Quick answer
Grading around a foundation is the shape and slope of the ground next to a house, set so that rain and melt water run away from the walls instead of toward them.
A slope that falls away from the wall is called positive grade. A slope that falls toward the wall is negative grade. Grade sets where surface water goes first, so it affects basements, crawl spaces and the soil under the footing.
Quick facts
The key facts about Grading Around a Foundation, with sources:
Key takeaways
- Grading is the slope of the ground at the wall. Good grade carries rain away from the foundation 1.
- Positive grade falls away from the house. Negative grade falls toward it and sends water to the wall.
- Published slope numbers differ. One county quotes an IRC fall of 6 inches in 10 feet. Other guides ask for more 245.
- Backfill next to a foundation settles, so a slope that was right at move-in can reverse 4.
- Regrading a few inches of surface soil is a homeowner task. Digging beside the wall is not.
- Grading does not replace drains or waterproofing. It is the first layer of water control.
What grading around a foundation means
Think of the ground around a house as a roof you walk on. A roof sheds rain because it slopes. The ground should do the same. Rain that lands near the wall should run out and away, not sit against the footing or soak down along the wall.
Texas guidance for builders says water must drain away from the house on all sides, and that nothing a subcontractor does should hinder that drainage 1. The same bulletin tells owners that changes to drainage flow can cause damage. Grade is therefore part of the house, not just the yard.
Our drainage and grading guide shows how grade works with gutters and drains. For the full water picture, read foundation drainage.
General information, not a diagnosis of your house
General information, not a diagnosis of your house. Soil, climate, lot shape and local code decide what slope is right for a given home.
How grade protects the wall
The main defense against water coming through a foundation is to keep the soil beside it from filling with water. A Department of Energy resource says the best defense is to prevent water from saturating the soil 3. Grade does that work first. It turns rain into runoff.
Saturated soil is heavy and pushes on a wall. The HUD structural guide warns that poor drainage may substantially raise the sideways load on a foundation wall if the soil becomes saturated 5.
Wet soil also swells or softens in some sites. The Colorado Geological Survey says drainage is extremely important because changes in soil moisture cause both swelling and shrinking 6.
Water that stands near the wall finds a path. It can go down the backfill to the footing, into a window well, or through a crack.
Moving it away early means less water for any later layer, such as a drain, to handle. See hydrostatic pressure on foundation walls for what saturated soil does to a wall.
House with ground sloping away from the wall, a gutter downspout and an extension carrying roof water away from the foundation. A dashed line shows the wrong slope toward the house for comparison.
Illustrative, not to scale, not a design. It shows ground falling away from the wall, a downspout extension, and the wrong-way slope that sends water to the wall.
Kinds of grade and surfaces near the wall
| Term | What it describes | What it does to water |
|---|---|---|
| Positive grade | Ground that falls away from the foundation | Sends runoff away from the wall 2 |
| Negative grade | Ground that falls toward the foundation | Sends runoff to the wall, where it can pond 4 |
| Flat grade | Ground with little or no slope at the wall | Lets water stand after rain; a low spot can form 6 |
| Swale | A shallow, wide channel in the ground | Carries water past or away from the house; code sets a slope within 10 feet of the wall 2 |
| Impervious surface | A slab, drive or patio next to the house | The IRC asks for a slope away from the building within 10 feet 23 |
| Permeable surface | Soil, mulch or lawn | Takes in some rain, so it needs slope too 3 |
Example: a spot check along one wall
The spot check below is an example of how an owner can measure grade with a level and a board, the method Kansas State describes 4. The numbers below are made up to show the steps, not a reading from any real house, and not a standard.
| Step | What you do | What you note |
|---|---|---|
| 1 | Lay a straight board from the wall out over the ground | Which way the board tilts |
| 2 | Set a level on the board and raise the outer end until level | The gap under the outer end |
| 3 | Measure that gap with a tape and note the board length | Rise over run, written down |
| 4 | Repeat at the corners and at each downspout | Which spots slope toward the wall |
| 5 | Compare to your local code and plans | Whether a closer look is needed |
Kansas State says a carpenter’s level, a 10-foot straight board and a tape are all you need to check that grade is adequate, and suggests checking when you do routine landscape work 4. Photograph low spots and date the photos.
Where grade matters most
Grade matters on every side, but a few spots take the most water. Low corners collect runoff from two roof planes. Spots below a downspout take a whole roof section.
