"Shaun Eli" wrote in message
...
I have an outdoor drain set in the concrete outside the entrance to my
basement. The water table around here seems to be rising, so when we
get an extremely heavy rain water backs up from the drain (it's not
coming from the rain falling down, it's coming up from the ground).

I see he http://www.plumbingsupply.com/floodguard.html

that someone makes a one-way valve that I could probably install if I
tore up the concrete and then poured concrete to finish the
installation. But it's a lot of work so I wanted to ask others before
I started...

Anybody ever use these? Do they work okay or might they leak under
pressure?

I had an anti backflow valve similar to the "float model" in the basement
drain of my previous house for 20 years that worked fine. Mine was a ball
that floated up to the underside of the drain and sealed it when a back flow
occurred. I needed to occasionally reach in the drain and clean off the
gasket this ball sealed up to on the underside of the assembly but other
than that no maintenance. In my case this plastic ball that was assembled
from two halves that had separated and was non functional when I moved
in....I learned that the hard was after the first heavy rain. After I
replaced the entire assembly it worked fine for the next 20 years and I
assume still does. Never leaked and I could tell when there was a backup
cause I'd see evidence of it when it would backup, but never over, in the
basement washtubs.