Why the finished grade decides the rest
Ground is shaped once and then lived with for decades. Paving, walks, landscape and the building itself follow the surface they were built on, so a grade that sends water the wrong way is paid for again every wet season. The California Building Code puts the rule at the wall: ground beside a foundation falls away at not less than 5 percent for the first 10 feet, or 2 percent where climate or soil conditions warrant the exception (CBC 1804.4), and where an obstruction or a lot line takes the room away, a swale sloped at least 2 percent inside those 10 feet stands in for it.
Fill behaves the way it was placed. Vegetation, topsoil and other unsuitable material come off first and the surface is scarified, organic matter and oversize rock stay out of the fill, and the material goes down in lifts, each compacted before the next to the density the owner's geotechnical report sets. Backfill at a foundation allows for later settlement, because a pad that settles takes the slab above it down too.
Earthwork at scale brings duties before a machine is unloaded. A grading permit comes from the building official unless the work is exempt, and the application states the quantities of cut and fill with a plan showing existing and finished contours. Disturb an acre, or an acre as part of a larger common plan, and the state construction stormwater programme asks for coverage, which the owner arranges with the pollution prevention plan before the start.
Grading is judged at the property line as well as at the building. Where a city has adopted the grading appendix, drainage across a boundary after the work may be no greater than before, excess or concentrated flow is kept on site or taken to an approved facility, and the ground at the discharge is protected against erosion. A regrade is therefore set out from the outlet backwards, not from the puddle outwards.
What lot grading includes
Existing levels are taken across the lot and at the walls, and the finished grade is drawn against the owner's approved plans: what comes off, what is brought in, where the falls run and which outlet each reaches. The quantities of cut and fill come out of that.
The dig area is delineated, the notification goes in, and the machine waits for every operator to mark its line or answer that it has none. Irrigation, site lighting and fuel lines are found the same way.
Vegetation, topsoil and soft material are stripped and hauled away, the exposed surface is scarified, and the cut is taken down to the level the plan sets.
Imported or reused material is spread in lifts and compacted as it goes, each one tested to the density the report calls for before the next is placed. Dust is watered down through the work.
The surface is trimmed to the falls: away from every wall, along the swales and into the inlets, with no flat corner left holding water.
Levels are re-shot against the plan, bare slopes are protected before the final inspection, and the grades, quantities and photographs go into the owner's record.
Fill is only as good as the lift below it. Material placed too thick, too wet or over ground that was never stripped will settle, and the slab, the paving and the falls built on top of it settle with it.
Where lot grading is needed
Warehouse yards
Tilt-up sites where trailers track the surface out of shape and the yard drains to a handful of inlets that sit high once the ground around them moves.
Retail pads
Pads cut for a new building or an expansion, where the grade has to serve the walks, the stalls and the entry doors as one surface.
Apartment and HOA commons
Lawns, courtyards and planted beds that have been built up over the years until the ground beside the buildings runs the wrong way.
Older low-lying housing
Streets laid before modern drainage, where finished floors sit close to or below the kerb and the ground beside the wall carries the water.
Unincorporated pockets
Properties on the agricultural edge with open ditches and no storm system, where the low spot in the yard is the only place rain collects.
Yards before paving
Subgrade brought to line and level, compacted and handed over so the base and the surface above it are laid on ground that will not move.
Questions about lot grading
Usually, and the building official decides. A grading permit is the normal route for earthwork, with exemptions for small self-contained work that does not endanger the public or affect adjoining property, and for excavation belonging to a building permit already issued. Whether the grading appendix applies at all depends on the ordinance that city or county has adopted.
The owner's geotechnical report where there is one, and the building official where the code sets the figure. Fill under a shallow foundation follows the approved report, and the grading appendix, where a city has adopted it, sets its own density and lift thickness. The results go into the record handed over at the end.
Only under the conditions the code sets. In a flood hazard area fill is placed, compacted and sloped so that it does not shift, slump or erode as flood water rises and falls, and in a floodway it is not approved without an engineering analysis showing no rise in the base flood level.
The dry months. Cut, fill and compaction want ground that is neither saturated nor running, and from November to March most of the year's rain falls. Working dry also means the dust controls run, so the site is pre-watered and haul roads are kept damp.
Not by more than before, which is the point of setting it out from the outlet. Additional or concentrated flow is held on the site or taken to an approved point rather than pushed across a boundary.
Lot grading by city
Lot grading is requested through the grading and drainage page for your city, which covers the ground, the permit office and where the water goes there.
Related grading and drainage services
