On a hillside lot, the permit starts in the ground. Before Building and Safety signs off on your plans, a soils engineer and an engineering geologist have to say the slope can carry the work, and your plans have to show what they recommend.
After that it is paperwork in a set order. I prepare the plans and file and pull the permit myself, so this is the order I walk through on a hillside job, for the City of Calabasas and for unincorporated LA County.
Find out who has your lot before anything is drawn.
Inside Calabasas city limits, the city reviews it: Planning for the hillside and ridgeline rules, Building and Safety for plan check.
Outside city limits, in unincorporated LA County (Topanga is one example), it goes through LA County Public Works Building and Safety, at the Calabasas-Malibu district office on Agoura Road. Same canyons, different rulebook.
This is the document the whole job hangs on.
In Calabasas, the Building and Safety submittal checklist lists a geology/soils report with the plans and structural calcs. A retaining wall over 4 feet needs a soils report that backs up its design numbers, and it gets its own permit.
In LA County, the plan checker decides if your job goes to the county’s Geotechnical and Materials Engineering Division (GMED). The report has to be signed and stamped by a California Certified Engineering Geologist and by a Geotechnical Engineer, or a Civil Engineer with geotechnical experience.
A few county rules catch people out:
A licensed third party does the soils and geology report. I don’t write it. I design around it. The foundation type, the retaining walls and sometimes where the house can sit all come out of that report, so it should be in hand before the design is final.
Calabasas has its own hillside standards in the Development Code, Section 17.20.150. They apply to any site with a natural slope over 10 percent, or with a ridgeline on it.
Two more lines on the map:
In Calabasas, Section 17.52.030 of the Development Code requires a grading permit for any excavation that isn’t exempt. The city’s application asks for your cut, fill, over-excavation and import/export numbers in cubic yards, and the names and licence numbers of the civil engineer and the geologist or geotechnical engineer. Once grading is approved, the site can get its building permits.
In LA County, the referral sheet lists every agency that has to approve your job before the permit is issued. All of those approvals go in at least 48 hours before the permit is issued. On some jobs the county also requires rough grade approval before it will issue the building permit.
Once you dig, the county’s grading guide sets the rules:
A 2023 letter from the LA County Fire Department says all of Calabasas is a High or Very High Fire Hazard Severity Zone. The city says those properties may fall under Chapter 7A of the California Building Code (wildfire-resistant construction).
In a Fire Hazard Severity Zone, LA County Fire needs an approved Fuel Modification Plan before the building permit for:
After you move in, brush clearance is yearly: out to 100 feet under the county’s 2023 notice, and up to 200 feet in extra hazardous areas.
None of these agencies publishes a fixed timeline for a hillside permit, and I won’t make one up. It depends on how many agencies are on your referral sheet, how many rounds of corrections each one sends back, and whether the soils report has to be redone. On county jobs, the referral sheet itself says the review clock stops while an outside agency’s approval is outstanding.
What shortens it is a first submittal where the soils report, grading plan and architectural plans all agree.
Vision In Design Inc is a design-build company. If you call me for an estimate, I can’t give you an honest number until I know what you want to build. So I do a preliminary design first. Once you like the design, I give you the estimate.
If you go ahead, I design the project, prepare all the plans, and file and pull the building permit. The third-party work is separate from mine: structural engineering, surveying, the soil and geology report if one is required, and the city or county permit fees. Then we build what was drawn and permitted.
More on architectural design and permit drawings and on hillside construction. If you have a sloped lot in Calabasas or the hills around it, call me at (818) 645-1129. Have the address ready, and the soils report if you already have one. ## FAQ
Plan on it. The city’s submittal checklist lists a geology/soils report, and retaining walls over 4 feet need one. Ask the city counter what your scope needs.
LA County’s grading guide splits the job. The soils engineer watches the ground get prepared and tests that the fill is compacted. The engineering geologist inspects the bedrock as it is dug and checks it matches the approved report.
For LA County review, one year from submittal. After that, the consultants write an update.
In LA County, the geotechnical manual calls out decks and pools near slopes for slope stability review, and pools must meet the code setback or a bigger one the geotechnical engineer sets.
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