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ADU Builders in Rancho Santa Margarita, CA

41 builders · ranked by Google rating and review volume · 18 CSLB license verified

★ Featured ADU builder

Featured ADU builder — this spot is open

Put your ADU company at the top of this page, in front of Rancho Santa Margarita homeowners who are comparing builders right now. Includes your logo, project photos, a direct call button and a link to your website.

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Rancho Santa Margarita is home to about 47,949 people (2020 Census) in Orange County. We found 41 ADU builders and contractors that show up for Rancho Santa Margarita homeowners on Google Maps, 1 of them based in the city itself. Their average Google rating is 4.8 stars. 11 market themselves specifically as ADU builders, and 1 mention garage conversions. 18 have a matched, active CSLB license shown with a verified badge. The top-rated by our review-weighted score are Tixan Construction, Integria Design Build and Renovex Construction.

In Orange County, HOA and design-standard questions come up often. State law voids CC&Rs that ban ADUs, but HOAs can still apply reasonable objective standards. Compact lots make attached units and garage conversions popular.

#1

Tixan Construction

5.0 (41 Google reviews)
✔ CSLB License Verified #1105549

21502 Firwood, Lake Forest, CA 92630

Serves Rancho Santa Margarita · based in Lake Forest
Remodels & additionsGeneral contractor
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#2

Integria Design Build

5.0 (36 Google reviews)
✔ CSLB License Verified #1107580

20381 Lake Forest Dr suite b-4, Lake Forest, CA 92630

Serves Rancho Santa Margarita · based in Lake Forest
Design-buildGeneral contractor
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#4

Bud Remodeling

5.0 (26 Google reviews)
✔ CSLB License Verified #1067878

22772 Centre Dr #100, Lake Forest, CA 92630

Serves Rancho Santa Margarita · based in Lake Forest
Remodels & additionsGeneral contractor
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#5

RIA Group

5.0 (25 Google reviews)

Service-area business · Rancho Santa Margarita

Serves Rancho Santa Margarita · based in Rancho Santa Margarita
Remodels & additionsHome builderGeneral contractor
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#7

Kol & Co.

5.0 (24 Google reviews)

23431 Blue Bird Dr, Lake Forest, CA 92630

Serves Rancho Santa Margarita · based in Lake Forest
Remodels & additionsHome builderGeneral contractor
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#10

D & K Builders

5.0 (17 Google reviews)

Service-area business · Lake Elsinore

Serves Rancho Santa Margarita · based in Lake Elsinore
Remodels & additionsHome builderGeneral contractor
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#11

OC Quality Builders

4.9 (30 Google reviews)
✔ CSLB License Verified #1148925

22981 Triton Way Unit C, Laguna Hills, CA 92653

Serves Rancho Santa Margarita · based in Laguna Hills
Remodels & additionsHome builderGeneral contractor
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#12

IGS Construction

5.0 (14 Google reviews)
✔ CSLB License Verified #1087602

23362 Madero # L, Mission Viejo, CA 92691

Serves Rancho Santa Margarita · based in Mission Viejo
Remodels & additionsHome builderGeneral contractor
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#14

ProHome Remodels

4.9 (18 Google reviews)
✔ CSLB License Verified #1140564

25381 Commercentre Dr, Lake Forest, CA 92630

Serves Rancho Santa Margarita · based in Lake Forest
Remodels & additionsHome builderGeneral contractor
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#18

Kash Construction Inc

5.0 (7 Google reviews)
✔ CSLB License Verified #1028459

23301 Ridge Rte Dr, Laguna Hills, CA 92653

Serves Rancho Santa Margarita · based in Laguna Hills
Remodels & additionsGeneral contractor
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#19

Excel Design & Build

5.0 (6 Google reviews)
✔ CSLB License Verified #956734

25108 Marguerite Pkwy STE. A #4, Mission Viejo, CA 92692

Serves Rancho Santa Margarita · based in Mission Viejo
Design-buildGeneral contractor
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#20

SDB

5.0 (6 Google reviews)
✔ CSLB License Verified #1072529

27601 Forbes Rd #16, Laguna Niguel, CA 92677

Serves Rancho Santa Margarita · based in Laguna Niguel
Home builderGeneral contractor
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#21

