| A - 1 Larkin & Son | Kevin Joseph Larkin | — | (415) 827 9373 | Windows, patio, painters | Lucerne · Lake County | — | — |
| A And E Electric Company | Ricky Allen Alves | — | (510) 253 8193 | Electricians | Clearlake Oaks · Lake County | — | — |
| A B Builders | A B Builders | — | (707) 490 2304 | GC, remodel, ADU | Hidden Valley Lake · Lake County | — | — |
| A B C Sewer And Drain | Adam Christopher Maldonado | — | (707) 994 4411 | Other | Lakeport · Lake County | — | — |
| A R E Construction | Alvin Ricky Martinez | — | (707) 541 8121 | GC, remodel, ADU | Lakeport · Lake County | — | — |
| A V R Tree Service | Adelbert Anthony Vonrekowski | — | (707) 994 1849 | Tree | Clearlake · Lake County | — | — |
| A-1 Construction | Thad James Henninger | — | (707) 350 1818 | GC, remodel, ADU | Lakeport · Lake County | — | — |
| A-t Wanzer Grading And Excavating INC | Anthony James Wanzer | — | (707) 262 0799 | Other | Lakeport · Lake County | — | — |
| Aaa Pump Service | Matthew Allen Black | — | (707) 349 5113 | Other | Lakeport · Lake County | — | — |
| Aaron Christensen DBA Arrowhead Heating & Cooling | Arrowhead Heating & Cooling | — | (707) 295 2276 | HVAC | Middletown · Lake County | — | — |
| Abbotts Heating & Air Conditioning | Abbotts Heating & Air Conditioning | — | (707) 263 5722 | HVAC | Lakeport · Lake County | — | — |
| Above Expectation | Above Expectation | — | (707) 779 2350 | GC, remodel, ADU | Kelseyville · Lake County | — | — |
| Absolute Action Construction | Derek George Soeth | — | (415) 497 1272 | GC, remodel, ADU | Lower Lake · Lake County | — | — |
| Acl Tree Works LLC | Acl Tree Works LLC | — | (626) 757-3041 | Tree | Crestline · Lake County | — | — |
| Action Sanitary INC | Jerry Lee Campo | — | (707) 994 5068 | Other | Lower Lake · Lake County | — | — |
| Aden Iv Construction | William Martin Aden | — | (707) 815 0215 | GC, remodel, ADU | Middletown · Lake County | — | — |
| Advanced Electronic Security Systems | Advanced Electronic Security Systems | — | (707) 994 9315 | Electricians | Clearlake · Lake County | — | — |
| Al's Home Enhancement | Al's Home Enhancement | — | (909) 279 2201 | GC, remodel, ADU | Kelseyville · Lake County | — | — |
| Alderbuilt Construction | Forest Eagelton Aldrich | — | (831) 238 2505 | GC, remodel, ADU | Kelseyville · Lake County | — | — |
| Alex Ciddio Woodcraft INC | Alexander Julian Ciddio | — | (707) 235 3924 | GC, remodel, ADU | Middletown · Lake County | — | — |
| All In One Construction | Scott Douglas Jerden | — | (707) 628 7326 | GC, remodel, ADU | Kelseyville · Lake County | — | — |
| All Seasons Construction | Keith Dennis Beeson | — | (707) 355 1718 | GC, remodel, ADU | Cobb · Lake County | — | — |
| Alliance Roofing | Alliance Roofing | — | (530) 241-6945 | Other roofers | Shasta Lake · Lake County | — | — |
| Amazing Kind Miracles | Amazing Kind Miracles | — | (707) 994 4423 | Other | Lower Lake · Lake County | — | — |
| American Eagle Tree Service | American Eagle Tree Service | — | (818) 457-0891 | Tree | Lake View Terrace · Lake County | — | — |
| Andrew Jonathon Jones | Andrew Jonathon Jones | — | (850) 485 5191 | Other | Lakeport · Lake County | — | — |
| Anthony Samuel Martinez DBA Asm Construction | Anthony Samuel Martinez | — | (707) 599 1603 | GC, remodel, ADU | Clearlake Oaks · Lake County | — | — |
| Applewood Property Management | Applewood Property Management | — | (707) 937-1915 | Property managers | Mendocino · Lake County | — | — |
| Aqua Products Pool & Spa Supplies | Mark Dennis Browning | — | (707) 263 6052 | Pool | Lakeport · Lake County | — | — |
| Aquarius Water Systems | David Glenn Clark | — | (707) 262 2963 | Other | Cobb · Lake County | — | — |
| Arbeez Plumbing | Arbeez Plumbing | — | (707) 349 1200 | Other | Clearlake Oaks · Lake County | — | — |
| Arrowhead Property Rental | Arrowhead Property Rental | — | (909) 337-2403 | Property managers | Lake Arrowhead · Lake County | — | — |
| Asl Electric INC | Asl Electric INC | — | (949) 589-9275 | Electricians | Lake Forest · Lake County | — | — |
| Audac | Brian Keith Laws | — | (415) 459 3095 | Other | Clearlake Oaks · Lake County | — | — |
| Avalos Sheet Metal | Avalos Sheet Metal | — | (707) 360 7219 | Other roofers | Lower Lake · Lake County | — | — |
| Bach Electric | Craig Alan Bach | — | (707) 274 3346 | Electricians | Lucerne · Lake County | — | — |
| Balentine Wood Flooring Co | Robert Michael Balentine | — | (707) 322 1632 | Other | Lakeport · Lake County | — | — |
| Barnell Heating And A C | Barnell Heating And A C | — | (707) 328 8498 | HVAC | Kelseyville · Lake County | — | — |
| Barnett Marine Engineering LLC | Scott Jason Barnett | — | (707) 245 4823 | Other | Upper Lake · Lake County | — | — |
| Barrios Construction | Timothy Ramon Barrios | — | (530) 718 9401 | GC, remodel, ADU | Lower Lake · Lake County | — | — |