ADU Contractors in Monrovia, CA — License-Verified Contractors
Every contractor below holds an active California license with an office of record in Monrovia, verified against CSLB public data as of November 6, 2026: general builders — A (General Engineering) and B (General Building), the classifications that can build an ADU — and the licensed trades ADU construction uses, C-10 Electrical, C-36 Plumbing and C-5 Framing & Rough Carpentry. Listings are alphabetical; the featured builder is labeled, never ranked.
ADU rules — setbacks, size limits, parking, and fees — are set by the local jurisdiction and change often. Before you hire, read the ADU permit process guide and the Southern California ADU cost guide, and verify any license free at CSLB.
Mars Construction Industries Corp
ADU Cities' own design-build team
CSLB #1138550 · A · B · C-36 · C-20
Building ADUs across Los Angeles, Orange, Riverside, San Bernardino, San Diego & Ventura counties
203 license-verified contractors based in Monrovia — page 1 of 5
A - Custom Door & Window
BAae Services Incorporated
C-10Air Tro Incorporated
BC-10C-20C-36C-38Akk Construction
BAlbrecht Paul
BAll Systems Pros Inc
C-36Allen John W
C-36Alpha Construction And Restoration
BAlvic Home Improvement Inc
BAm United Enterprises LLC
BAmerican Pipeline Services
AC-20C-36C-55HAZAmerican Skylight LLC
BAndys Carpentry
C-5Aram Barsamian Constuction
BArchbox Studio Design & Build
Archbox Studio
BArrowbear Electric
C-10Asset Air & Plumbing
Asset Pumping Services Inc
C-10C-20C-36B And H Signs
3D Partners Group Inc
BD-42B J B Construction
BB L G Construction
BB L Hall Inc
AHAZBakewell Construction
BBarsam Construction
BBednar Scott A Construction
BBlankenbiller Richard
ABowden Development Inc
BBrian Dario
BBrkich Robert Construction Corp
ABrown - United Inc
BBruce Paez Construction
BBrunos Electric
C-10Bubalo Steve Construction Co
AC-31Caldera Power Services Inc
C-10Carl Maertens
BC-36Carlson Construction And Remodeling
BCasa Construction
Glacier Trading Corporation
BCasanova Renovations & Roofing
Citiwide Builders Inc
BC-39Cass James Edward III
BCass Jim Construction & Welding
BC-60Castellano Gilbert
C-10Century Sewer Services
C-36C-42Charles Hayes Construction Inc
BChelsea Construction Corp
BChm Construction
BClaros Construction
BClopton John Construction
BCollins R J Plumbing Co Inc
C-36Concept Builders
Brix Co Inc
BCooke R Construction Inc
BC-29Data source: CSLB public records as of November 6, 2026 · Verify any license at CSLB