| Company | Location | Certifications | License # |
|---|---|---|---|
| 24/7 Plumbology | Huntsville, MO | Installer (Level Basic) | 38976 |
| A & C Excavating | New London, MO | Installer (Level Advanced) | 36752 |
| Accurate Bobcat Service | Auxvasse, MO | Installer (Level Basic) | 33443 |
| All American Septic | Wentzville, MO | Installer (Level Basic) | 38694 |
| All Clear Pumping And Sewer Llc | Centertown, MO | Installer (Level Advanced) | 36716 |
| All Clear Pumping And Sewer Llc | Centertown, MO | Installer (Level Advanced) | 36021 |
| Arthur Ratliff Tree And Stump Removal | Columbia, MO | Installer (Level Basic) | 39327 |
| Barry Maupin Excavating, Inc | Fulton, MO | Installer (Level Basic) | 37200 |
| Bentlage Bobcat | Ashland, MO | Installer (Level Advanced) | 38435 |
| Billy Orf & Sons | Bowling Green, MO | Installer (Level Advanced) | 32366 |
| Bio Gard | Columbia, MO | Installer (Level Basic) | 39528 |
| Bio-Gard | Columbia, MO | Installer (Level Basic) | 38869 |
| Bio-Gard Inc | Columbia, MO | Installer (Level Advanced) | 30153 |
| Bio-Gard Inc. | Columbia, MO | Installer (Level Advanced) | 38083 |
| Bio-Gard Inc. | Columbia, MO | Installer (Level Advanced) | 38871 |
| Bio-Gard, Inc | Columbia, MO | Installer (Level Advanced) | 36448 |
| Bio-Gard, Inc | Columbia, MO | Installer (Level Advanced) | 36446 |
| Boyer Nichols | — | Installer (Level Basic) | 39431 |
| Brandl'S Construction Services Llc | Fulton, MO | Installer (Level Basic) | 39098 |
| Brandl'S Construction Services Llc | Fulton, MO | Installer (Level Basic) | 39099 |
| Brookside General Contracting | Auxvasse, MO | Installer (Level Basic) | 39323 |
| Butcher Construction & Excavation | Fulton, MO | Installer (Level Advanced) | 35280 |
| C.L. Richardson | Ashland, MO | Installer (Level Advanced) | 37387 |
| C.Taylor Contracting Llc | Hermann, MO | Installer (Level Basic) | 39394 |
| Caldwell Construction | Center, MO | Installer (Level Basic) | 36092 |
| Carter Concrete & Excavating | Harrisburg, MO | Installer (Level Basic) | 36689 |
| Castle Custom Homes | Columbia, MO | Installer (Level Advanced) | 37931 |
| Central Missouri Home Inspections Llc | Columbia, MO | Installer (Level Advanced) | 33779 |
| Christopher Lane | — | Installer (Level Basic) | 39495 |
| Connor Brooks Excavating Llc | Hallsville, MO | Installer (Level Advanced) | 38759 |
| Curt'S Construction | Fulton, MO | Installer (Level Advanced) | 33416 |
| Cutting Edge Excavating Llc | Centralia, MO | Installer (Level Basic) | 38762 |
| D & L Trenching | Huntsville, MO | Installer (Level Basic) | 30613 |
| Dale Brower Custom Digging | Bellflower, MO | Installer (Level Basic) | 31621 |
| Db Plumbing Llc | Paris, MO | Installer (Level Basic) | 39111 |
| Dc Septic & Drain | Troy, MO | Installer (Level Basic) | 39050 |
| Diversified Excavating Llc | Columbia, MO | Installer (Level Basic) | 37966 |
| Djv Construction | Monroe City, MO | Installer (Level Basic) | 34326 |
| Donaldson Excavating | Mexico, MO | Installer (Level Basic) | 32639 |
| Dotson & Gibbs Inc | New London, MO | Installer (Level Advanced) | 36094 |
| Elite Wastewater Solutions Llc | Sturgeon, MO | Installer (Level Advanced) | 37560 |
| Eric Alexander | — | Installer (Level Advanced) | 39517 |
| Exact Excavation Llc | Auxvasse, MO | Installer (Level Advanced) | 39073 |
| Fischer Excavating Llc | Truxton, MO | Installer (Level Advanced) | 35643 |
| Flowmaster Construction Llc | Mexico, MO | Installer (Level Advanced) | 35516 |
| Gallop Excavating Llc | Madison, MO | Installer (Level Basic) | 39423 |
| Garek Purcell | — | Installer (Level Basic) | 39547 |
| Good Neighbor Soil Evaluators | Hallsville, MO | Installer (Level Basic) | 38580 |
