ok, I have a frost free hydrant at my outdoor wash stalls. It was put in a place where my horses would get a lead wrapped around it and pull it out of the ground. Once it came competely out of the ground and had to be fixed, once it just came loose-pipe would move several inches.
Ok, so I started noticing water pooling at the bottom so I assumed it was leaking underground. I called a plumber out to fix it. He said that the water I saw was just the water the frost free just sucked back out of the pipe (hence-what makes it frost free). Well, they charge $80 just to come out so I went ahead and had him move the hydrant away from where the horses can get to it. Underground it uses pex (?)-flexible plastic lines.
I still see water pooling under the hydrant. It has been dry here for 2-3 weeks. I don't even use this hydrant every day, maybe once or twice a week. Is this sucker leaking or am I paranoid? Its enough water that my dogs drink from the puddle.
In my novice opinion- it is leaking. When the water sucks back into the pipeline from the hydrant- it should not exit the pipes anywhere. I'm sure someone else will post with more detail- but I say yes it is leaking and I'd call the guy back out to fix it since he didn't reinstall it correctly.
The hydrant should be letting the water back down into the ground, not on top of the ground. Ours has to be 3 foot below ground so that is is below the frost level. If you were using it ALOT, you might see some on top, but I haven't. Anytime I've seen water on the ground level it is because the hydrant needs to be tightened at the top and you should see it leaking down the pipe to the ground.
There should be no water, apart from what you spill on the ground when using the hydrant, around the base of the hydrant. If it is draining out of the stand pipe, as it is supposed to, and the plumber didn't give it a good drainage sump, then yes, that water could eventually migrate up to the surface and that, IMHO is not a good thing. At that point, sump water filled and rising up the stand pipe, your stand pipe cannot drain fully and the whole frost free feature has been disabled. We had one that didn't fail due to freezing, it failed due to persistent soaking from a too small drainage sump causing it to rust through at a weak point.
If you haven't used the hydrant at all for a while then yes, you may have a leak in the hydrant innards or somewhere in the pipe. You'll have to dig it up to find out but I think that if you look up Tom Kings old posts he has links and info on how to take them apart.
Water is supposed to run down out of the pipe on a freeze proof hydrant. That's the way it remains freezeproof. It is not "sucked back out", but simply drains by gravity above the cutoff washer below the drain hole near the bottom. When you pull the handle up to let the water flow the drain hole is closed by the washer holding assembly at the bottom. When you push the handle down, it pushes the washer down to shut the flow off at the bottom and opens the drain hole.
If you are seeing water pooling at the bottom, it most likely does not have enough open space to drain into underground like it needs. Probably when it got pulled up the rock under it got filled with dirt.
I like to bury an 8" cinder block vetically under one and use a wheelbarrow full of clean crushed rock around that. The important part about having rock under it is not the rock, but the spaces between the rocks.
The water needs to have somewhere to go out the bottom quickly so it doesn't stay in the stand pipe long enough to freeze.
It probably needs to be dug up again and the drain system improved.