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Crizer Construction, Inc.

Los Osos · Planning guide

ADUs and guesthouses in Los Osos.

A place for visiting family. A home office. An independent dwelling. Start with the intended use, then check what the property can support.

County sources checked October 27, 2026.

Current County guidance

Los Osos has a specific ADU restriction.

The County currently prohibits ADUs in Los Osos under its coastal land use ordinance. Its Los Osos FAQ says the Board of Supervisors may revisit the restriction.

Read the County's Los Osos FAQ before planning an independent dwelling.

Two uses. Different rules.

Accessory dwelling unit
An ADU is a separate dwelling with facilities for independent living, including cooking. Countywide ADU information must be read alongside the specific restriction in Los Osos.
Guesthouse
A guesthouse provides sleeping or home-office space as an accessory to the main residence. The County's building FAQ excludes cooking and laundry facilities and separate rental use.

The County building permit FAQ explains the difference. The guesthouse page links to the applicable inland and coastal rules.

Site-plan illustration. A drawing for this guide.

What the allocation category means.

The allocation page lists accessory dwellings among the uses sharing a reserved 25 percent category. That category is not permission to build an ADU in Los Osos. The County's specific Los Osos restriction still applies.

For eligible uses in that category, complete requests are considered in arrival order between January 1 and July 1. After July 1, unused allocations are prioritized for the sewer service area. The County directs applicants in the reserved category to the next January 1.

Check the County's allocation calendar for the current process.

Planning a guesthouse.

A guesthouse follows a different permit path from an ADU. The County reviews the property's proposed use, coastal zoning, water and wastewater service, and any ground disturbance. Feasibility depends on the lot and the approvals it needs.

New foundations, utility trenches, grading, and construction access can affect habitat coverage. Confirm the project footprint and credit availability before setting a construction date.

What to bring to the first conversation.

  1. 01

    Start with the property

    Bring the address or parcel number, existing plans, and any County correspondence. Establish the lot's zoning and service area before choosing a layout.

  2. 02

    Describe how the space will be used

    Sleeping space for visiting family, a home office, and an independent rental dwelling have different requirements. Explain the intended kitchen, bathroom, and living arrangements at the first meeting.

  3. 03

    Check services and ground disturbance

    Gather water and wastewater service records. New foundations, utility trenches, grading, and construction access can affect the habitat review and the project footprint.

  4. 04

    Set the permit path before the drawings

    Confirm the applicable County approvals and habitat coverage. Then define the design and construction scope around a project the property can support.

Talk through the property and the intended use with Crizer. Our design, permit, and build process starts with the scope and the lot.

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Questions before you plan.

Can I build an ADU in Los Osos?
The County currently prohibits ADUs in Los Osos under its coastal land use ordinance. Its Los Osos FAQ says the Board of Supervisors may revisit the restriction.
Does the 25 percent allocation share allow an ADU in Los Osos?
The allocation page lists accessory dwellings among the uses sharing a reserved 25 percent category. That category is not permission to build an ADU in Los Osos. The County's specific Los Osos restriction still applies.
How is a guesthouse different from an ADU?
A guesthouse provides sleeping or home-office space as an accessory to the main residence. The County's building FAQ excludes cooking and laundry facilities and separate rental use.
Can I plan a guesthouse while habitat credits are limited?
The County reports that all of its available 2026 habitat mitigation credits are reserved. It is accepting no additional applications for those credits in 2026 and expects more credits in early 2027. It asks owners to check again in December 2026. New foundations, utility trenches, grading, and construction access can affect habitat coverage. Confirm the project footprint and credit availability before setting a construction date.

County sources

Checked October 27, 2026. Confirm the current requirements for your parcel with County Planning and Building.