Outside service area sewer can be obtained either by annexation to a sanitation district or zone or through an Outside Service Area Agreement (OSAA, or “sewer agreement”) with a sanitation district or zone. The County will determine which method to use, depending upon the location of the property. A request for outside service area sewer service must be approved by the Board of Directors of a sanitation district or zone; the Permit Sonoma does not approve the sewer service request.
Annexation is used when property is located inside the urban service area of a sanitation district or zone. Property annexed to a sanitation district or zone may be developed to the full extent allowed by zoning regulations, including construction of new buildings that require sewer service.
When property is located outside of the urban service area of a sanitation district or zone, sewer is provided by a sewer agreement. Sewer agreements are typically written only for existing buildings Once connected to sewer, a building may be repaired, remodeled or replaced. Residential additions and new buildings that are not connected to sewer are also allowed. However, additional residential units (including second dwelling units) cannot be constructed and non-residential uses cannot be expanded.
Vacant property within the southern portion of the Sonoma Valley County Sanitation District Sphere of Influence may be connected to public sewer and developed for new residential use, depending on zoning, so long as the development does not exceed 1.0 Equivalent Single-family Dwelling (ESD) sewer connection assessments. Please consult with the Sanitation staff at Permit Sonoma for information regarding the location of your property and the availability of sewer service.
If a request for sewer service for a property with a septic system results in a sewer agreement, the applicant must demonstrate that the property has a failed septic system. The applicant is required to obtain a statement from a private Registered Environmental Health Specialist (REHS) or a Registered Civil Engineer (RCE), describing the condition of the existing system. The applicant is also required to apply with the Permit Sonoma Well & Septic Division for an inspection of the septic system.