Short answer: If you want the lowest entry price and rent from day one, Santa Ana wins. If you want to buy a house and build, with the deepest pool of ADU comps in Orange County, Garden Grove wins. If you want the strongest rents and bigger lots on the Huntington Beach border, Westminster wins, but you pay the most to get in. On my numbers, all three run slightly negative at 25% down after you build a 2-bedroom ADU, and all three cash flow about $1,370 to $1,520 a month at 50% down.
These three cities touch each other in central Orange County, and together they finaled 610 ADUs in 2025. That’s more ADU activity than almost any other cluster in the county. Below is how they compare on price, ADU rules, rents, market speed and the monthly payment math, using my fall 2026 MLS reports and each city’s current ADU code.
Last updated: October 2026. Dylan Serna, The ADU Realtor.
Garden Grove vs. Westminster vs. Santa Ana at a Glance
| Garden Grove | Westminster | Santa Ana | |
|---|---|---|---|
| Median sale price, all homes (Redfin) | About $1,010,000 (Sept. 2026) | About $1,186,000 (Sept. 2026) | About $826,000 (3 months to Aug. 2026) |
| ADU homes for sale (my fall 2026 reports) | 11 active, $899K to $2.4M; Sept. sales $1.02M to $1.2M | Thin inventory; fair prices go fast, high prices get cut | 13 active, median $1,050,000; 8 under $1.2M |
| Max detached ADU size | 850 sq ft (studio/1 bed), 1,200 sq ft (2+ bed) | 1,200 sq ft | 1,000 sq ft (800 if you also add a JADU) |
| Detached ADU height | 16 ft (18 ft near major transit) | 16 ft state baseline | 20 ft, 2 stories |
| Separation from the house | 6 ft (HCD says it can’t apply to an 800 sq ft unit) | 6 ft | 15 ft (can be reduced for 800 sq ft or less) |
| 2-bed ADU rent | About $2,900 (range $2,350 to $3,800) | About $2,800 (3-bed about $3,400) | About $2,600 (range $2,200 to $3,100) |
| ADUs finaled in 2025 / since 2005 | 244 / 1,722 | 194 / 752 | 172 / 723 |
| Rule that trips up buyers | HCD findings on the local ordinance | One ADU per lot in the local code; sewer and water capacity | Local rent stabilization; 15-ft separation |
Sources: Garden Grove Municipal Code Chapter 9.54, Westminster Municipal Code 17.400.135, Santa Ana ADU and JADU development standards, Cal State Fullerton’s 2005 to 2025 ADU report, Redfin city data and CRMLS. Rules change, so confirm any parcel with the city before you write an offer.
What It Costs to Get In
These three cities are close on a map but about $360,000 apart on median price.
- Santa Ana is the cheapest, with a median near $826,000. That number includes a lot of condos, but it’s still the only one of the three where I regularly see ADU homes under $900,000. In my September Santa Ana report, 8 of 13 ADU listings were under $1.2 million, and one closed in August at $955,000, 4.4% under list with $19,100 in seller credits.
- Garden Grove runs about $1,010,000, up 1% year over year. The interesting number is the gap: ADU homes asked a median of $1.55 million in October, but the ones that sold in September closed at a median of $1,120,000. Buyers are paying for the fairly priced homes and skipping the rest.
- Westminster is the priciest at about $1,186,000, up 9.3% year over year. Part of that is the mix. The 92683 neighborhoods near Huntington Beach have more 7,000 sq ft lots and newer, larger homes, and those pull the median up.
For the payment math below, I use realistic prices for a 3-bedroom house on a lot that fits a 2-bedroom ADU: $950,000 in Santa Ana, $1,050,000 in Garden Grove and $1,100,000 in Westminster.
ADU Rules Compared
All three cities follow state ADU law, so the basics match: 4-foot side and rear setbacks, approval within 60 days with no public hearing, no owner-occupancy for an ADU by itself, no impact fees under 750 sq ft and no short-term rentals. The state rules are on California HCD’s ADU page. The differences are size, height, separation and a few local catches.
Garden Grove: big lots and the most ADU experience
Garden Grove allows a detached ADU up to 1,200 sq ft for 2+ bedrooms, at 16 feet (18 near major transit). It has finaled more ADUs than any city in Orange County, 1,722 since 2005. That matters for you in two ways: appraisers have real comps, and local builders know plan check.
