Quick Verdict
The 6-inches-in-10-feet grading rule is the common standard that the ground should fall at least 6 inches over the first 10 feet away from a foundation, which works out to about a 5 percent slope. It exists so surface and roof water drains away from the house instead of pooling against the wall. A grader hits it with grade stakes, string lines, shot elevations, and box-blade passes, then verifies the fall. The hard part is what to do when that 10-foot band runs into a fence, retaining wall, or the neighbor's lot. Here's the target, how the dig achieves it, and how Oregon ground complicates it.
What the Rule Actually Says
The widely used grading target, derived from the International Residential Code (IRC) that Oregon's codes build on, is that the finished grade should drop a minimum of 6 inches within the first 10 feet measured out from the foundation. That's roughly a 5 percent slope. The point is positive drainage: water has to head away from the building, not collect at the base of the wall where it can find its way into the crawlspace, slab, or basement.
| Distance from Foundation | Minimum Fall | Approx. Slope |
|---|---|---|
| First 10 feet | 6 inches | ~5 percent |
How a Grader Actually Hits the Target
Getting a consistent 5 percent fall isn't eyeballing it. The crew works to references:
- Set grade stakes around the foundation marked with cut/fill to finish grade.
- Shoot elevations with a laser or level to establish the foundation point and the point 10 feet out at the lower elevation.
- Pull string lines between stakes as a visual guide to the slope.
- Run box-blade passes to cut and shape the soil to the string/stake line.
- Check the fall with a level or grade tool to confirm it meets the target all the way around.
The skill is in producing a smooth, continuous slope, not a lumpy approximation. The grade staking and shooting grades covers the surveying side in detail.
When the 10-Foot Band Runs Out of Room
Here's the real-world problem: the rule assumes you have 10 clear feet to fall across. Often you don't. The 10-foot band can hit:
- A fence at the property line
- A retaining wall or hardscape
- The neighbor's lot (you can't grade water onto someone else's property or drain it onto theirs)
- A walkway, patio, or driveway at a fixed elevation
When the band runs out, you can't just keep falling. The fixes include:
- Swales: a shallow drainage channel that intercepts and carries water away within the available space.
- Drains: a catch basin or trench drain to collect water where you can't slope it far.
- Steeper short slope plus a hard surface: falling faster over a shorter distance, then a paved or drained surface.
The code generally allows alternatives where physical obstructions prevent the standard slope, but the water still has to be managed away from the foundation. That's where execution gets creative, and where sloping the grade away from your house covers the perimeter dig.
Oregon Ground Makes the Slope Matter More
- Willamette Valley clay sheds water poorly and stays wet, so the full slope is important to move surface water off before it soaks in against the wall.
- Hardpan and rock east of the Cascades can limit how deep you can cut to create the fall, sometimes forcing fill on the low side instead.
- Heavy winter rain statewide means the grade has to handle real volume, not just a token slope.
In wet Oregon, a grade that "kind of" slopes isn't enough, the consistent 5 percent fall earns its keep every winter.
What Regrading to the Rule Costs
Cost depends on whether it's a small targeted fix or a full perimeter regrade, how much soil moves, and how tight the access is. A short stretch is cheap; reshaping the entire perimeter is more.
Industry Baseline Range: Grading and leveling commonly runs $0.75 - $4.00+ per square foot, with a typical $500 - $1,500+ minimum callout on small residential regrades. These are industry baseline ranges for planning only -- actual pricing depends on site conditions, soil, access, depth, haul-off, and current market conditions. Get a site-specific quote.
Current Market Reality
Costs rise when the 10-foot band is blocked and the fix requires swales, drains, or imported fill, or when tight access forces hand-grading. A simple slope on an open yard is cheap; engineered drainage where there's no room to fall is not.
How to Check the Slope Yourself
You don't need survey gear to get a rough read on whether your grade meets the rule. A few low-tech checks tell you a lot before you call anyone:
- String-line and tape: drive a stake at the foundation and one 10 feet out. Tie a string at the same height on the foundation stake, run it level to the far stake (use a line level on the string), then measure down from the string to the ground at the far stake. If that gap is 6 inches or more, you have your fall.
- Carpenter's level on a board: set a long, straight board on the grade pointing away from the house, put a level on it, and shim the low end until it reads level. The amount you shimmed over the board's length tells you the slope.
- Watch where water goes: during a real Oregon downpour, go look. Water standing against the wall, a dark wet band on the siding, or a soft, soggy strip along the foundation all mean the grade is fighting you.
- Check the splash zone: if there's no gutter extension and downspouts dump right at the wall, even a good grade can be overwhelmed at that one spot.
These checks won't catch everything, but they tell you whether the slope is roughly right or clearly wrong before money gets spent.
Common Grading Mistakes That Undo the Rule
Plenty of yards have the right slope on paper and still send water at the house. The usual reasons:
- Sloping toward the house, not away. Sounds obvious, but a yard graded by eye, or settled over years, often falls back toward the foundation in spots.
- Burying the slope under mulch or beds. Piling soil, bark, or raised beds against the wall fills in the fall you paid for and can bridge above the siding line.
- A flat or reverse spot at one corner. Drainage is only as good as its worst point. One low corner that holds water defeats a good slope everywhere else.
- Ignoring the downspouts. A perfect grade still loses if roof water dumps at the wall instead of being carried past the 10-foot band.
- Grading over loose fill that settles. New fill that isn't compacted slumps over the first wet winter, and the slope flattens or reverses where it sinks.
Most of these are fixable, but they show why the rule is about the finished, settled, water-tested grade, not the number on the day the dirt was moved.
The Bottom Line
Aim for 6 inches of fall in the first 10 feet (about 5 percent) away from the foundation, hit it with stakes, string, shot grades, and box-blade passes, and use swales or drains where the band runs into a fence, wall, or neighbor. In wet Oregon, that slope is what keeps water out. For the full system, see the Oregon excavation contractor guide. Cojo grades to the rule across Oregon as part of our excavation services -- request a free estimate.