Prefab ADUs in Santa Ana
In 2025, 82% of all new homes permitted in Santa Ana were ADUs — and rents here are up 40% since 2021. We deliver an all-in prefab ADU from our factory in Lathrop — permits, foundation, delivery and installation included — at one fixed price.
Free lot check · zoning, setbacks, utilities · reply with a fixed price
Licensed builder · Our own factory in Lathrop, CA
Real homes we build, start to finish
Quick answer
ADUs in Santa Ana — key facts for 2026
Most Santa Ana homeowners can add a detached ADU of up to 1,000 sq ft, with no impact fees under 750 sq ft and no parking near transit or for a studio. Bay Modular delivers a factory-built ADU all-in for $124,900–$271,900 — the same price anywhere in California.
- Can I build an ADU in Santa Ana?
- Yes, on most residential lots with a house. Santa Ana allows a detached ADU up to 1,000 sq ft and 20 ft (two stories), with 4-ft side and rear setbacks.
- How long does a Santa Ana ADU permit take?
- ADUs that meet Sec. 41-194 are approved ministerially; state law requires a decision within 60 days of a complete application.
- What fees does Santa Ana charge?
- No impact fees under 750 sq ft (state law). Santa Ana Unified's school fee applies only to ADUs over 500 sq ft; permit fees apply.
- How much does a prefab ADU cost in Santa Ana?
- Bay Modular: $124,900–$271,900 all-in, the same price as anywhere in California, permits and installation included.
- How many ADUs does Santa Ana build?
- 258 ADU permits in 2025 — 82% of all new homes permitted in the city — and 955 since 2021.
- What does an ADU rent for in Santa Ana?
- Average asking rent in Santa Ana was $2,812 a month in August 2026 (Zillow), up 40% since January 2021.
Sources: HCD APR 2025, Santa Ana Zoning Code Sec. 41-194 and the City’s ADU/JADU Development Standards, Zillow ZORI Aug 2026. Last reviewed October 2026.
Santa Ana in numbers
Most new homes in Santa Ana are now ADUs
Santa Ana issued 955 ADU permits from 2021 to 2025 — and in 2025, 258 of 316 new homes permitted (82%) were ADUs.
ADU permits issued in the City of Santa Ana
Source: California HCD Annual Progress Report data (Table A2), City of Santa Ana, permits issued per year. Percent = ADUs among all housing units permitted in the city that year.
average Santa Ana asking rent since January 2021 ($2,007 → $2,812)
Zillow Observed Rent Index, City of Santa Ana, Aug 2026ADU permits issued in Santa Ana in five years (2021–2025)
HCD APR data, 2021–2025Can I build in Santa Ana?
Most Santa Ana lots with a house can add an ADU
Santa Ana’s ADU rules (Zoning Code Sec. 41-194) follow state law with a few local details. Here is what matters for most homeowners:
A detached ADU can be up to 1,000 sq ft — all our models fit.
4 ft from side and rear lot lines; up to 20 ft or two stories for a detached ADU.
One space for a new unit — but none within half a mile of transit, for a studio, near car share, in a historic district or inside an existing building.
An ADU and a JADU on a single-family lot under state law.
ADUs can be rented for 30 days or more — short-term vacation rentals aren't allowed.
Santa Ana offers 10 City pre-approved ADU plans — we use our own HCD-approved designs.
Based on Santa Ana Zoning Code Sec. 41-194 and the City’s ADU/JADU Development Standards page. Not legal advice — rules depend on your exact lot. More in our ADU guides.
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 Santa Ana
What an ADU costs in Santa Ana
Same all-in price as anywhere in California. Our models are all under 750 sq ft, so none pays impact fees — and four of five pay no school fees.
| Model | All-in price | School fees | City impact fees |
|---|---|---|---|
| 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 | $3,443 | $0 |
Sources: Gov. Code §66311.5; Ed. Code §17620 and State Allocation Board 2026 school fee maximum; Santa Ana Unified School District developer fees. Launch pricing runs through December 31, 2026. Comparison is general — every project differs.
Renting in Santa Ana
Renting out an ADU in Santa Ana
average asking rent for all homes in Santa Ana — up 40% since 2021. HUD's 2027 fair rent for a 2-bedroom in the area is $3,057.
