Drainage and grading cost

Regrading around a house costs $500 to $3,000, typically around $1,500. Adding a drainage system costs $1,500 to $8,000. Together they are the cheapest structural insurance a house has, because most foundation and basement problems begin as water sitting against a wall.

The soil around a house settles over decades. What was a slope away from the foundation when it was built is frequently level or reversed by year thirty.

What it costs

The numbers that matter

Six inches of fall in the first ten feet away from the foundation. That is the figure, and it is what most codes require for new construction.

Six inches of foundation exposed above the finished grade, so siding and framing are not in contact with soil.

Two inches above a paved surface where a patio or path meets the wall.

Downspouts discharging six to ten feet away, minimum, and further on clay soil.

Take a level and a straight board along each wall and check. Most houses over thirty years old fail at least one of these somewhere.

The cheap fixes first

In order of value per dollar:

1. Downspout extensions. Ten dollars each, twenty minutes, and they move thousands of gallons a year. Nothing else on this page comes close on value.

2. Cleaning and repairing the gutters. An overflowing gutter waters the whole wall.

3. Moving the mulch back. Mulch and soil piled against siding holds moisture against the wall and often buries the weep screed or the siding's lower edge.

4. Regrading. Adding soil to build a slope away from the house, keeping six inches of foundation exposed.

5. A swale, a shallow shaped channel that carries surface water around the house rather than through it. It is landscaping rather than plumbing and it is invisible when planted.

Only after those does buried pipe become the answer.

French drains, honestly

A French drain is perforated pipe in a gravel trench wrapped in filter fabric, which collects water in the soil and carries it away.

Two things decide whether it works, and both are invisible once the trench is filled:

Slope. It must fall continuously toward the outlet. A drain with a flat section holds water and silts up.

An outlet. The water must have somewhere to go: daylight on a lower part of the site, a dry well, or a storm connection where permitted. A French drain with no outlet is a trench that fills up.

Ask where the water leaves, and then go and look at that point. That single question separates a drain that works from one that does not.

Fabric matters. Sock-wrapped pipe in unwrapped gravel silts up in a few years. Fabric should line the trench, not just the pipe.

Frequently asked questions

Can I regrade myself?

Adding topsoil and shaping a slope is achievable with a wheelbarrow and a rake for one elevation. Do not raise the grade above the top of the foundation, and do not bury siding or a weep screed. Machine work and drainage pipe are contractor territory.

What soil should I use for regrading?

Clay-rich fill against the foundation, which sheds water, topped with topsoil for planting. Sandy or loose topsoil against the wall lets water straight down to the footing.

Where can I discharge the water?

Onto your own property, away from the house, and not onto a neighbor's land. Many jurisdictions prohibit connecting to a sanitary sewer and some prohibit storm connections too. Check locally before trenching.

Will this fix my wet basement?

Frequently, and it is what should be tried before any interior system. Surface water handled properly resolves a large share of wet basements at a fraction of the cost.

What about the neighbor's water running onto my land?

Water law varies substantially by state. A curtain drain uphill of the house at $1,500 to $6,000 intercepts it without a dispute, which is usually faster than resolving one.