Tech LA Builder

5.0 (4 Google reviews)
✔ CSLB License Verified #1097275

20381 Lake Forest Dr, Lake Forest, CA 92630

Serves Rancho Santa Margarita · based in Lake Forest
General contractor
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#22

Capstone Construction Service

5.0 (4 Google reviews)
✔ CSLB License Verified #1146286

Service-area business · Rancho Santa Margarita

Serves Rancho Santa Margarita · based in Rancho Santa Margarita
Home builderGeneral contractor
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#26

Plus Home ADU

5.0 (3 Google reviews)
✔ CSLB License Verified #1062063

Service-area business · Aliso Viejo

Serves Rancho Santa Margarita · based in Aliso Viejo
ADU specialistRemodels & additionsHome builderGeneral contractor
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#28

CCS ADU Services

5.0 (2 Google reviews)

Service-area business · San Clemente

Serves Rancho Santa Margarita · based in San Clemente
ADU specialistHome builder
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#33

DWELLO ADU INC

5.0 (1 Google reviews)

23361 Madero Ste 235, Mission Viejo, CA 92691

Serves Rancho Santa Margarita · based in Mission Viejo
ADU specialistGeneral contractor
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#34

OC Coastal Builder

5.0 (1 Google reviews)
✔ CSLB License Verified #992307

Service-area business · Mission Viejo

Serves Rancho Santa Margarita · based in Mission Viejo
Remodels & additionsGeneral contractor
CallView profile
#35

EA Design And Build

4.2 (5 Google reviews)
✔ CSLB License Verified #1080602

Service-area business · Rancho Santa Margarita

Serves Rancho Santa Margarita · based in Rancho Santa Margarita
Design-build
CallWebsiteView profile
#38

Paragon Design & Construction Inc.

2.0 (5 Google reviews)
✔ CSLB License Verified #914888

Service-area business · Rancho Santa Margarita

Serves Rancho Santa Margarita · based in Rancho Santa Margarita
Remodels & additionsGeneral contractor
CallView profile
#41

Seagull Construction OC

No rating yet (0 Google reviews)
✔ CSLB License Verified #1154091

28351 Via Alfonse, Laguna Niguel, CA 92677

Serves Rancho Santa Margarita · based in Laguna Niguel
Remodels & additionsHome builderGeneral contractor
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Permits and pre-approved plans in Rancho Santa Margarita

ADU permits in Rancho Santa Margarita go through the city's building or planning department. Under AB 1332, every California city and county had to set up a pre-approved ADU plan program by January 1, 2025, so ask Rancho Santa Margarita whether it has approved plans you can use. See our pre-approved plans guide and California ADU law summary.

Planning an ADU in Rancho Santa Margarita? Start here

How to Choose an ADU Builder in Southern California: 15-Point ChecklistSB 9 vs ADU: Lot Splits, Duplexes and Backyard Units in CaliforniaHow Much Does It Cost to Build an ADU in Southern California?Garage Conversion ADU Cost in Southern California (and What Drives It)

All ADU guides →

Rancho Santa Margarita ADU FAQ

How many ADU builders serve Rancho Santa Margarita?

Our directory lists 41 ADU builders and contractors that appear for Rancho Santa Margarita on Google Maps, including companies based in nearby Orange County communities.

Do I need a permit to build an ADU in Rancho Santa Margarita?

Yes. ADUs need a building permit from the City of Rancho Santa Margarita, which must approve or deny a complete application within 60 days under state law. Many cities also offer pre-approved plans that speed up review.

How much does an ADU cost in Rancho Santa Margarita?

Most Southern California detached ADUs land around $350 to $550 per square foot all-in, garage conversions around $200 to $350, and JADUs around $50,000 to $150,000. Use our ADU cost estimator and get three itemized bids.

How are Rancho Santa Margarita ADU builders ranked here?

By Google rating weighted by the number of reviews, so a 4.9 with 200 reviews ranks above a 5.0 with 3. Featured placements are clearly labeled and don't affect the organic ranking.

Nearby cities in Orange County

Anaheim 114Santa Ana 97Irvine 107Huntington Beach 88Garden Grove 97Fullerton 23Orange 95Costa Mesa 103Mission Viejo 59Westminster 53Lake Forest 60Newport Beach 96
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