Sounds like a bad check valve. The water is draining back down the pipe, and
when the pump kicks on, it sucks up air first.

"Dennis Straussfogel" wrote in message
...
I have an old (30 yr?) bladderless pressure tank on a shared (4 houses)
well. It appears that over the last six months, air has been entering
the tank somehow and ending up in the house water lines. I've been
bleeding air out of the tank about once every week to ten days and that
corrects the problem temporarily. My question is: is there any way (such
as a particular pump failure mode) that would allow this to be
happening, or is the only thing that could be wrong is that we are
pumping the well faster than it can recover? (There's no obvious reason
to think the water table has dropped in the last year.)

When I lived in New Hampshire (The Granite State), there was a process
called "hydro-fracting" which involved dropping dry ice down the well
shock cooling the bedrock and opening up the fissures to allow faster
well recovery. I now live in Northern British Columbia (on probably clay
and gravel), so my second question is: if we are overpumping the well,
what can be done about it?

Thanks a lot for any information.

Denny