How to Grade a Yard for Drainage

Water pooling against your foundation, soggy lawn patches, and a wet basement almost always trace back to one root cause: the ground slopes the wrong way. Grading is the practice of shaping the soil so water runs away from your house and off your lot instead of collecting where you don’t want it. It’s heavy but straightforward work, and fixing the grade is far cheaper than fixing the water damage it prevents. This guide covers how to measure your current slope, establish the right pitch, and move the dirt.

Understand the target slopes

There are two grades that matter. The foundation grade should fall at least 6 inches over the first 10 horizontal feet from the house (a 5% slope) — this is the single most important drainage rule and what most building codes specify. The general lawn grade across the rest of the yard should pitch at about 2%, or 1/4 inch of drop per foot, toward a place water can safely go: the street, a swale, a drainage easement, or a dry well. Keep finished soil at least 6-8 inches below siding and any wood, and never bury weep holes or cover the foundation’s damp-proofing.

Tools and materials

• Tools: shovel and garden rake, wheelbarrow, mason’s string, two or more stakes, a line level (or a 4-foot level and a long straight board), tape measure, hand tamper or plate compactor (rental for larger jobs), marking paint.
• Materials: fill/topsoil blend for building up grade (clay-loam packs better than sandy soil near the foundation), grass seed or sod to re-establish the lawn, and for drains: 4-inch perforated pipe, drainage gravel, and landscape fabric.

Step 1: Diagnose the problem and find the low spots

Walk the yard during or right after heavy rain and note where water pools and which way it flows. To measure precisely, drive a stake at the foundation and another 10 feet out. Tie a string between them, level it with the line level, then measure down from the string to the ground at the far stake. If that gap is less than 6 inches — or worse, the ground rises away from the house — you have a grading problem. Repeat across the yard to map high and low points before touching a shovel.

How to convert slope numbers

Slope gets quoted three ways and it helps to translate between them. A 2% slope means a 2-foot drop over 100 feet, which works out to about 1/4 inch of fall per running foot — the standard target for a lawn. A 5% slope is a 5-foot drop over 100 feet, or roughly 6 inches over 10 feet — the foundation rule. To check any stretch, measure the horizontal run and the vertical drop, divide drop by run, and multiply by 100 for the percentage. Carry these two numbers in your head as you work: 1/4 inch per foot across the open lawn, and 6 inches in the first 10 feet from the house. Everything else is just getting the dirt to match.

Step 2: Plan where the water will go

You can’t just push water off your foundation into a new puddle, or onto a neighbor’s lot (which can be illegal). Identify a legitimate outlet: the street gutter, a natural low area, a municipal storm easement, or a dry well/rain garden you’ll create. Plan a continuous downhill path from the foundation to that outlet. Call 811 before any significant digging to locate buried utilities. In many places it’s also a code violation to alter drainage in a way that harms adjacent properties, so if your only natural outlet runs toward a neighbor, look into a dry well or rain garden that holds and infiltrates the water on your own lot instead of shedding it next door.

Step 3: Build up the foundation grade

To correct a flat or negative slope near the house, add fill soil against the foundation and rake it out to taper down over those first 10 feet, achieving the 6-inch drop. Use a heavier clay-loam fill here, not sand or pure topsoil — sandy material erodes and lets water percolate straight down to the foundation. Add soil in 2-3 inch lifts and tamp each lift so the new grade doesn’t settle back into a low spot. Keep the final soil line 6-8 inches below siding. Check your slope with the string-and-line-level as you work.

Step 4: Smooth the general lawn grade

Fill low spots and knock down high spots to create a continuous gentle pitch (about 2%) toward your outlet. For larger areas, set a grid of stakes with strings marked at the target finished height and rake soil to meet them. Compact filled areas lightly so they don’t sink later, but leave the top inch or two loose and friable for seeding or sod. Re-check the slope across the whole run with your string line — water needs an unbroken downhill path, so even one flat spot will collect water.

Step 5: Add a swale or French drain if needed

When simple regrading isn’t enough — because the lot is flat, water comes from a neighboring property, or the soil drains poorly — add a drainage feature.