| H & H Construction | Madison, MO | Installer (Level Basic) | 32609 |
| Hardcore Excavating | Boonville, MO | Installer (Level Basic) | 39129 |
| Haskamp Excavation | Columbia, MO | Installer (Level Basic) | 39434 |
| Henry Excavating | Auxvasse, MO | Installer (Level Advanced) | 38212 |
| Ice Services Llc | Warner Robins, MO | Installer (Level Advanced) | 39350 |
| Integrity Earthworks Llc | Fulton, MO | Installer (Level Advanced) | 37935 |
| J.D. Kelly Excavating Inc | Columbia, MO | Installer (Level Basic) | 38386 |
| Joe Brooks | Centralia, MO | Installer (Level Basic) | 39181 |
| Kc Land & Lawn | Warrenton, MO | Installer (Level Advanced) | 39492 |
| Kennett Exc | Columbia, MO | Installer (Level Basic) | 32649 |
| Kleinsorge Construction Llc | Mexico, MO | Installer (Level Basic) | 39494 |
| M & M Landscaping And Construction, Llc | Eugene, MO | Installer (Level Advanced) | 32264 |
| M. Turpin Services | Foristell, MO | Installer (Level Basic) | 39333 |
| M. Turpin Services | Foristell, MO | Installer (Level Advanced) | 39352 |
| M. Turpin Services | Foristell, MO | Installer (Level Advanced) | 39366 |
| Marvin Perrigo Construction Llc | Tebbetts, MO | Installer (Level Advanced) | 35266 |
| Mid Missouri Underground Llc | Columbia, MO | Installer (Level Basic) | 39104 |
| Midstate Builders | New Franklin, MO | Installer (Level Advanced) | 31146 |
| National Property Inspections Como | Columbia, MO | Installer (Level Basic) | 39538 |
| Nelsons Land And Road Maintenance Llc | Fulton, MO | Installer (Level Basic) | 38509 |
| Nick Garrett Digging & Grading Llc | Jonesburg, MO | Installer (Level Advanced) | 38236 |
| Orf Construction Inc | Bowling Green, MO | Installer (Level Advanced) | 34805 |
| Orf Construction Inc | Bowling Green, MO | Installer (Level Advanced) | 30221 |
| Powers Construction Llc. | Hartsburg, MO | Installer (Level Basic) | 37982 |
| Pro Plumbing Inc | Huntsville, MO | Installer (Level Basic) | 35768 |
| Pro Pumping & Hydrojetting Llc | Columbia, MO | Installer (Level Advanced) | 38405 |
| Rebecca Purcell | — | Installer (Level Basic) | 39548 |
| Rick Mckinney Const | Paris, MO | Installer (Level Basic) | 33914 |
| Roger Morris | Ashland, MO | Installer (Level Basic) | 33434 |
| Russell Sapp Exc | Columbia, MO | Installer (Level Basic) | 32656 |
| S & A Equipment & Builders | Fulton, MO | Installer (Level Advanced) | 34968 |
| Seth Paul Excavating, Inc. | Columbia, MO | Installer (Level Advanced) | 33428 |
| Siegel Excavating | Montgomery City, MO | Installer (Level Basic) | 38306 |
| Smith Excavating Llc | Mokane, MO | Installer (Level Basic) | 38124 |
| Smith Septic | Montgomery City, MO | Installer (Level Basic) | 31194 |
| Sscc Inc | Ashland, MO | Installer (Level Advanced) | 36323 |
| Staats Excavating | Columbia, MO | Installer (Level Advanced) | 33305 |
| Sublett Trucking Llc | Clark, MO | Installer (Level Advanced) | 38067 |
| Sutton Excavating | Sturgeon, MO | Installer (Level Advanced) | 38183 |
| Sutton Excavating Llc | Sturgeon, MO | Installer (Level Basic) | 39294 |
| Tim Sublett Exc | Harrisburg, MO | Installer (Level Basic) | 36426 |
| Tru Built Contracting Mo Llc | Maysville, MO | Installer (Level Advanced) | 39359 |
| Turnbull Contracting, Llc | Bowling Green, MO | Installer (Level Advanced) | 38336 |
| Turnbull Contracting, Llc | Bowing Green, MO | Installer (Level Advanced) | 31558 |
| Twitchell Backhoe Service | Fulton, MO | Installer (Level Basic) | 34985 |
| Whalen Services, Llc | Auxvasse, MO | Installer (Level Basic) | 33949 |
94 companies in the Missouri DHSS registered OWTS installer list are based in Audrain County as of 2026-07-23. Companies based elsewhere in Missouri also commonly serve the county.
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