Posted: 19/06/2013 at 06:48
I think that in Britain we get really anxious (and with good reason) because on clay soils large trees can take up a lot of water and cause contraction of the soil around the foundations leading to subsidence. It's not quite such a problem on other types of soil as far as I'm aware.
In this case, whether the roots will cause damage to the drains, it depends a lot on where the drains are in relation to the tree? Have you had the drains checked?
Bays can grow up to 20ft or more - whether it will damage the foundations depends a lot on the age of your house and how it was built.