Sorry, probably need a bit more explaining here. We found the leak
already. The leak was actually in a hot water pipe between the hot water
heater and the kitchen sink. We found it through acoustics. We abandoned
that line and ran a new one through the attic. When the pipe gave way
water that escaped built up under the slab until it forced through at the
first point it found. This happened to be the path the roots I found also
took. I know this is where the water came up because the entire room was
filled with silt from under the foundation. I've never had any problem
with roots before, but I do know how destructive they can be. I didn't
even know about the roots until we moved the toilet yesterday to begin
sheetrock repair. But now that I do things make much more sense.

My question here was really about how to defend against the encroaching
root system and how to clean them out of there before they get even more
out of hand. I'll try to get some pictures on a website for visual
tomorrow.

I'll try killing them off with a poison an see if anything outside dies. I
don't have anything outside that I prefer more than my foundation that's
for sure.

Thanks,
tM
Live in Arizona, by any chance? Friend used to have Oleander roots from
the neighbors hedge regularly put a shoot up the drain hole in his bathtub.
I had a hot water line break under my slab, also. Based on the water bill,
I figured about 30,000 gallons leaked out before I figured out something was
wrong. I was told the expansion/contraction of the water line against a
rock under the slab was probably the culprit, but I think more likely it was
the 90 pound water pressure from the city. After the second leak a year
later, I added a pressure regulator to the house. The 90 pound pressure
used to unscrew the sprinkler heads in my yard. Now, I'm back in Illinois
where we never seem to have those water pressure problems but unfortunately,
this year we do seem to have Arizona heat.
Tom