Prefab ADUs on the Central Coast
On the Central Coast, ADUs are now four in ten new homes — and rents near $3,000 a month make a backyard unit pay. We deliver an all-in prefab ADU from our Lathrop factory — permits, foundation, delivery and installation included — at one price fixed in writing.
Free lot check · zoning, fire & hydrant access · reply with a fixed price
Licensed builder · Our own factory in Lathrop, CA
Real homes we build, start to finish
Quick answer
ADUs in the Central Coast — key facts for 2026
Most Central Coast homeowners can add a detached ADU of at least 800 sq ft under state law, with no city impact fees up to 750 sq ft and no owner-occupancy rule. Bay Modular delivers a factory-built ADU all-in for $124,900–$271,900 — the same price anywhere in California, fixed in writing.
- Can I build an ADU on the Central Coast?
- Yes, on most lots with a house. State law guarantees at least an 800 sq ft detached ADU with 4-ft side and rear setbacks in every city.
- How long does a permit take?
- Cities must approve or deny a complete ADU application within 60 days (Gov. Code §66317). Coastal-zone lots may also need a coastal permit.
- What fees apply?
- No city impact fees up to 750 sq ft; school fees only above 500 sq ft. Utility connection fees depend on your lot.
- How much does a prefab ADU cost?
- Bay Modular: $124,900–$271,900 all-in for a rentable ADU, permits and installation included; $75,900 for a Backyard Studio home office.
- How many ADUs does the Central Coast build?
- 2,652 ADU permits in 2025 — 41% of all new homes in the five counties (HCD APR).
- What does an ADU rent for?
- Average asking rent was $2,954 in the Oxnard–Thousand Oaks–Ventura metro and $2,799 in the Salinas metro in August 2026 (Zillow).
Sources: HCD APR 2025 (Table A2), HCD ADU Handbook (2026), Zillow ZORI Aug 2026, HUD FY2027 FMR. Last reviewed October 2026.
Central Coast in numbers
Central Coast ADU permits rise every year
Up 61% since 2021 — and in 2025, 41% of all new homes in the five counties were ADUs.
ADU permits issued in the Central Coast
Source: California HCD Annual Progress Report data (Table A2), Monterey, San Luis Obispo, Santa Barbara, Santa Cruz and Ventura counties, permits issued per year. Percent = ADUs among all housing units permitted that year.
of all new homes permitted on the Central Coast in 2025 were ADUs
HCD APR data, 2025more ADU permits in 2025 than in 2021 (1,648 → 2,652)
HCD APR dataTop cities, 2025
Santa Maria479 ADUs
Oxnard244 ADUs
Salinas208 ADUs
Santa Barbara141 ADUs
Ventura136 ADUs
HCD APR data, permits issued in 2025Can I build in the Central Coast?
Most Central Coast lots with a house can add an ADU
State law sets minimum rights that every city in the Central Coast must honor. Here is what applies on most lots:
Every city must allow at least an 800 sq ft detached ADU, whatever its lot-coverage rules (Gov. Code §66321(b)(3)). All our models fit.
No more than 4 ft from side and rear lot lines; at least 16 ft of height for a detached ADU, 18 ft near transit (§66314(d)(7), §66321(b)(4)).
No parking required within ½ mile of transit, and no replacement parking when a garage is removed (§66322).
Cities can't require you to live on the property; they may require rentals of 30+ days (§66315).
No city impact fees for ADUs up to 750 sq ft (§66311.5); school fees apply only above 500 sq ft (Ed. Code §17620).
The city must approve or deny a complete application within 60 days (§66317).
Lots in the Coastal Zone may need a coastal development permit or waiver in addition to the building permit — we check this for your address.
Very high fire hazard severity zones (common in the Santa Barbara and Ventura foothills) can limit size and add fire-safety review.
Each city adds its own standards on top of state law — for example, Santa Barbara sets 850–1,200 sq ft limits by lot size. Open your city page for the details.
Based on the HCD ADU Handbook (2026) and Gov. Code §§66311.5, 66314, 66315, 66317, 66321, 66322. Not legal advice — local standards differ; see our city pages: Santa Maria, Santa Barbara, Ventura.
New in 2027: under AB 956 (Chapter 791, Statutes of 2026), from January 1, 2027 state law lets you build two detached ADUs on a lot with a single-family home, and HOA rules can’t block an ADU on a lot zoned to allow one.
Costs & fees in the Central Coast
What an ADU costs in the Central Coast
Same price as anywhere in California. Every model is 750 sq ft or less, so none pays city impact fees under state law; the only school fee — on the 2 Bedroom ADU — is included in the price.
| Model | All-in price | School fee | City impact fee |
|---|---|---|---|
| Backyard Studio120 sq ft · home office or guest studio, not a rentable ADU | $75,900 | $0 | $0 |
| Small Studio256 sq ft | $124,900 | $0 | $0 |
| Large Studio ADU320 sq ft | $154,900 | $0 | $0 |
| 1 Bedroom ADU480 sq ft | $214,900 | $0 | $0 |
| 2 Bedroom ADU640 sq ft | $271,900 | Included | $0 |
Sources: Gov. Code §66311.5; Ed. Code §17620. Comparison is general — every project differs.
