Monterey County ADU Resource Guide


Ready to start planning your ADU? Here are some local resources that can help.

Water Availability

If you’re located on the peninsula, water availability may be a challenge. The cities of Seaside and Pacific Grove currently do have water credits available for purchase. Several areas of the Peninsula have water availability issues. However, it may still be possible that you have water credits available or existing water credits to accommodate certain planned ADUs. Click here for a form from the Monterey Peninsula Water Management District (MPWMD) which can help to calculate the amount of water that is needed for your ADU or find other useful forms on MPWMD’s website. Learn more about purchasing credits from the City of Pacific Grove. For more information on how to move around water credits in your home, read this guide and look at this list of rules from the MPWMD. Contact the Monterey Peninsula Water Management District for more questions at (831) 658-5601.

Water Safety

If you live in unincorporated North County areas, you may have issues with water quality that could stand in the way of constructing an ADU. To find out more, contact the county at (831) 755-5025.


One of the biggest barriers for most homeowners is financing their ADU. There are currently no ADU specific loan products available in Monterey County. However, conventional financing options may be an option for you to finance your ADU.

Public Plans

The City of Seaside has developed pre-approved plans for Seaside homeowners to use. Other homeowners in the county are welcome to use the plans to save cost on designing a detached ADU. Keep in mind that they are not plan check pre-approved except within the boundaries of the City of Seaside.

Prefabricated Options

United Way of Monterey County, with the help of our partners, has created a list of local building companies creating prefabricated ADUs. Building your ADU prefabricated can save on construction costs.

Local Code And State Law

Some restrictions may still apply to your property; however, many local limits have been eliminated as of January 1, 2020. Learn more about the local city code for your area and the 2020 state law information



ADU Workshop Recordings

2021 ADU Conference

Homeowners, builders, finance partners, and affordable housing advocates convened for a virtual ADU Conference to promote infill housing in Monterey County and to equip homeowners with the tools they need to pursue a financially feasible and affordable ADU project.

The conference covered the following topics:

  •  ADU Policy: CA HCD, MBEP and UWMC will present on ADU policy, including presentation of a guide to assist homeowners and city staff in navigating ADU State law
  • Prefabricated ADUs: What are the benefits? Local prefab vendors will provide locally available products, how-to instruction and tips, and present a cost comparison and sample budget to show how you can save on your ADU project
  • ADU Financing: Presentation from regional experts on ADU financing about available products and best practices




Seaside ADU Workshop

Join the City of Seaside and United Way Monterey County for a workshop designed for Seaside homeowners interested in starting an ADU project. In this workshop, participants will learn how to navigate their ADU project along with the City of Seaside - including permitting, using pre-approved plans, hiring design and building professionals, financing, and what resources are available to Seaside homeowners. This workshop will feature a presentation and a Q&A after the presentation for homeowners to ask more specific questions to our presenters about their projects.





Monterey County ADU Conference

UWMC’s ADU Advisory Group and AIA Architects gathered for a virtual ADU Conference between September 16th and September 18th. The goal of the conference was to promote infill housing in Monterey County and equip stakeholders with the tools they need to execute ADU projects. The virtual conference featured Kol Peterson, an ADU expert and author of Backdoor Revolution: The Definitive Guide to ADU Development.



ADU Literature Review (2019): Highlights the ADU policies within Monterey County and includes policy recommendations and case studies.

ADU White Paper: Strengthening ADU Policies and Practices in Monterey County (2021)

City and County Policy:
State Law Updates 2020

Effective January 1, 2020:

  • Senate Bill 13: Reduces and/or eliminates development impact fees for ADUs, prohibits owner occupancy requirement, further reduces parking requirements, and lowers jurisdiction’s ADU application approval time to 60 days.
  • Assembly Bill 881: Prohibits minimum lot size requirements, limits local discretion on min. and max sizes for units, and allows for an 800 sq. ft. ADU to be developed on single-family lot, regardless of lot coverage, floor area ratio, or setback requirements.
  • Senate Bill 68: Allows both an ADU and a JADU on the same single-family lot.
  • Assembly Bill 670: Homeowner associations (HOAs) and common interest developments (CIDs) must now allow ADUs within their developments.

Effective January 1, 2019:

  • Senate Bill 1226: Applies to unpermitted/illegal ADUs (California Legislative Information, 2018)
  • Assembly Bill 494: Further reduces parking requirements (California Legislative Information, 2017)

Effective January 1, 2017:

  • Senate Bill 1069: Reduces parking requirements, utility fee reductions, and streamlines the approval process. (California Legislative Information, 2016)
  • Assembly Bill 2299: Streamlines approval process for local governments (California Legislative Information, 2016)
  • Assembly Bill 2406: Applies to junior accessory dwelling units (JADU) ordinances (California Legislative Information, 2016)(California Department of Housing and Community Development, n.d.)
Additional Resources:
  1. California Department of Housing and Community Development (HCD) Accessory Dwelling Units
  2. LA MÁS
  3. Santa Cruz City and County (Santa Cruz Sentinel. Nicholas Ibarra. Santa Cruz County Offers Amnesty to Unpermitted Homes.)
  4. Santa Cruz County ADUs
  5. Housing Trust Silicon Valley: Small Homes BIG IMPACT Pilot program that offers free educational workshops and financial assistance to homeowners seeking to build an ADU.
  6. Lessons Learned from Portland, Seattle, and Vancouver. Report discusses the remaining barriers facing homeowners even when removing policy barriers. Interesting ideas to spur the market for ADUs.