When Does LA Need a Grading Plan? LADBS Rules
LADBS requires grading plans for hillside properties, excavations over 500 cubic yards, and ADUs in hillside zones. Here's what triggers the requirement.
Most homeowners and contractors do not think about grading plans until LADBS rejects their project. By then, you have already spent money on architectural drawings and surveys. Then someone tells you that you need a civil engineer, and you have to backtrack.
Here is what actually triggers the grading plan requirement in Los Angeles, so you can plan accordingly.
What Is a Grading Plan Anyway
A grading plan shows the existing and proposed topography of your site. It tells LADBS how you are cutting into slopes, where you are filling, and how water drains across the property after construction. Without it, LADBS does not know if your project will cause drainage problems for you or your neighbors.
The Three Main Triggers
1. Hillside Slope Over 15%
If your property falls in a hillside zone, LADBS treats it differently. The Hillside Ordinance limits how much you can grade. Most hillside properties in Los Angeles areas like the Hollywood Hills, Los Angeles, and surrounding hillside neighborhoods fall under these rules. The 15% slope threshold is how LADBS designates hillside areas.
2. More Than 500 Cubic Yards of Grading
The rule is 500 cubic yards plus 5% of your lot size. A typical hillside lot might allow 500 to 800 cubic yards depending on size. If your basement excavation and driveway cut add up to more than this, you hit bonding requirements and additional approvals.
3. ADU in a Hillside Zone
Building an ADU in Los Angeles hillside zones requires civil engineer sign-off and grading plans. This is not optional. The grading plan must show how the ADU fits into the slope, how you handle drainage, and that you are not changing where water flows onto neighboring properties.
What Happens If You Skip It
LADBS catches it at plan check. Your architectural drawings get rejected, you pay additional fees for corrections, and your timeline stretches. We have seen contractors pour foundations and then find out they needed a grading plan. That is an expensive problem to fix.
How B+W Helps
We review the project early, identify what triggers grading requirements, and design accordingly. For hillside properties, we know how to work within the 500 cubic yard limit. For ADUs, we coordinate with your architect so the civil and structural engineering fit together without conflicts.
If you are planning a project in Los Angeles hillside areas, get us involved before you submit for permits. We can usually tell you within a day whether your project triggers grading requirements.
Have a project in Los Angeles that might need grading plans? Get in touch before you spend money on plans that will get rejected.
Related Blog Post: The Los Angeles Baseline Hillside Ordinance Explained
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