Renting in the Central Coast
Renting out an ADU in the Central Coast
average asking rent for all homes in the Oxnard–Thousand Oaks–Ventura metro ($2,799 in the Salinas metro). HUD's 2027 fair rent for a 2-bedroom is $3,106 in Santa Maria-Santa Barbara and $2,424 in Oxnard-Thousand Oaks-Ventura.
Zillow Observed Rent Index (all homes, metro), Aug 2026 · HUD FY2027 2-bedroom Fair Market Rent by HUD area. ADU for rental incomeCities may require ADU rentals of 30 days or more (Gov. Code §66315); coastal cities such as Santa Barbara don't allow ADUs as short-term rentals — plan on long-term tenants.
New ADUs are generally exempt from local rent-control caps (Costa-Hawkins); check your city page for local rules.
A new ADU is exempt from California's statewide rent cap (AB 1482) for 15 years after its certificate of occupancy.
Same money, other options
Yearly income per dollar, before taxes and costs. An ADU wins because you already own the land. Full comparison →
Sources: Civil Code §1947.12; Gov. Code §66315. Comparison: HUD FY2027 2-bedroom Fair Market Rent, Santa Maria-Santa Barbara area ($3,106) × 12 ÷ $271,900; U.S. Treasury (Oct 6, 2026); FTSE Nareit (Sep 2026); FDIC (Sep 2026). Not legal or investment advice.
Permits in the Central Coast
How your ADU permit works — we handle it
Free lot check
Zoning, fire & flood maps, setbacks, access, sewer and power for your address.
Plans & submittal
Our HCD-approved plans plus your site plan, submitted to your city or county building department.
City review
Your city reviews the plans; we answer every correction for you.
Decision in 60 days
State law requires a decision on a complete application within 60 days. Your ADU is built in our factory meanwhile.
Install & move in
Delivered from our Lathrop factory and installed in about a week, inspected, then your Certificate of Occupancy.
* State law: the city must approve or deny a complete application within 60 days (Gov. Code §66317). Every lot differs.
Based on Gov. Code §66317 and the HCD ADU Handbook (2026). Review times vary by city — see our city pages for local details.
Why now
Start your Central Coast ADU with zero risk
Lock in launch pricing, see exactly what you get, and only decide once you have a fixed price for your lot.
All-in from $75,900 — everything included
- Backyard Studio (home office)$75,900All-in · fixed in writing
- Small Studio$124,900All-in · fixed in writing
- Large Studio ADU$154,900All-in · fixed in writing
- 1 Bedroom ADU$214,900All-in · fixed in writing
- 2 Bedroom ADU$271,900All-in · fixed in writing
Zero-risk start
- Free lot check & quoteNo obligation, no credit card.
- One fixed all-in priceDesign, permits, delivery and install — one number.
- HCD-approved plansState approval #1585366, financed and appraised like a home.
- 2-year warrantyOn materials and workmanship.
Visit our factory in Lathrop, CA and walk through a finished ADU.
Central Coast ADU questions
See all of California, open your city: Santa Maria, Santa Barbara, Ventura, or call (209) 214-6845.
How much does a prefab ADU cost on the Central Coast?
Bay Modular prices are the same anywhere in California: from $75,900 for a Backyard Studio (home office) and $124,900–$271,900 for a rentable ADU, all-in — design, permits and city fees, foundation, delivery, crane, utility hook-ups and final inspection, fixed in writing after a free lot check.
How many ADUs are built on the Central Coast?
2,652 ADU permits were issued across Monterey, San Luis Obispo, Santa Barbara, Santa Cruz and Ventura counties in 2025 (HCD APR data) — 41% of all new homes. Santa Maria led with 479, then Oxnard 244, Salinas 208, Santa Barbara 141 and Ventura 136.
What does an ADU rent for on the Central Coast?
Average asking rent was $2,954 in the Oxnard–Thousand Oaks–Ventura metro and $2,799 in the Salinas metro in August 2026 (Zillow). HUD's 2027 fair rent for a 2-bedroom is $3,106 in Santa Maria-Santa Barbara and $2,424 in Oxnard-Thousand Oaks-Ventura.
Do I need a coastal permit?
Only if your lot is in the Coastal Zone. Then the city may require a coastal development permit or waiver along with the building permit. We check this in the free lot check.
Can I build two ADUs on my lot?
From January 1, 2027, AB 956 lets you build two detached ADUs on a lot with a single-family home, and HOA rules can't block them where zoning allows a single-family home.
Do you deliver to my Central Coast city?
Yes — we build across the Central Coast from our factory in Lathrop, California. Send your address for a free lot check.
Free · no obligation
Can you build an ADU on your Central Coast lot?
Send your address. We'll check zoning, fire and flood maps, access and utilities, and send a price fixed in writing — permits included.
HCD-approved plans (#1585366) · 2-year warranty · factory in Lathrop, CA
Sources: California HCD Annual Progress Report data, Table A2 (Monterey, San Luis Obispo, Santa Barbara, Santa Cruz and Ventura counties, 2021–2025, updated Oct 2026); Zillow Observed Rent Index, metro areas (Aug 2026); HUD FY2027 Fair Market Rents; HCD ADU Handbook (2026); Gov. Code §§66311.5–66322; Ed. Code §17620; Civil Code §1947.12; AB 956 (Ch. 791, Stats. 2026). General information, not legal or investment advice. Updated October 2026.