Beds and planters next to the wall can hold water if they have curbs.
Window wells and basement stair wells are low points by design, and Kansas State says water that collects in a window well can easily enter the basement 4.
Grade also matters where the house meets a slab. Patios, walks and drives often settle and tilt toward the wall. Where that happens, water runs along the joint to the foundation. The code language quoted by one county asks that impervious surfaces within 10 feet of the foundation slope away from the building 2.
What good grade does for a house
What good grade does
What it cannot do
- Cannot stop groundwater that rises from below; see groundwater and foundation problems.
- Cannot work where the lot, a wall or a property line leaves no room to slope; drains or swales are then used 3.
- Cannot seal a crack or replace dampproofing or waterproofing.
- Wears away as backfill settles, so it needs repeat checks 4.
Where grading alone falls short
A good slope handles surface water. It does not handle water that comes from under the ground or from a leaking pipe.
A wall can still get wet if the water table is high or a hillside sends water through the soil.
Kansas State lists run-in, a high water table and flooding as the three main sources of basement water, and slope only addresses the first 4.
Retrofitting grade can also be hard. A DOE guide calls regrading after construction a difficult and expensive process, and lists footing drains, dampproofing and drains at sloped drives as alternatives when it cannot be done 3.
Where a lot is tight, the code exception quoted by Maricopa County sends water to drains or swales instead of a plain slope 2.
Grade can also fail in cold climates. The same DOE guide notes that melt water can refreeze into an ice ridge that pushes water back toward the wall 3.
Surface grade vs. drains
Grade moves water across the surface. A drain moves water under it. Many homes need both, and neither one is a substitute for the other.
What drives the cost of regrading
We do not print prices. Checking grade with a level costs nothing. Moving a small amount of soil by hand is mostly your time.
Larger work is driven by how much soil must move, how far it must be hauled, the need to protect trees, utilities and a slab, access for equipment, and whether drains or swales must be added.
If a plan calls for retaining walls, new drains or work near the footing, the project becomes a design job, and an engineer or licensed contractor should price it. Our cost guide explains how quotes are built, and the cost calculator helps frame the drivers.
How to check and correct grade
A general outline for surface checks and small corrections. It is not a design.
- Walk the house after a rain: Look for puddles within a few feet of the wall and for stains or splash marks on the foundation.
- Measure at several points: Use a level and straight board as in the example above 4.
- Find the cause of any low spot: A missing downspout extension, a settled backfill trench or a tilted walk are common ones.
- Add surface soil in thin layers: Where backfill has settled, Kansas State says to add fill to keep the slope away from the foundation 4. Keep the soil below the siding and below the top of the foundation wall.
- Do not dig beside the wall: Regrading means adding or shaping surface soil only.
- Re-check after the next heavy rain: New soil settles, so you may need a second pass.
Keeping the slope working
Grade changes slowly, so small habits matter.
- Check the slope when you do routine landscape work, and keep it when you replace plants 4.
- Add soil where settlement has flattened or reversed the slope 4.
- Keep grass, shrubs and sprinklers back from the wall; the Colorado guide asks for at least 5 feet in swelling soils 6.
- Keep flower bed edging from forming a dam that holds water at the wall.
- Fix a tilted walk or patio so it slopes away; ask a pro if it needs lifting.
- Keep gutters clear and downspouts extended so roof water does not undo the grade 7.
Risks and when to call a structural engineer
Wrong-way grade lets water reach the footing and the soil under it. On clay, that can mean swelling in wet spells and shrinking when the soil dries, and the movement is uneven.
On other soils, water can wash out or soften the ground. You cannot read that from the surface, so treat grade as a clue, not a diagnosis.
Do not dig a trench beside the foundation to fix drainage. Kansas State adds a caution for shrink-swell soils: do not fill and tightly compact cracks next to a basement wall when the soil is dry, because the soil may expand when it is wetted again and press on the wall 4.
Call a licensed structural engineer if cracks are widening or changing, if a wall bows or is displaced, if doors and windows stick along with new cracks, if corners separate, or if you doubt safety. Our engineer guide explains who to call.
Surface soil only
Add or shape soil on the surface. Do not dig next to the foundation, undercut a footing, or pile soil against siding. Drainage changes may also be subject to local rules, so ask your building department before moving water onto a neighbor’s land.
What codes say about grade
The IRC treats drainage in section R401.3. A Maricopa County planning document, dated 2008, quotes it as requiring that lots be graded to drain surface water away from foundation walls, with a fall of at least 6 inches within the first 10 feet.
