In article , Janet
Baraclough.. writes

It's not so much undermining that's the risk to drains/pipes, as roots
invading and blocking them, and that can happen to plastic ones. Pipes
settle over time (especially near trees). Wherever there's a join it's
possible for a small drip to leak from the seal, and where that drip
oozes out, a tiny root finer than a hair can enter. Then the root
reaches food/water and expands until it fills and blocks the pipe.
Poplars are notorious for it.

Janet.


Many years ago, I lived in a gatehouse at the end of an avenue of limes.
Water pressure was never good, but one year it started to get worse and
worse. The landlord (fairly half-heartedly) started looking all over
the estate for where the leak might be - including getting a trench dug
right across the field. After about 18 months, we ended up with hardly
a trickle of water. Eventually, he got experts in who dug up the old
piping along the avenue. The feed to our house was absolutely full of
tree root for a very long length.

As soon as their iseven a minor leak, tree roots seem to sense it and
head for the area toot sweet

--
regards andyw