Contra Costa County and Residential Accessory Dwellings

Contra Costa County allows residential second units in certain zoning districts but the permitting process is downright terrifying here.

Before we get to the terrifying part, here are some of the development standards:

  • Lot Size. The minimum size of a lot with a primary residence and a second unit is six thousand square feet.
  • Second Unit Size. A second unit may not exceed 1,000 square feet, but for lots smaller than 10,000 square feet: Secondary dwellings may have a maximum floor area of 640 square feet.
  • Lot Coverage. In single-family residential districts, the second unit may not cause the maximum total structural lot coverage to exceed 40%

  • Living Provisions. A second unit must provide complete independent living facilities for one or more persons, including permanent provisions for living, sleeping, eating, cooking, and sanitation. The second unit may include one kitchen, living room, and dining room, and no more than two bathrooms and two bedrooms.

  • The additional parking space may be in tandem, or the additional space may be in the existing driveway if the additional space is outside the existing setback or side yard.

Those standards are all fine and quite in line with other regions.  The scary thing in Contra Costa County is the “Impact Fees”.   Fees for second unit permits will be in amounts established by the board of supervisors in the community development department’s fee schedule. Second unit866470ZBhixq_display_image2 (1)s are subject to all new development fees, including but not limited to development impact fees, park fees, and assessment district assessment allocations.  For Spring’s Casita in 2012, the summary of fees are approximately $24,821.  However, most of these fees go away if the cottage doesn’t have a kitchen.

  • Building Permit: $3,500
  • Lamorina Transportation:  $3,723
  • Waste Management: $80
  • Drainage Review: $175Fire Review: $215
  • Sewer Impact Fee $7,000 (Noted this is $600 if it is not a “Dwelling” unit)
  • Water $5,500 for a new meter

For many projects in Contra Costa the impact fees will actually add up to almost $50,000.  This is painful for everyone but we do have to agree that you do get quite a bit for those fees (3rd bore tunnel, summer recreation programs, insanely good schools).    Some people who don’t really need a full guest house with a kitchen but really just want an office or pool house with a shower will benefit greatly from making sure they get the permits for something that is not a “dwelling”.

Also, in January of this year the County adjusted their fees.  Verify with the Planning Division and zoning ordinance to confirm your requirements in your zoning district. Learn more about accessory dwellings by learning about our process.

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