Its exception lets a 5 percent slope apply where barriers prevent that, with water sent to drains or swales. It also asks for a 2 percent slope on swales and on impervious surfaces within 10 feet of the building 2.
The same document quotes section R404.1.6, which asks that concrete and masonry foundation walls rise above finished grade by at least 4 inches where masonry veneer is used and at least 6 inches elsewhere 2.
A DOE resource lists the 2009, 2012 and 2015 IRC for the 2 percent slope on impervious surfaces 3.
Other guides give other numbers. Kansas State calls about 1 inch per foot for 15 feet ideal, with at least 6 inches in 10 feet as a floor 4.
The HUD guide says finish grade should have a minimum of 1 inch of fall per foot for its empirical wall table 5.
ENERGY STAR, as quoted by DOE, uses 0.5 inch per foot for 10 feet on permeable surfaces 3.
Colorado’s 1978 guide says 12 inches of fall in 10 feet is often used as a guideline in swelling soils 6.
Edition and adoption
The Maricopa text predates later IRC editions and does not name its edition. Wording and exceptions change between editions, and states and cities amend them. Check the code your jurisdiction adopted.
Published slope guidance compared
| Source | What it says | Context |
|---|---|---|
| IRC R401.3 as quoted by Maricopa County (2008) | 6 inches of fall in the first 10 feet; 5 percent where barriers prevent it | Code text, edition not named 2 |
| DOE / PNNL guide quoting ENERGY STAR | 0.5 inch per foot for at least 10 feet on permeable surfaces | Voluntary program for new homes 3 |
| Kansas State Extension | About 1 inch per foot for 15 feet is ideal; at least 6 inches in 10 feet | Homeowner guide for dry basements 4 |
| HUD Residential Structural Design Guide (2017) | Minimum 1 inch of fall per foot of distance | Context: empirical foundation wall table 5 |
| Colorado Geological Survey (1978) | 12 inches of fall in 10 feet is often used as a guideline | Written for swelling soils 6 |
Grading myths
- Myth If the yard looks flat, the grade is fine.
- Reality Flat ground near a wall lets water stand. Codes and guides ask for a slope away from the wall 24.
- Myth Grade is set once and stays put.
- Reality Backfill settles and can reverse the slope over time 4.
- Myth More slope is always better.
- Reality The right slope depends on the site, and steep slopes bring erosion. Follow local code and plans.
- Myth Good grade means no drains are needed.
- Reality Grade handles surface water only. Groundwater and wall seepage need other tools 4.
- Myth Packing clay tight against the wall seals it.
- Reality On shrink-swell soil, tight fill can press on the wall when it is wetted 4.
Regional factors for grading
Swelling soils raise the stakes. Colorado’s Geological Survey says the most critical part of landscaping is the continual maintenance of properly designed slopes, because flattened slopes and uncorrected settlement cause ponding of rain, snowmelt and irrigation water 6.
Texas treats drainage, plant choice and sprinkling habits as the main ways to limit swings in soil moisture 1.
In cold regions, melt water and ice ridges change how water leaves the wall 3. Ask your building department what grade rule applies to your lot.
What to do with this
Start with a walk after rain and a few level readings. If water stands within a few feet of the wall, find the cause. If the wall is damp or cracks are new, log what you see with the water intrusion tool. For a serious or changing problem, see our foundation inspection page.
- If Ground slopes away and the wall stays dry
- Then Keep checking after storms and after any landscape work
- If Low spot or reversed slope near the wall
- Then Add thin layers of surface soil and extend downspouts
- If Wall is wet or damp even with good slope
- Then Look for groundwater or leaks; ask a qualified professional
- If New or widening cracks, bowing, sticking doors
- Then Call a licensed structural engineer; do not dig
Negative grade vs. positive grade
Negative grade means the ground falls toward the house. Positive grade means it falls away. That is the whole difference, and it decides where surface water goes. Kansas State describes how backfill settling can lower the soil and reverse the slope, so that water runs toward the foundation instead of away 4.
Negative grade is not always a design error. A new house can start with good slope and still end up with negative grade after the backfill settles.
HUD’s guide notes that common practice is to allow backfill to consolidate by adding extra fill, so that drainage away from the foundation stays adequate 5.
Heavy compaction at the surface can raise loads on the wall, so fill is usually placed with care 5.
