San Carlos, CA

Building a New Home/Home Additions

Are you thinking about adding on to your house, building a new house or accessory dwelling unit?  Follow the steps below:

  1. Visit our interactive zoning map and search for the site address. A pop-up window will show the zoning designation with a link to the development standards.
  2. Research the zoning information for the property. Most single-family residences are in the RS-6 or RS-3 zoning districts. If your home is not within one of these districts, please email us for more information and requirements.
  3. Work with a design professional to review development and design standards. If you have any questions, please email our Planning Division at Or you can make an appointment to visit a planner during our counter hours by emailing us at
  4. Work with your design professional to prepare plans. Use the Single-Family Residential Packet to prepare your submittal. Applications will not be accepted unless they include these minimum requirements to begin a review.
  5. Determine whether your proposal will be reviewed by our Building Division, Planning Division or the Residential Design Review Committee (RDRC).
    • First floor additions of less than 400 square feet with a resulting house square footage of 3,000 sq. ft. or less (including garage) can be submitted directly to our Building Division.
    • Any other additions, with a resulting house square footage of 3,000 sq. ft. or less (including garage) can be reviewed by our Planning Division.
    • Additions of any size where the resulting house square footage is more than 3,000 sq. ft. require review by the RDRC. Please note if your lot is larger than 7,500 sq. ft. your threshold may be higher. Please email us for more details.
    • New homes require review by the RDRC.
    • If your project only consists of an Accessory Dwelling Unit (ADU), you can submit directly to our Building Division. However, to ensure that all requirements have been met, please check with our Planning Division before you submit. If your project is an ADU plus an addition or new house, you will need to submit to our Planning Division.
  6. Refer to the Online Application Submittal Handout to submit your application, complete plans, supplemental materials and fees or email to make an appointment to submit your project during our counter hours.

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