A driveway slopes down toward the garage. What detail determines whether that works?

A driveway that falls toward a garage turns the whole paved area into a catchment aimed at the building, and the volume involved is large — every square foot of driveway contributes. Slope alone does not decide whether that is a defect, because the arrangement is common and workable when the water is intercepted before it reaches the opening. The interception is the trench drain, a channel running across the threshold connected to a functioning outlet. The inspector's job is therefore to look for the drain and to assess whether it appears functional: present, clear of debris, and draining rather than holding water. Grate colour, slab finish, pavement thickness and door ratings are all irrelevant to where the water goes.

A trench drain across the garage threshold intercepts the runoff before it reaches the opening, which is what makes a downward-sloping driveway workable. Whether one is present and functioning is the detail that determines the outcome.

Site drainage should carry surface water away from the structure. Where grade requires a driveway to fall toward a garage, a trench drain at the threshold with a functioning outlet intercepts runoff, and inspectors evaluate whether such a drain is present and appears to be working.

Slope Toward Needs a Catch. Water aimed at the building is fine only if something catches it first. Find the trench, check it is clear.

Report whether the drain appears functional, not just present. A trench drain packed with debris or with a collapsed outlet is the same as no drain at all.

• •Judging the driveway by its construction rather than by where water goes
• •Confirming a drain exists without checking that it is clear and draining
• •Treating a storm-rated door as protection against surface water