You cannot judge grade by eye alone. A board and level give you a rise over a run you can write down.
If you find negative grade, the first step is to add thin layers of surface soil and extend downspouts, not to dig.
If water still reaches the wall, a professional can look at swales or drains.
Questions about Grading Around a Foundation
What is grading around a foundation?
It is the slope of the ground next to a house. Good grading makes surface water run away from the walls. Texas guidance for builders says water must drain away from the house on all sides 1. The slope comes from the lot design and from the soil placed around the foundation.
What is the difference between positive and negative grade?
Positive grade falls away from the house, so water runs off. Negative grade falls toward the house, so water runs to the wall. Backfill can settle and turn positive grade into negative grade over time 4. A level and a board can show which one you have.
How much slope should the ground have next to a house?
It depends on the source and the code. The IRC text quoted by Maricopa County asks for a fall of 6 inches in the first 10 feet 2. Kansas State calls about 1 inch per foot ideal 4. Your local code and plans decide the number for your house.
How do I check the grade around my house?
Kansas State says a carpenter’s level, a 10-foot straight board and a tape measure are enough 4. Lay the board from the wall, level it, and measure the gap. Check several spots, including corners and downspouts, and write the readings down with dates and photos.
Can I fix negative grade myself?
Small corrections on the surface are a common homeowner task. Add thin layers of soil where backfill has settled, and keep soil below the siding 4. Do not dig beside the foundation or undercut the footing. For bigger changes, ask a qualified professional and your building department.
How high should soil be against the foundation wall?
The soil should stay below the top of the wall. IRC R404.1.6, as quoted by Maricopa County, asks that concrete and masonry walls rise above finished grade by at least 4 inches with masonry veneer and at least 6 inches otherwise 2. Check your adopted edition.
Why does the ground sink next to my foundation?
Backfill is the soil placed against the wall after construction, and it often settles. Kansas State says it frequently settles over time, lowering the elevation and perhaps reversing the slope 4. Erosion and heavy downspout flow can also remove soil. Add fill in thin layers and fix the source of water.
Is grading enough to keep a basement dry?
Not always. Slope only handles water on the surface. Kansas State lists run-in, a high water table and flooding as three separate sources of basement water 4. A high water table or wall seepage may need drains. Read waterproofing vs. dampproofing for wall treatments.
Does grading matter on a slab foundation?
Yes. A slab sits close to grade, so water that pools at the edge can wet the soil under it. On shrink-swell clay, moisture changes at the edge of a slab are linked to uneven movement 6. Keep the slope away from the slab edge and keep drains and gutters working.
Do I need a permit to change the grade?
Sometimes. Local rules can cover grading, drainage onto neighbors’ land, and work in a flood zone. The Delaware guide on downspouts advises checking with city or county offices for flood rules and permits 7. Ask your building or public works office before any work beyond a small surface correction.
Sources
- Texas Department of Licensing and Regulation, IHB Technical Bulletin TB 10-01, Foundations on Expansive Soils – Residential (rev. Oct. 16, 2018), retrieved .
- Maricopa County Planning and Development Department, Building Elevation Plan Requirements (2008), quoting IRC R401.3 and R404.1.6, retrieved .
- U.S. DOE / Pacific Northwest National Laboratory, Building America Solution Center, Final Grade Slopes Away from Foundation, retrieved .
- Kansas State University Agricultural Experiment Station and Cooperative Extension Service, MF2809, Dry Basements and Crawl Spaces, retrieved .
- U.S. HUD Office of Policy Development and Research, Residential Structural Design Guide, 2nd ed. (Oct. 2017), retrieved .
- Colorado Geological Survey, Special Publication 11, Home Construction on Shrinking and Swelling Soils (Holtz and Hart, 1978), retrieved .
- Delaware DNREC, I-ADAPT Exterior Adaptation, Extend Downspouts, retrieved .
Expert review
Written by the HyreFoundation Research team. Not yet reviewed by an outside expert. We say so rather than imply a review that has not happened; see our editorial policy.
How the numbers were checked: Facts were checked against the Texas TDLR, Maricopa County, DOE/PNNL, Kansas State, HUD, Colorado Geological Survey and Delaware DNREC documents listed above, retrieved 2026-10-14.
IRC section numbers come from a 2008 county document that does not name its edition and may differ by edition. No structural engineer has reviewed this page.
Suggest a correction. We fix errors and say what changed.