Pre-approved ADU plans in San Diego: free plans and the 30-day review

Pre-approved ADU plans in California

Assembly Bill 1332 (2023) added Government Code section 65852.27. It required every city and county to create a program for pre-approving ADU plans by January 1, 2025. The key rules:

• 30-day decision. A city must approve or deny an application for a detached ADU within 30 days if it uses a plan the city pre-approved, or a plan identical to one it approved during the current triennial code cycle. A custom ADU application gets up to 60 days.
• Anyone can submit plans. An architect, builder or nonprofit can ask a city to pre-approve its design, and the city can't restrict who submits.
• Plans go online. Approved plans must be posted on the city's website with the designer's contact information.
• Same fees. A city may charge the same permit fees it would charge for a comparable ADU.

The faster clock applies only to detached ADUs. For the rest of the state rules, see our guide to California ADU laws.

Pre-approved ADU plans in San Diego County

Programs fall into two types. Some governments paid to design plans and give them away. Others list plans that private designers submitted, which you license from the designer.

Sources: each jurisdiction's program page. Program details change, so confirm with the permit office before you commit to a plan.

County of San Diego ADU plans

The County's plans are the most widely used in the region. They're free, designed to work anywhere in the unincorporated county, and come in six ADU sizes: three at 1,200 sq ft, and one each at 1,000, 800 and 600 sq ft. The County also offers two larger plans for a single-family home only. The current plan sheets reference the 2025 California codes. The City of San Diego and the City of Santee both accept them.

City of San Diego

The City of San Diego doesn't publish its own plan set. It accepts the County of San Diego standard plans, the City of Chula Vista standard plans and the City of Encinitas permit-ready plans, with a 30-day review. The plan still has to meet the San Diego Municipal Code, and you contact the plan provider about any license cost. Designers can also apply to have their own plans pre-approved for use by others.

Chula Vista pre-approved ADU plans

Chula Vista's standard ADU plans come from design professionals the city approves. To use one, you contract with the designer responsible for that plan set. The city says applicants pay roughly $1,000 less in plan review fees than for a full custom submittal.

Encinitas PRADU

Encinitas's Permit-Ready ADU (PRADU) program offers plans for detached units from a studio to three bedrooms. Because the City of San Diego and Santee accept them, Encinitas plans reach well beyond Encinitas.

Escondido PAADU

Escondido offers four free plans: a 484 sq ft studio or one-bedroom, a 644 sq ft two-bedroom, an 851 sq ft two-bedroom with two baths, and a 1,000 sq ft unit with two or three bedrooms and two baths. They're for new, detached, single-story ADUs only, not conversions, attached units, second stories or prefab units.

Free ADU plans vs. licensed plans

“Pre-approved” doesn't always mean free. The County of San Diego and Escondido give their plans away. Carlsbad's permit-ready plans are free to download. But in Chula Vista you contract with the plan's designer, in Poway the architect must authorize use of the plans and may charge for it, and in Oceanside you buy the package from the plan vendor. When you use an accepted plan in the City of San Diego, the city tells you to ask the provider what the license costs.

A licensed plan can still be worth it. The designer usually knows the plan's quirks and can complete the site-specific pieces for you.

What pre-approval covers, and what it doesn't

A pre-approved plan has been checked against the building code for the structure itself. It hasn't been checked against your lot. The County calls its plans “approximately 85% complete.” Across the programs, you still need:

Sources: County checklist PDS 607 and city program pages. Zoning still applies too: the ADU has to meet your city's setback, height and lot rules.

The plan also doesn't cover the foundation conditions on your site. A plan assumes a certain soil bearing strength. Poway, for example, requires a soils report showing your site meets the strength the plan was designed for. A sloped lot, poor soil or a long utility run adds cost no matter whose plan you use.

Changing a pre-approved plan

The speed comes from using the plan as drawn. Change too much and you're back to a custom review.

• Escondido: you can't change the size, shape or configuration, but you can change select features, including windows and doors.
• San Marcos: no alterations to city plans are considered. A customized design goes through the standard ADU permit.
• Carlsbad: modified plans aren't eligible for expedited processing.
• State law: the 30-day clock applies to a pre-approved plan or one identical to a plan already approved in the current code cycle.

How much you save

The savings are real but modest. Snap ADU, a San Diego builder, estimates (April 2026):

Source: Snap ADU, a builder, not an official figure. Because construction is most of the budget, the plan choice matters less than the builder. Snap ADU also notes that overall timelines often end up close to a custom design once site work and corrections are counted. In Chula Vista, add the roughly $1,000 plan review discount.

When a pre-approved plan fits

A pre-approved plan works best when:

• Your lot is fairly flat with room for a single-story detached unit.
• One of the published sizes matches what you want. Our guide to ADU floor plans and sizes shows what fits at each size.
• You don't need a garage conversion, attached unit or second story. Those need custom plans; see garage conversion ADUs and two-story ADUs.

Either way, you still need a licensed builder. Compare verified ADU builders in San Diego, check a contractor's license, and read how to hire an ADU contractor. For the permit steps that follow, see our San Diego ADU permit guide.

Common questions