The catch is paperwork. In March 2026, HCD told the city that parts of its ordinance don’t comply with state law, including minimum unit sizes, some setback rules and the 6-foot separation on state-protected units. That mostly works in a buyer’s favor, but your designer needs to know which version plan check is using. I cover every line in my Garden Grove ADU ordinance guide.
Westminster: generous size cap, stricter unit count
Westminster allows a detached ADU up to 1,200 sq ft with a 6-foot separation from the house. On a 7,000 sq ft lot, that fits a real 3-bedroom, 2-bath unit. Two local rules to check:
- Unit count. The city code allows one ADU and one JADU only when both are inside existing space. Otherwise it’s one unit. State law allows more combinations, and starting in 2027 it allows two detached ADUs, so plan on state law controlling and get Planning’s answer in writing.
- Sewer and water. The City Engineer can restrict ADUs where service is too limited. Ask before you remove contingencies.
The best Westminster ADU lots I see are RV-access corners in 92683. I ran full numbers on one in Westminster RV corner lots on the Huntington Beach border.
Santa Ana: smaller cap, taller units and a separation rule
Santa Ana caps detached ADUs at 1,000 sq ft, dropping to 800 sq ft if you also add a JADU. In exchange, it allows 20 feet and two stories, which is useful on the city’s many smaller lots. Two things to know:
- The 15-foot separation. A detached ADU over 800 sq ft has to sit 15 feet from the house. On a shallow lot, that can push you to a smaller unit or a second story. Garage conversions are exempt.
- Rent stabilization. Santa Ana is the only Orange County city with broad rent control. Under its Rent Stabilization and Just Cause Eviction Ordinance, covered units can go up 2.87% from September 2026 through August 2027. It applies to buildings built on or before February 1, 1995, so a new ADU is outside the cap. Confirm the house’s status before you buy. I show the long-term effect in what Santa Ana’s 2.87% rent cap means for your ROI.
What changes in 2027 for all three
Starting January 1, 2027, AB 956 allows two detached new-construction ADUs on many single-family lots, and SB 1117 limits impact fees to the square footage above 750. That helps Westminster’s bigger lots the most, since its local code is the most restrictive on unit count today. My breakdown is in what AB 956 and SB 1117 mean for ADU owners.
What ADUs Rent For in Each City
| ADU type | Garden Grove | Westminster | Santa Ana |
|---|---|---|---|
| 1 bed | $2,000 to $2,400 | About $2,100 | $1,900 to $2,300 |
| 2 bed | $2,600 to $3,200 | About $2,800 | $2,400 to $2,800 |
| Newer 1,100 to 1,200 sq ft, 3 bed | $3,200 to $3,800 | $3,400 to $4,300 | Not allowed above 1,000 sq ft detached |
| Main house, 3 bed | About $3,900 | $4,200 to $4,400 | About $3,600 |
These come from rented ADUs on current listings and recent leases. In Santa Ana, 1329 W McFadden had a new 2-bed ADU renting for $2,600 and the front house for $3,575. Detail by size is in my Westminster ADU rent guide and what Santa Ana ADU rents look like in 2026. Garden Grove 1 and 2-bed ranges are my estimates from recent leases.
The pattern: Westminster rents the highest, but it also costs the most. Santa Ana rents the lowest, but its entry price is low enough that the rent covers a bigger share of the payment.
How Fast ADU Homes Are Selling
- Garden Grove: 11 active, 3 in escrow and 4 sold in September. The two lowest-priced homes sold in 5 days over asking, while homes over $1.5 million sat 30 to 189 days. See the October Garden Grove ADU report.
- Westminster: The clearest buyer’s market of the three. A fairly priced three-unit lot went into escrow in about two weeks, while overpriced homes cut $50,000 to $688,000. See the Westminster fall ADU report.
- Santa Ana: The most choices under $1.2 million, and sellers are giving credits. Citywide, homes took a median 44 days to sell in August.
For a buyer, that means the most negotiating room is in Westminster and Santa Ana. In Garden Grove, a fairly priced home under $1.2 million won’t last a week.
The Payment Math: Buy a House, Build a 2-Bedroom ADU
I keep this simple: total monthly payment (principal, interest, taxes and insurance) against total rent. Same plan in each city. Buy a 3-bedroom house, pay cash for a 1,000 sq ft, 2-bedroom detached ADU at about $330,000 all-in, then rent both. A 1,000 sq ft unit fits under all three cities’ caps.
