Posted: 31/01/2015 at 15:31
Willow trees can certainly be a problem regarding drains / subsidence etc, but if your house and these trees have coincided together for donkey's years I wouldn't be too concerned that it was suddenly going to start causing a problem.
Reading your post, however, it sounds as though you are more concerned that they are starting to lean and might eventually topple. I suppose that's possible but probably unlikely unless there is a combination of very wet ground and very high winds.
Boughs of willow trees will, however, break off and a friend had a very mature willow which was almost split in two by high winds. It was cut hard back and suffered no lasting damage - actually looked much better in the years after the haircut.
If you are concerned about these trees the most sensible thing to do would be to get a qualified, professional tree surgeon out to look at them. The good companies (in my area) make no charge for quotations & assessing situations such as this - and they should be able to either allay your fears or suggest what action needs to be taken.
Who owns the land the trees are on? Can you discuss the matter with them first? - you will need to get their consent to do any work or even to access the site for an assessment - unless, of course, you believe your house to be in imminent danger.