| intCompanyID | Company Name | Phone | Fax | Certification Status |
| 6884 | All 'n All Septic | (360) 509-7021 | | Active |
| 675 | A AAeration Services* | (360) 792-0478 | | Active |
| 581 | A+ Onsite* | (360) 830-4765 | (360) 830-4766 | Active |
| 6795 | AAA Septic LLC* | (360) 427-6110 | | Active |
| 693 | A-Advanced Septic Service Inc. | (253) 435-9999 | | Active |
| 9 | ABBA Excavating LLC | (253) 405-2576 | (253) 858-3661 | Active |
| 454 | A-Bell Excavating* | (253) 896-0043 | | Active |
| 6136 | Advanced Sewer Solutions Inc.* | (253) 259-6957 | | Active |
| 448 | All County Operations* | (360) 779-9609 | (360) 633-1693 | Active |
| 6484 | All In Septic & Excavation LLC* | (360) 598-4800 | | Active |
| 428 | Allied Design Inc. | (360) 620-7054 | | Active |
| 6840 | A-MAC Septic & Excavation* | (541) 254-0784 | | Active |
| 25 | Aqua Test Inc.* | (425) 432-9360 | (425) 413-9431 | Active |
| 540 | Aspen LLC | (360) 638-1230 | | Active |
| 32 | B&B Landscape & Design | (360) 692-2871 | (360) 698-5551 | Active |
| 6714 | Badger Excavation LLC* | (360) 602-9903 | | Active |
| 761 | BCS Development LLC | (360) 434-0111 | | Active |
| 48 | Brent Nuckols Construction, Inc. | (360) 697-3478 | (360) 697-6755 | Active |
| 691 | Cedar Septic Services | (360) 271-2895 | | Active |
| 69 | D&D Hauling | (360) 271-0403 | | Active |
| 692 | Dano's Septic* | (360) 373-4404 | | Active |
| 6288 | Doug Hemley Septic Installation* | (360) 204-3006 | | Active |
| 606 | E&R Landscaping & Excavation | (360) 509-1793 | | Active |
| 90 | Farm & Home Enterprises | (360) 674-2368 | | Active |
| 91 | Fast Track Construction Inc. | (360) 731-8066 | (360) 297-6932 | Active |
| 6210 | FloHawks LES* | (253) 393-2567 | | Active |
| 599 | G B Underground | (360) 731-3164 | | Active |
| 564 | Gettin' It Done Excavation LLC | (360) 358-5120 | | Active |
| 6678 | Greentree Dozing | (206) 463-3889 | | Active |
| 538 | Grizzly Septic Services* | (253) 857-3486 | | Active |
| 105 | Hemley's Septic Tank Cleaning Inc.* | (253) 851-3432 | (253) 851-2749 | Active |
| 5927 | Horizon Wastewater, Inc.* | (360) 550-4277 | | Active |
| 6763 | Indigo Septic Design Co. | (360) 779-5233 | | Active |
| 525 | Jim Campbell and Sons* | (253) 845-5827 | | Active |
| 528 | Kat Trax * | (253) 255-6799 | (253) 858-4779 | Active |
| 556 | Kitsap Septic Design & Monitoring Inc.* | (360) 473-3864 | (360) 479.3348 | Active |
| 644 | Lujack Construction LLC | (360) 710-5986 | | Active |
| 6896 | Maplewood Construction | (253) 377-0981 | | Active |
| 603 | Nathan Cleaver Septic Design | (360) 598-6546 | (360) 598-6548 | Active |
| 140 | Neil Triebenbach Services | (360) 670-8119 | | Active |
| 738 | Oien Construction Inc. | (360) 340-1981 | | Active |
| 159 | Pacific Specialty Contracting Inc. | (253) 851-5443 | | Active |
| 160 | Pacific Tractor & Excavating LLC | (253) 279-5344 | | Active |
| 6266 | Pat Hall Construction, Inc.* | (360) 443-2523 | | Active |
| 103 | Ron Hemley Septic Installations* | (360) 876-6104 | (253) 857-3241 | Active |
| 533 | Shumaker Construction | (360) 509-1222 | | Active |
| 6798 | Skinner Excavation Inc. | (360) 710-6489 | | Active |
| 6503 | Solid Ground Sitework LLC | (360) 865-4450 | | Active |
| 755 | South Fork Enterprises | (360) 271-7112 | | Active |
| 662 | South Shore Construction | (360) 275-0818 | | Active |
| 674 | Steve Kelly Construction Co. | (360) 297-3544 | | Active |
| 6797 | TC Septic Inc. | (360) 689-9958 | | Active |
| 6891 | TD Excavation* | (360) 271-0784 | | Active |
| 563 | Timberline Excavating | (360) 340-1582 | | Active |
| 756 | Trinity Excavating LLC | (360) 509-9805 | | Active |
| 6713 | VET Industrial | (360) 340-3845 | | Active |
| 530 | Whitworth Excavating Inc | (360) 638-2300 | | Active |