There is no single distance that makes every tree safe or unsafe. Species, mature size, foundation type, branch structure, root conditions and tree health all affect whether proximity is a problem.
Look beyond trunk distance
A tree can be close to a house yet structurally sound, while a farther tree with a major defect can present greater risk. Crown spread and potential failure direction matter.
Common conflicts
Roof and siding clearance, gutters, roots, driveway lifting, sewer lines, shade and storm loading are common reasons homeowners ask about trees near structures.
Assessment before removal
If the concern is risk rather than simple preference, an assessment can help distinguish a manageable pruning issue from a removal issue.