Assumptions: 7.75% investment-property rate on a 30-year loan, property tax at 1.15% of purchase price plus build cost, and $200 a month for insurance.
| Garden Grove | Westminster | Santa Ana | |
|---|---|---|---|
| Purchase price | $1,050,000 | $1,100,000 | $950,000 |
| Main house rent + ADU rent | $3,900 + $2,900 = $6,800 | $4,200 + $2,800 = $7,000 | $3,600 + $2,600 = $6,200 |
| 25% down: cash in (down + build) | $592,500 | $605,000 | $567,500 |
| Monthly PITI | About $7,160 | About $7,480 | About $6,530 |
| Rent minus PITI | About -$360 | About -$480 | About -$330 |
| 50% down: cash in (down + build) | $855,000 | $880,000 | $805,000 |
| Monthly PITI | About $5,280 | About $5,510 | About $4,830 |
| Rent minus PITI | About +$1,520 | About +$1,490 | About +$1,370 |
How I read this table:
- At 25% down, all three run $330 to $480 a month negative. That makes them holds for appreciation and principal paydown, not cash-flow plays. Santa Ana is the closest to even, and it needs the least cash.
- At 50% down, all three cash flow. Garden Grove and Westminster lead by about $120 to $150 a month, but they also need $50,000 to $75,000 more cash than Santa Ana.
- Westminster has the most upside per lot. Build a 3-bedroom, 1,100 sq ft ADU for about $360,000 instead and its ADU rent rises to about $3,400, which adds about $570 a month after the added property tax. Santa Ana can’t do that with a detached unit, because its cap is 1,000 sq ft.
- Santa Ana’s numbers are the most likely to stay flat. If the main house falls under rent stabilization, its rent grows about 3% a year at most. Garden Grove and Westminster follow the state cap under AB 1482, which is higher.
These are planning numbers, not quotes. Your rate, insurance and build bid will change them, so I re-run this on every property a client is serious about.
Which City Fits Your Plan?
Choose Garden Grove if…
- You want to buy a house and build, and you want the safest appraisal and resale story.
- You want a 1,200 sq ft ADU on a big lot near $1 million.
- You can move fast when a fairly priced home hits the market.
Choose Westminster if…
- You want the highest rents and a 3-bedroom ADU.
- You like a Huntington Beach-adjacent location with Huntington Beach Union High School District schools in parts of 92683.
- You’re patient and want to negotiate with sellers who are cutting price.
Choose Santa Ana if…
- You want the lowest cash in and rent from day one by buying with the ADU already built.
- You’re comfortable underwriting slower rent growth on the main house.
- You’re fine with a 1,000 sq ft cap, or you want a two-story ADU on a smaller lot.
Whichever city you pick, run the lot through my escrow ADU verification checklist before your contingencies come off.
Frequently Asked Questions
Which is cheapest for an ADU investment: Garden Grove, Westminster or Santa Ana?
Santa Ana. Its median sale price is about $826,000, compared with about $1,010,000 in Garden Grove and $1,186,000 in Westminster (Redfin, late summer 2026).
Which city allows the biggest ADU?
Garden Grove and Westminster both allow detached ADUs up to 1,200 sq ft. Santa Ana caps them at 1,000 sq ft, or 800 sq ft if you also add a JADU.
Does Santa Ana rent control apply to a new ADU?
No. Santa Ana’s rent cap applies to buildings built on or before February 1, 1995, so a newly built ADU is outside it. Check the main house’s status with the city.
Where do ADUs rent for the most?
Westminster. Larger second units there rent for about $3,300 to $4,300. Garden Grove ADUs rent for about $2,350 to $3,800, and Santa Ana for about $2,200 to $3,100.
Do I have to live on the property to build an ADU?
No. None of the three cities requires owner-occupancy for an ADU by itself. Owner-occupancy applies if you add a JADU.
How much down payment do I need for a buy-and-build ADU deal here?
Investment loans need at least 25% down. In these three cities, that leaves you about $330 to $480 a month short after building a 2-bedroom ADU. Around 50% down is where the property cash flows.
Compare Real Properties, Not Averages
Tell me your budget and goal, and I’ll pull ADU-potential homes in Garden Grove, Westminster and Santa Ana with projected house rent, ADU rent and build cost for each one. Then we tour the best of them together.
👉 Book a buyer ADU consult call to go through your options with Dylan
Prefer to talk now? Call Dylan Serna, ADU Realtor at 714-860-2868.
Dylan Serna | The ADU Realtor | eXp Realty | DRE #02217359
This post is general information, not legal, tax or financial advice. Prices, rents and payments are estimates based on fall 2026 MLS data and public sources. Confirm ADU rules for any specific property with the city.
