 100% open or 100% closed
I checked the city water meter and it showed a leak in that water line. Does the hydrant need to be replaced?

John r

If you let water sit in the pipe for longer period, it may get discolored from rusting galvanized nipple, or perhaps black nipple somebody put in during installation. I don't see it as something you should be too alarmed about. Next time you replace the valve, make sure the plumber replaces that nipple as well

Hope that explains

Milo

"I checked the city water meter and it showed a leak in that water line. Does the hydrant need to be replaced?" how does the meter show a leak in one particular line? I agree with Milo, not much to worry about but you could swap out the nipple but do not need a new hydrant.