Want to add on to your property? What you need to know about ADUs in Stanislaus County

John Holland

In the Spotlight is a Modesto Bee series that digs into the high-profile local issues that readers care most about. Story idea? Email tips@modbee.com.

The Modesto Bee is looking into a promising approach to housing — second units added to single-family homes.

The new dwellings can occupy underused yard space or go over a garage. They can provide free living space for extended family members or be rented out for extra income.

A 2016 state law requires local governments to allow such projects in most areas zoned for housing. That includes the single-family parcels that are the vast majority of Stanislaus County’s real estate market.

This story lays out the basics on accessory dwelling units, as this option is formally known. We plan to later explore the costs and benefits, and to assess how far the idea has spread.

And we would love to hear from readers who have built ADUs. Send an email to jholland@modbee.com, with photos attached if you like.

You can call it an in-law unit or granny flat if ADU sounds too bureaucratic. Or a grandpa flat, for that matter. Whatever the name, we could end up with thousands of affordable units that blend nicely into neighborhoods.

ADU construction costs vary. A quick online search found a range of about $121,000 to $162,000 for a 400-square-foot studio apartment. Our research will include bank loans, which could be paid back through rental income, and government aid programs.

The Bee has made the housing shortage a key focus of its coverage. Some housing could be added in new multistory apartment buildings, such as Modesto’s plan for a few commercial strips. Some could be in more traditional subdivisions.

The need for various housing types is clear. As of late 2023, only 23% of the county’s households could afford to buy the median-priced house, at $465,000, the California Association of Realtors reported. The median cost was $1,750 a month for apartments and rental houses listed in early 2024, according to renthop. com.

A few basics about ADUs

This information is from websites for various state and local agencies, businesses and nonprofits:

  • The state requires cities and counties to permit ADUs up to 800 square feet. They can be as much as 1,200 square feet at local discretion.

  • The units can be two stories if they comply with local height limits.

  • ADUs must have kitchens, bathrooms and heating/cooling systems separate from the existing houses.

  • The owners must pay various fees for water, sewer and other public services. The total can be less than for a new single-family house because of the smaller footprint.

  • An architect must draw the plans. Several local governments provide them for free if the owner chooses one of several basic designs rather than customizing them. They are available in all unincorporated areas and in Modesto, Ceres, Turlock, Waterford, Oakdale and Riverbank.

A new apartment over an existing garage is among the suggestions for accessory dwelling units in Stanislaus County, California, in April 2024.
A new apartment over an existing garage is among the suggestions for accessory dwelling units in Stanislaus County, California, in April 2024.

How to apply in each locale

People interested in building ADUs can get permit details here:

Unincorporated areas are handled by Stanislaus County Planning and Community Development, www.stancounty.com. They include Salida, Empire, Denair, Keyes, Grayson and several other towns.

ADUs can be cheaper if they are prefabricated rather than erected on site. The Sacramento Bee just reported how one was lowered by crane into a backyard.

What do you want to know about life in Modesto? Ask our service journalism team your top-of-mind questions in the module below or email servicejournalists@modbee.com.

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