Certainly not "IN" the drains, but when I lifted a path in my first house,
the roots of a Poplar Tree at the bottom of the garden, extended right up to
the house. A distance of some 75 feet.

However, a neighbour to my last house, (we had gardens of some half an acre
and he had lots of trees), his drain was crushed by a tree root. I would
guess the tree was some 30 ft from the drain. These were some very well
established old trees.

Mike