Drainage and grading: the yard's job is to move water away

A house sits in a bowl or on a mound, and which one is the difference between a dry basement and a wet one. Foundations are not waterproof. They are built to be kept dry by the ground around them, and when that ground settles, gets paved, gets a flower bed built against it, or simply was never graded right, water goes where gravity sends it.

The good news is that the fixes run from an afternoon with a wheelbarrow to a day with a small excavator, and the cheap ones solve most cases.

Walk it in the rain

The best time to diagnose drainage is during a hard rain, in a raincoat. Watch where water comes off the roof, where it goes when it hits the ground, where it puddles, and where it runs toward the house instead of away. A hose on a dry day does the same thing more slowly.

The order of fixes

• Downspouts first. Extend every one at least four feet from the foundation, further on the uphill side. Splash blocks, hinged extensions, or a buried line to daylight. This is the single most common fix for a wet basement and the cheapest.
• Grade second. The soil should fall six inches over the first ten feet away from the house, all the way around. Add soil, a clay-heavy fill rather than topsoil, packed against the foundation and sloped, and keep it below the siding and the top of the foundation. Mulch beds and edging against the house often trap water; take them down.
• Window wells. A well that fills is a window that leaks. Clear the gravel, add a cover, and make sure the well drains.
• Surface drains and swales. A shallow, grassed ditch that carries water around the house to a low corner, or a channel drain across a driveway that slopes toward the garage.
• French drains. A gravel trench with a perforated pipe, buried along the wet side of the house or across the yard, draining to daylight, a dry well or a storm drain. Effective and more expensive; make sure it has somewhere to send the water.
• Foundation drainage. Excavating to the footing, waterproofing the wall and installing a drain tile is the full fix, and the most expensive, and almost never needed if the first four were done.

The sump pump

A sump pump is not a drainage fix. It is what you do when water is already inside. It should have a check valve, a battery or water-powered backup for the storm that knocks out the power, and a discharge that goes well away from the house rather than back into the soil beside it. Test it every spring with a bucket of water.

Trees and pavement

A driveway or patio that slopes toward the house is a river in a storm; a strip drain at the edge or resurfacing with the right pitch fixes it. Roots of large trees near the foundation move soil and can clog drain lines.

Who does the work

A landscaper or grading Pro handles downspouts, grade, swales and French drains. A basement waterproofing Pro handles the interior systems and foundation work, and a good one will tell you to try the outside fixes first. If a Pro's only answer is an interior drain and a pump, get a second opinion from someone with a shovel.