Building on a hillside in Cotati: the local rules

Each rule below links to the section of the Cotati Municipal Code it was read from, with the code text one click away (checked October 2026). General information, not legal advice.

What Cotati's code says

Cotati code What Cotati's code adds
Soils or geology report	A preliminary geotechnical report is required; a final report may also be required, depending on the site and project design. Applies: Applies to a hillside development permit application. § 17.53.070 · code text A preliminary geotechnical report that identifies and proposes mitigation measures for any soils or geological problems that may affect site stability or structural integrity. Depending upon the site characteristics and project design, the review authority may also require a final geotechnical report.
Height on hillside lots	No structure may be taller than 24 feet. Applies: This is the general height limit for structures on hillside lots. § 17.53.050 · code text No structure shall exceed a height of twenty-four feet, measured in compliance with subsection (E)(1) of this section No more than 35 feet. Applies: Measured from the lowest point where the structure touches the grade to the highest point of the roof. § 17.53.050 · code text and shall not exceed a height of thirty-five feet, measured from the lowest elevation on the site where the structure touches the grade, to the highest point of the roof. No more than 16 feet above the highest ridgeline or hilltop point within 100 feet. Applies: A legal lot that existed before the ordinance, with no feasible building site except one that extends above the ridgeline. § 17.53.050 · code text proposed structures shall not exceed a height of sixteen feet above the highest point on the ridgeline or hilltop within one hundred feet of the proposed structure. No more than 6 feet. Applies: The vertical distance from the lowest point where the foundation meets grade to the lowest floor line. § 17.53.050 · code text shall not exceed six feet (see Figure 5-10). No more than 15 feet above grade. Applies: Applies to any single building wall on the downhill side of a house. § 17.53.050 · code text No single building wall on the downhill side of a house shall exceed fifteen feet in height above grade. No more than 6 feet above grade. Applies: Applies to the walking surface of a deck with visible underpinnings. § 17.53.050 · code text No portion of the walking surface of a deck with visible underpinnings shall exceed a height of six feet above grade.
When hillside rules apply	No new parcel may have an average slope of 20% or more. Applies: Applies to hillside subdivisions. Each new parcel needs a building site of at least 5,000 square feet with no slope of 10% or more. § 17.53.040 · code text With an overall average slope of twenty percent or more;

Who this affects

HomeownersContractorsDesigners

Frequently asked questions

What extra rules apply to a hillside lot in Cotati?

On hillside lots, 24 feet is the general height limit; height is also capped at 35 feet, measured from the lowest point touching grade.

Building on a hillside in Cotati

Key points

What Cotati's code says

Who this affects

Frequently asked questions

Ask about a specific Cotati property

More on building on your lot in Cotati