Maximum Permitted Grades

Maximum Permitted Grade 

No road or driveway shall have a maximum grade in excess of twenty percent (20%). (Sonoma County Code Section 13-31(a); Public Resources Code4290; California Code of Regulations Title 14- Natural Resources, Division 1.5, Chapter 7, Subchapter 2, Sec 1720.03)

Grades in excess of 20% percent are non negotiable.

No road or driveway shall have a maximum grade in excess of fifteen percent (15%), without the approval of the County Fire Chief. (Sonoma County Code Section 13-31(a); Public Resources Code 4290; California Code of Regulations Title 14- Natural Resources, Division 1.5, Chapter 7, Subchapter 2, Sec 1720.03; California Fire Code Sec. 503.2.7)

The County Fire Chief may approve an application for an exception or mitigated practice for a road or driveway which include grades over fifteen percent (15%) and up to twenty percent (20%) for distances not exceeding three hundred feet (300') within any one thousand feet (1,000') of road or driveway. In granting such approval, the County Fire Chief shall require such additional fire protection measures under Section 13-63 as he or she deems necessary to mitigate access constraints. (Sonoma County Code Section 13-31(a); Public Resources Code 4290; California Code of Regulations Title 14- Natural Resources, Division 1.5, Chapter 7, Subchapter 2, Sec 1720.03)

Applications for an exception or mitigated practice shall be made in writing by an applicant for development or the applicant's authorized representative.

The application shall:

• State the specific section or sections of this article for which an exception or mitigated practice is proposed
• State the material facts supporting the contention of the applicant
• Describe the details of the exception or mitigated practice proposed
• Include a map showing the proposed location and setting of the exception or mitigated practice.

The burden of proving that a proposed exception or mitigated practice is warranted shall be on the applicant.
(Sonoma County Code Section 13-23(c); Public Resources Code4290; California Code of Regulations Title 14- Natural Resources, Division 1.5, Chapter 7, Subchapter 2, Sec 1720.03)

There is a minimum two-hour Fire Marshal Review fee for the review and consideration of an application for an exception or mitigated practice. (California Government Code Sec 66014)

Common Mitigation Practices for Access

Application for access mitigation shall take into consideration the list of appropriate additional and alternate fire protection methods. In most situations Access is mitigated with access.

Examples are,

• Additional width
• Additional turnouts
• Additional turnarounds
• Alternate surfacing
• Additional water supplies above the minimums required by code

Most common proposed additional and alternates for grades up to 20 percent is additional width over 12 feet and additional turnarounds when not required by code.