You can install the best waterproofing system money can buy, and it'll fail if the grading around the foundation is wrong. Water management starts at the surface, well before it reaches the wall. This is one of those areas where cutting corners during site work shows up as callbacks five years later.
The Basic Rule
Grade must slope away from the foundation — minimum 6 inches of drop over the first 10 feet. This is code in most jurisdictions (IRC R401.3) and non-negotiable from a moisture standpoint. Even 6 inches in 10 feet is marginal in heavy rain areas. Where you can, aim for 1 inch per foot for the first 6 feet.
Why Builders Get This Wrong
It's almost always a sequencing problem. Rough grading is done correctly. Then landscaping contractors, HVAC crews, plumbers, and electricians all dig around the foundation. Each one backfills loosely. By the time the final grade is established, it's settled unevenly and water is running toward the house. Assign responsibility for final grade verification before occupancy — don't assume it happened.
Window Wells
Basement windows below grade require window wells with proper drainage. The well must be wide enough to allow the window to open (minimum 9 inches clearance from glass to well face). The bottom of the well needs 6 inches of coarse gravel over a drain that connects to the footing drain system. A window well without drainage is a water collection bowl pointed at your basement.
Downspout Discharge
Gutters and downspouts are useless if they discharge water against the foundation. Extensions should discharge at least 6 feet from the foundation — ideally connected to an underground pipe that daylights well away from the structure. Every downspout spilling against a foundation wall is a direct assault on your waterproofing system.
Swales and Catch Basins
On sloped lots or where neighboring properties drain toward the building, swales are critical. A swale intercepts water and redirects it around the structure. Size swales based on the contributing drainage area — undersized swales overflow and defeat the purpose. Catch basins in low spots connected to underground drainage handle what surface grading can't.
Final Inspection
Walk the site during a heavy rain before you hand over the keys. Where does water go? Where does it pool? Are all downspouts flowing and discharging properly? Problems visible during construction are cheap to fix. The same problems found by the homeowner two years later become expensive disputes.