Zillow Observed Rent Index, City of Santa Ana, Aug 2026 · HUD FY2027 FMR ADU for rental incomeSanta Ana ADUs can be rented for 30 days or more; short-term vacation rentals aren't allowed.
No owner-occupancy requirement for an ADU; it applies only to a JADU.
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: Santa Ana ADU/JADU Development Standards; Civil Code §1947.12. Comparison: HUD FY2027 2-bedroom Fair Market Rent, Santa Ana-Anaheim-Irvine area ($3,057) × 12 ÷ $271,900; U.S. Treasury (Oct 6, 2026); FTSE Nareit (Sep 2026); Zillow ZORI ÷ ZHVI, LA metro (Aug 2026); FDIC (Sep 2026). Not legal or investment advice.
Permits in Santa Ana
How your Santa Ana permit works — we handle it
Free lot check
Zoning, setbacks, transit distance, sewer and power for your Santa Ana address.
Plans & submittal
Our HCD-approved plans plus your site plan, submitted to Planning and Building.
City review
Ministerial review under Sec. 41-194; we answer comments.
Decision in 60 days
State law requires a decision on a complete ADU application within 60 days. Your ADU is built in our factory meanwhile.
Install & move in
Delivered from our Lathrop factory, installed in about a week, inspected, then your Certificate of Occupancy.
Based on the City’s ADU/JADU Development Standards and Gov. Code §66317. Santa Ana also offers City pre-approved ADU plans.
Why now
Start your Santa Ana 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.
Santa Ana ADU questions
Read our ADU guides, see all of California, or call (209) 214-6845.
Can I build an ADU on my lot in Santa Ana?
Most Santa Ana residential lots with a house can add a detached ADU of up to 1,000 sq ft and 20 ft (two stories), with 4-foot side and rear setbacks, plus a JADU. We check your address for free.
How much does an ADU cost in Santa Ana?
Our all-in prices are the same as anywhere in California: from $124,900 for a Small Studio to $271,900 for a 2 Bedroom ADU, with launch pricing through December 31, 2026. No impact fees under 750 sq ft, and school fees only above 500 sq ft.
How long does an ADU permit take in Santa Ana?
ADUs are approved ministerially, and state law requires a decision within 60 days of a complete application. Your ADU is built in our factory at the same time, so most projects take 4–6 months from signing to keys.
Do I need parking for an ADU in Santa Ana?
One space for a new unit — none if you are within half a mile of public transit, the ADU is a studio, a car share is on your block, or you're in a historic district.
Can I rent my Santa Ana ADU on Airbnb?
No. Santa Ana ADUs can't be short-term vacation rentals; rentals must be 30 days or more.
Do I have to live on the property?
No. There's no owner-occupancy requirement for an ADU in Santa Ana; it applies only to a JADU.
Can Bay Modular deliver to Santa Ana?
Yes. We build in our Lathrop factory and deliver statewide at the same all-in price, including Orange County.
Is an ADU a better investment than a rental property in Santa Ana?
For most homeowners with room on their lot, yes: you don't buy land. A 2 Bedroom ADU at HUD's 2027 fair rent for a 2-bedroom in the Santa Ana-Anaheim-Irvine area ($3,057) earns about 13.6% a year on its price before costs, vs. about 3.7% for a typical LA-metro rental home (Zillow, Aug 2026). Not investment advice.
Free · no obligation
Can you build an ADU on your Santa Ana lot?
Send your Santa Ana address. We'll check zoning, setbacks, transit distance and utilities, and send a fixed all-in price — permits included.
HCD-approved plans (#1585366) · 2-year warranty · factory in Lathrop, CA
Sources: California HCD Annual Progress Report data, Table A2 (City of Santa Ana, 2021–2025, updated Oct 2026); Zillow Observed Rent Index, City of Santa Ana (Aug 2026); HUD FY2027 Fair Market Rents (Santa Ana-Anaheim-Irvine); Santa Ana Zoning Code Sec. 41-194; City of Santa Ana ADU/JADU Development Standards and Pre-Approved ADU Plans. Prices: Bay Modular, October 2026. Not legal advice.