Grade around a house should generally fall away from the foundation over the first several feet because:

Every strategy for keeping a foundation dry is cheaper and more reliable the earlier in the water's journey it acts. Grade sloping away moves surface water before it has a chance to infiltrate, which is the earliest possible intervention. Once water soaks in adjacent to the wall it becomes hydrostatic pressure against the foundation, and from there the only remaining defences are the damp-proofing on the wall and the footing drain — both buried, both expensive to correct, and both prone to failing invisibly over decades. The disturbed backfill beside a foundation is also more permeable than undisturbed soil, so water that soaks in near the wall preferentially travels straight down along it. That is the whole logic of positive grade: intercept the water while it is still on the surface and still easy to redirect.

Positive grade moves surface water away before it can soak into the backfill beside the wall. Once water infiltrates it becomes hydrostatic pressure against the foundation, and the remaining defences are buried and costly to correct.

Positive drainage requires grade to fall away from the foundation over the first several feet. Backfill adjacent to a foundation is disturbed and more permeable than surrounding soil, so water infiltrating there travels down along the wall to the footing.

Stop It on the Surface. Every foot of water you turn away up top is water the damp-proofing and the footing drain never have to fight.

Check the grade after mulch, planting beds and settled backfill are accounted for. Original grading is frequently reversed over the years by landscaping.

• •Treating grading as a landscaping preference
• •Addressing interior symptoms before correcting exterior grade
• •Missing grade reversal caused by settled backfill or added beds