Boats leak from the bottom. But a house can leak from the top or the bottom.

After the heavy rains we’ve had in North Georgia this month, many homeowners found water intruding into the basement, or a saturated crawl space with standing puddles, causing floor joists to rot. In almost all these cases, inadequate drainage around the house is the cause.

Builders recommend routing water 15 feet away from the foundation walls. This doesn’t mean that the soil there needs to be bone dry. Capillary moisture, which is contained in the pore spaces of the soil, is beneficial to plants and won’t hurt anything else. It’s gravitational moisture, or water traveling rapidly through the soil layer, that causes problems.

Where there’s an in-ground swimming pool installed next to the house, water gets easily trapped between the pool walls and the house foundation, from where it finds its way into the basement. The cinderblock walls commonly used for foundations aren’t water-tight, and putting a layer of sealing paint inside the basement walls won’t stop the flow permanently all by itself.

The first item to fix are the downspouts of the roof gutters. If there aren’t any gutters, the waterfalls along the roof line are a major cause of leaks and wood deterioration. Gutters and downspouts are a necessity for a healthy home.

Where they are discharging water straight to the ground, drain pipes need to be installed that collect the runoff and route it as far from the foundation as possible. Those widely sold black flexible corrugated pipes aren’t the best solution for building such a storm sewer system, because all those wrinkles collect dirt and roots inside, and after a few months the pipes tend to get clogged up and stop functioning. Much better are smooth 4-inch diameter PVC pipes because they stay clean inside.

Laying the drain pipes and connecting them to the downspouts with Y-junctions isn’t a tough job for a do-it-yourselfer. To capture rainwater falling directly on the ground, the soil should then be sloped away from the house. In most cases, these measures provide enough drainage to keep the foundation trouble-free. This job, which is simple but requires some digging, avoids the costly procedure of having it done professionally. In that case, it would mean getting the ground dug up by a contractor, exposing the foundation, sealing the walls, and installing commercial grade drains.

Rudi Kiefer, Ph.D., is a professor of physical science and director of sustainability at Brenau University. His column appears Sundays and at gainesvilletimes.com.