Standing water accelerates asphalt deterioration by seeping into cracks, weakening the sub-base, and causing frost heave in cold climates. Proper drainage starts with correct grading — a minimum 1–2% slope away from structures. French drains and channel drains can redirect water on flat lots. Keep edges clean and intact, as edge crumbling is often the first sign of drainage failure. Addressing drainage during installation is far cheaper than repairing water-damaged asphalt later.

How Water Destroys Asphalt

Water that sits on or under pavement works its way into the base, weakening the support beneath the surface. In cold climates, trapped water freezes and expands, prying cracks open and lifting the asphalt. The result is potholes, depressions, and crumbling edges.

The Role of Proper Grading

A driveway or lot should be graded so water flows away from the surface and toward a drainage point — never pooling in the middle or against a structure. A slope of about 1 to 2 percent is usually enough to shed water without being noticeable underfoot.

Drainage Systems That Help

• Channel or trench drains across low points and entries.

• Catch basins connected to a stormwater outlet.

• Properly graded swales to direct runoff away from pavement.

Don’t Forget the Edges

Edges are where water most often sneaks in. Maintaining firm, supported edges and keeping soil and vegetation from trapping moisture against the pavement protects the most vulnerable part of the surface.

Drainage Pays for Itself

Investing in good grading and drainage during installation costs far less than the repeated repairs caused by poor water management. When it comes to asphalt longevity, controlling water is the highest-leverage decision you can make.