Hello Karen,

You may want to ask the opinion of a certified arborist about root risks. To the best of our knowledge, roots cannot break into intact pipes, but could take advantage of already-cracked pipes or leaking pipe joints. Moisture-loving trees like Willow might be among the first to take advantage of that scenario, but they would not be the only tree which could do so.

As a separate concern, willows tend to mature into large trees (though this will depend on what species they are) and having a tree that size so close to the house may risk other damage, such as from limb breakage. Willow doesn't have the reputation of being a terribly sturdy tree when it comes to wind damage, though usually what's shed most often are smaller branches and twigs.

Tree roots generally don't grow well, if at all, where the soil is too compacted. Those conditions don't allow for optimum levels of what they need for growth - mainly oxygen in this case, but also moisture and nutrients. Soil underneath driveways and around house foundations is fairly compacted - it needs to be for stability, but it's also a byproduct of construction. That said, it's still possible for aggressive tree roots - especially if they don't have many other options for elsewhere to grow - to buckle pavement or invade already-cracked foundations. Willow can have relatively shallow roots as part of their normal growth; others known to grow shallowly include Maple, Birch, Beech, and Magnolia. Any tree, though, can have shallower-than-usual roots when they need more oxygen due to soil in their root zone being very compacted. This shallow growth is what threatens sidewalks and some driveways since roots increase in girth as they age.

Miri