Swale

A swale is a shallow, gently sloped grassy channel that collects and carries surface water to the outlet. Dig a broad, saucer-shaped depression (not a steep ditch) pitched at about 1-2% along its length, then seed or sod it. It looks like part of the lawn and you can mow right over it.

French drain

For subsurface water, dig a trench about 6 inches wide and 18-24 inches deep, sloped at least 1% to the outlet. Line it with landscape fabric, add a few inches of gravel, lay a 4-inch perforated pipe (holes down), backfill with gravel, wrap the fabric over the top, and cap with soil and sod. The pipe gives trapped groundwater a fast path to daylight. The fabric wrap is what keeps the drain working for decades: it lets water pass but blocks the fine silt that would otherwise clog the gravel and pipe within a few years. Use a rigid perforated pipe rather than flexible corrugated tubing where you can — it holds its slope and resists crushing far better.

Dry well and rain garden

When there’s no downhill outlet at all, give the water somewhere to soak in. A dry well is a buried gravel-filled pit or perforated barrel that collects runoff (often from a downspout or the end of a French drain) and lets it percolate slowly into the surrounding soil; size it to your soil’s infiltration rate, which you can rough-test by filling a 12-inch hole with water and timing how fast it drops. A rain garden does the same job on the surface — a shallow planted depression set with deep-rooted natives that tolerate both wet and dry spells. Both keep stormwater on your property, which is increasingly what local stormwater rules require anyway.

Step 6: Re-establish the lawn and extend downspouts

Seed or lay sod over disturbed soil promptly — bare graded soil erodes in the next storm and undoes your work. Water it in to settle the grade. While you’re at it, extend downspouts at least 4-6 feet from the foundation (or tie them into the new drainage) so roof water lands well past your regraded zone rather than dumping right where the grade starts.

Common mistakes

• Using sand or loose topsoil near the foundation. It erodes and channels water down; use compacted clay-loam fill.
• Burying siding or weep holes. Keep soil 6-8 inches below siding.
• Creating a new puddle. Always grade to a real outlet, not just away from the house.
• Sending water onto a neighbor’s lot. Often illegal — route to a legitimate outlet.
• Leaving soil bare. Seed or sod immediately to lock in the new grade.

Maintenance and seasonal checks

Grading is mostly a one-time fix, but a few checks keep it working. After the first heavy rains, walk the regraded zone and confirm water is moving the way you intended; new fill can settle in the first season and reopen a low spot that needs a topping of soil and reseeding. Keep gutters clean and downspout extensions in place — clogged gutters dump concentrated water right at the foundation and overwhelm even a good grade. Each fall, clear leaves and debris from swale channels and French-drain outlets so they don’t dam up, and re-establish any thin turf on the slope, since bare soil on a pitch is the first place erosion starts.

When to call a professional

DIY regrading handles most surface and foundation slope problems, but some situations call for help. Large areas or deep cuts are faster and safer with a skid steer and an operator who can read laser grade. Water entering a finished basement, persistent foundation cracks, or a high water table point to issues a shovel won’t solve — those need a waterproofing or foundation specialist. And any time grading involves a steep slope, a retaining structure over a few feet, or rerouting drainage near a property line, a quick consult with a landscape contractor or your building department is cheaper than redoing the job or facing a complaint.

Cost ballpark

Minor DIY regrading with soil you already have can cost nearly nothing. A few yards of fill soil run about $30-$60 per cubic yard delivered; a typical foundation regrade uses 1-4 yards. Grass seed is cheap; sod runs roughly $0.40-$0.80 per square foot. A French drain adds about $5-$10 per linear foot in pipe, gravel, and fabric. Most DIY drainage corrections land between $0 and a few hundred dollars — against the thousands a chronically wet basement or foundation repair can cost.

Proper grading is the foundation for any hardscape, so settle the soil before you lay a paver patio. On steeper slopes, regrading often pairs with a retaining wall to hold the new grade in place. Find more drainage and landscaping projects in the Outdoor Living hub.