5 Drainage Jobs You're Forgetting Before Rainy Season Hits

TL;DR: Before rainy season, check five things: downspout extensions (water should land 5-10 feet from the foundation), yard grading (a 6-inch drop over the first 10 feet away from the house), sump pump function (test it with a bucket of water), window well drains, and any yard catch basins or French drains. Skipping these is the single biggest cause of wet basements and slab damage each fall and spring.

_Last reviewed: July 2026 · 7 min read_

Most people think about drainage the moment water is already in the basement. By then you're not doing maintenance, you're doing damage control, and that costs a lot more than an afternoon with a shovel and a hose. Here are the five jobs that get skipped every year, and what happens if you skip them again.

Okoniq Property Hub lets you log each drainage check with a photo and a date, so you're not guessing next fall whether the sump pump test actually happened.

Are your downspouts actually moving water away from the house?

Most downspouts dump water within 12 inches of the foundation, which is close enough to soak right back into the soil around your footing. The fix is a downspout extension that carries water at least 5 to 10 feet away, and ideally to a spot where the ground slopes further downhill.

Walk the perimeter after the next rain and watch where water actually lands. If you see a puddle forming near the foundation, or if the extension has come loose and is just draped on the ground, that's your first fix. This is one of the downspout mistakes that send water into your basement, and it's also the cheapest one to correct — a rigid or flexible extension runs $10 to $25 per downspout.

While you're out there, check for the signs your downspouts are dumping water in the wrong place, including staining on siding, erosion trenches in mulch beds, and gutters that overflow during moderate rain instead of heavy storms.

Is your yard grading sending water toward the foundation instead of away?

Correct grading drops about 6 inches over the first 10 feet moving away from the house. If the soil near your foundation is flat, or worse, sloping toward the house, every storm pushes water straight at your basement walls or slab.

Grading settles over time, especially in the first 2 to 3 years after a house is built, as backfill soil compacts. A simple test: after a rain, check whether water pools against the foundation for more than an hour. If it does, you likely need 2 to 4 inches of added topsoil sloped away from the house, tamped and graded by hand. This is a half-day job for most single-story homes and one of the few drainage fixes that doesn't need a contractor.

Poor grading is also a quiet contributor to slab problems. If you've noticed cracks or damp spots inside near exterior walls, it's worth reviewing the signs of a slab leak under your floor before assuming it's just surface moisture.

Does your sump pump actually work, or are you assuming it does?

Test it before the season starts, not during the first storm. Pour a 5-gallon bucket of water into the sump pit and confirm the float rises, the pump kicks on, and water discharges outside through the pipe without backing up.

A sump pump that sat idle all summer can fail from a stuck float, a clogged check valve, or a dead battery in the backup system. Replace the battery backup every 3 to 5 years even if it seems fine, since batteries degrade whether they're used or not. If your home doesn't have a battery or generator backup and you've had power outages during past storms, that's the gap to close before this rainy season, not after a flooded basement.

Are window wells and area drains clear of debris?

Leaves, mulch, and dirt build up in window wells and area drains all summer, and a clogged well fills like a bathtub during heavy rain, pushing water against the window seal. Clear wells down to the drain grate and confirm the drain pipe underneath isn't blocked with silt.

If a window well doesn't have a drain at the bottom at all, a French drain tied into your yard's drainage system or a sump pump connection is worth adding, especially if that window sits below grade. Clogged gutters overhead make this worse too, since overflow often lands directly in the well below — a connection covered in why your roof is aging faster than it should, since the same debris that ages a roof also clogs everything downstream of it.

What about catch basins and French drains in the yard?

Yard catch basins and French drains fail quietly because they're buried and easy to forget. Lift any visible grates and check for silt buildup, then run a hose to confirm water actually flows through the pipe instead of just sitting in the basin.

If a French drain outlet is buried under leaves or has collapsed at the discharge point, water backs up underground and resurfaces somewhere you don't want it, often right next to the foundation it was supposed to protect. A once-a-year flush with a garden hose catches most of these problems before the first real storm.

FAQ

How much rain does it take to overwhelm bad drainage?

As little as half an inch in an hour can overwhelm a clogged gutter or a downspout that ends too close to the foundation, especially on a roof larger than 1,500 square feet.

How often should downspout extensions be checked?

Twice a year, once before rainy season and once after winter, since freeze-thaw cycles and lawn equipment commonly knock extensions loose or crush them.

Can bad drainage cause foundation cracks?

Yes. Repeated saturation next to a foundation causes soil to expand and contract, which over several seasons can create hairline cracks that widen into structural issues if left uncorrected.

Is a sump pump necessary if I've never had water in the basement?

If your home has a below-grade basement or crawlspace and sits on clay-heavy soil, a sump pump is cheap insurance, typically $150 to $400 installed, against a single flood event that can cost $5,000 or more in cleanup and repair.

What's the cheapest drainage fix that makes the biggest difference?

Extending downspouts at least 5 feet from the foundation. It costs under $25 per downspout and addresses the single largest source of foundation water on most homes.

This is educational information, not engineering or legal advice. Call a licensed drainage contractor or structural engineer if you're seeing recurring water intrusion or foundation cracking.