Drainage and Gutters: Your Foundation's First Line of Defense
Nine out of ten basement water problems start outside. A homeowner walk-through for gutters, downspouts, grading, and drainage before the next heavy rain.
Updated April 17, 2026
Most basement water problems are solved outside, not inside. Before you consider interior waterproofing, spend 90 minutes walking the house. You'll be surprised how many "basement leaks" are actually "downspout dumping water against the foundation" problems.
Gutter and downspout checklist
- Clean gutters after leaf drop and again mid-spring. Clogged gutters overflow at the wall, drop soaks into soil within 12 inches of the foundation, and that's exactly where you don't want water.
- Check that every downspout extends at least 4-5 feet from the foundation. Splash blocks are a minimum; buried drainage lines to daylight are better.
- Look for sagging sections where water pools instead of moves. Reattach hangers or add new ones.
- At each downspout outlet outside, test with a garden hose for 5 minutes. Water should move away from the house — not sit or pool.
Grading walk-around
Start at every corner and walk the perimeter. The soil should slope AWAY from the house at least 6 inches of drop in the first 10 feet. If water can puddle anywhere within 3 feet of the foundation, that spot is working against your basement every time it rains.
Common grading failures:
- Beds or mulch piled higher than the foundation's waterproofing line.
- Patios or sidewalks that have settled and now slope toward the house.
- AC pads or generator pads tipped the wrong way.
- Areas next to decks where soil never got regraded after construction.
Simple homeowner fixes
- Extend downspouts. This is the single biggest ROI item on most homes.
- Regrade the first 10 feet outward with clean fill dirt (not topsoil, which settles).
- Install a generic splash block at every downspout as a minimum.
- Cap any window well drains that have clogged, and clear the wells seasonally.
When to bring Cornerstone in
If the grading can't be fixed by adding soil because hardscape is in the way, or if every rain still puts water in the basement after you've addressed gutters and grading, it's time for a real drainage design — possibly a French drain, curtain drain, or tied-in footing drain. We look at the whole system and design a solution instead of patching individual spots.
Free drainage evaluation: (812) 850-5320.