Home Drainage and Grading Guide: Keeping Water Away from Your Foundation

The Critical 6-Inch Rule

The ground should slope away from your home's foundation at least 6 inches over the first 10 feet (6% slope minimum). This single principle prevents the majority of basement water infiltration and foundation damage. If your grade is flat or slopes toward the house, water pools against the foundation and eventually enters.

How to Assess Your Drainage

• Walk your property after heavy rain and identify areas where water pools
• Check gutters — improper grading near downspouts is extremely common
• Look for soil erosion channels that indicate water flow paths
• Check basement walls for efflorescence, staining, or actual water infiltration

Solutions by Severity

• Simple regrading: Add topsoil and slope away from foundation. $200–800 DIY for average area.
• Downspout extensions: Extend downspouts 4–6 feet from foundation. $10–50 per downspout. Highly cost-effective first step.
• Swales: Shallow, grass-lined channels that direct surface water away. $500–2,000 DIY.
• French drains: Perforated pipe buried in gravel-filled trench, directing water to daylight or a dry well. $1,000–5,000+ depending on length and depth.
• Interior drainage systems: Basement perimeter drainage with sump pump — for when exterior solutions aren't feasible. $5,000–15,000. Addresses symptoms rather than causes.