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ENC-006 Required Driveway Entrance Upgrades

Permit and Resource Management Department Banner 750

Version 07/09/2020

Identify the building activities that require an existing driveway entrance(s) to be upgraded to meet current County standards prior to obtaining a building permit. This shall not apply to any use that requires a discretionary permit pursuant to the County's Zoning Code. Such uses shall be reviewed on a case-by-case basis to determine whether a driveway entrance upgrade is required.


Many existing driveway entrances located throughout Sonoma County fail to meet current Transportation and Public Works Department (DTPW) standards. Some common issues associated with existing driveway entrances are the lack of adequate sight distance, the lack of adequate drainage facilities, the lack of adequate entrance curves, or the lack of adequate surfacing. All of these issues impact ingress and egress to a property and the flow of traffic along the County road serving the entrance.

Although these existing entrances may have been installed prior to permit requirements, there are public safety benefits to upgrading existing driveway entrances to current DTPW standards. As such, existing driveway entrances are reviewed by Permit Sonoma Staff when the property owners or their agents apply for building permits for structures that will be served by the existing driveway entrance(s).


The following building activities require the upgrade of any existing driveway entrance(s) that serve the structure for which the building activity is being applied:

  1. New or replacement Single Family Dwelling (SFD).
  2. New or replacement Guest House.
  3. Legalization of a new or replacement SFD or Guest House.


If it is determined that an entrance is required to be upgraded, a complete encroachment permit application will be required to be submitted prior to the issuance of the associated building permit and the driveway entrance(s) shall be upgraded prior to the associated building permit being finaled. Submittal of plans designed by a licensed civil or traffic engineer may be required.

Additional Information

In certain cases, site conditions may prevent an existing driveway entrance from being upgraded to comply with all of the current DTPW construction standards. In such cases, Permit Sonoma Staff are authorized to set special provisions to upgrade the driveway entrance in a manner that provides for the protection of public safety and the maximum possible compliance with DTPW standards. The special provisions may include, but are not limited to, the following:

  1. Relocation and/or removal of the existing driveway entrance.
  2. Removal and/or trimming of existing roadside trees and/or landscaping.
  3. Relocation and/or removal of additional existing structures (mailboxes, retaining walls, signs, etc.)
  4. Grading and/or further modification of existing roadside banks.