April 24, 2026 by B+W Engineering

When Does Your Los Angeles Project Need a Grading Plan? LADBS Requirements Explained

Q: When does LADBS require a grading plan in Los Angeles?

LADBS requires a grading plan when your property falls under the Hillside Ordinance, when you are building an ADU in a hillside zone, or when your project involves slope repairs, landslide repairs, mass grading, or subdivisions. The 500 cubic yard rule is the maximum allowable, not the trigger for requiring a plan.

Q: What is the 500 cubic yard rule for Los Angeles grading?

The Baseline Hillside Ordinance limits grading to 500 cubic yards plus 5% of your lot size. For example, on a 5,000 square foot lot, your maximum allowable grading would be 500 plus 250 cubic yards, totaling 750 cubic yards. If your project exceeds this, you need a Zoning Administrator Determination to exceed the allowance.

Q: Does an ADU in Los Angeles hillside zone need a grading plan?

Yes. ADUs in Los Angeles hillside zones require civil engineer sign-off and grading plans. Los Angeles City requires this for any ADU in areas where the natural slope exceeds 15% (the threshold that triggers the Hillside Area designation). The grading plan shows how the ADU site will be graded, how drainage is handled, and how you maintain pre-development flow patterns.

Q: What triggers the Hillside Ordinance in Los Angeles?

The Hillside Ordinance triggers when your property is in a designated Hillside Area. This is determined by slope - areas with natural slopes of 15% or greater based on USGS topographic data. The ordinance applies to hillside zones like R1-HCR, RS, RE, and RA zoned properties. Properties in these zones face grading limits, specific driveway requirements, and bonding requirements for grading.

Q: What is a grading bond and when is it required in LA?

A grading bond is required when your project involves 250 cubic yards or more of excavation or fill in a Hillside Grading Area. The bond amount is based on the volume of grading and protects the city if work is not completed properly. Your grading plans must be approved before the bond is posted.

Q: Can I skip the grading plan if my project is small?

If your project is flat, under 250 cubic yards of grading, and not in a hillside zone, you may be able to skip a full grading plan. But many projects that seem small end up triggering requirements during plan check. Getting a civil engineer involved early can save you surprises later.

LADBS requires grading plans for hillside properties, excavations over 500 cubic yards, and ADUs in hillside zones. Here is what triggers the requirement and how to navigate the process.

los-angeles grading-plans LADBS hillside ADU

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

Frequently Asked Questions

When does LADBS require a grading plan in Los Angeles?

What is the 500 cubic yard rule for Los Angeles grading?

Does an ADU in Los Angeles hillside zone need a grading plan?

What triggers the Hillside Ordinance in Los Angeles?

What is a grading bond and when is it required in LA?

Can I skip the grading plan if my project is small?

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