| Company | Location | Certifications | License # |
|---|---|---|---|
| 3t Plumbing Llc | Rosebud, MO | Installer (Level Basic) | 38589 |
| Afp Development & Construction | Salem, MO | Installer (Level Basic) | 39109 |
| Appraisal & Building Solutions Llc | St James, MO | Installer (Level Basic) | 38834 |
| Backhoe Services Unlimited | Villa Ridge, MO | Installer (Level Advanced) | 37992 |
| Bauche Contracting Llc | Washington, MO | Installer (Level Basic) | 39096 |
| Bo'S Home Inspections | — | Installer (Level Basic) | 39230 |
| Bo'S Home Inspections And Services Llc | Rolla, MO | Installer (Level Advanced) | 39188 |
| Brady Wilson | Rolla, MO | Installer (Level Basic) | 38782 |
| Central Mesa Holdings Llc | Manchester, MO | Installer (Level Basic) | 38925 |
| Chapman Contracting | Saint Clair, MO | Installer (Level Advanced) | 32521 |
| Cmk Land Management | Union, MO | Installer (Level Basic) | 38936 |
| Derek Thompson | — | Installer (Level Advanced) | 39557 |
| Double R Plumbing And Contracting | Potosi, MO | Installer (Level Advanced) | 39140 |
| Drennen Excavating And Flat Work | — | Installer (Level Advanced) | 38041 |
| Figler Excavating Inc | Sullivan, MO | Installer (Level Advanced) | 36016 |
| Freedom Dirt Works Llc | Newburg, MO | Installer (Level Basic) | 38769 |
| Girdner Contracting Llc | Villa Ridge, MO | Installer (Level Advanced) | 34490 |
| Hickinbotham Realty | St Clair, MO | Installer (Level Basic) | 39061 |
| Hillside Enterprises | Cuba, MO | Installer (Level Basic) | 38760 |
| J Wyatt Contracting | Dittmer, MO | Installer (Level Advanced) | 30279 |
| J&M Excavating Services Llc | Hermann, MO | Installer (Level Basic) | 38591 |
| Jarvis Plumbing | Potosi, MO | Installer (Level Basic) | 36757 |
| Jay Rice Contracting | St. Clair, MO | Installer (Level Advanced) | 31340 |
| Justin Murphy | — | Installer (Level Basic) | 39115 |
| Kaysinger Liquid Waste | Cuba, MO | Installer (Level Basic) | 39273 |
| Kaysinger Liquid Waste Llc | Cuba, MO | Installer (Level Advanced) | 30124 |
| Land Co | High Ridge, MO | Installer (Level Advanced) | 39405 |
| Lynch Excavating & Trucking Llc | St James, MO | Installer (Level Advanced) | 30297 |
| Matt Girardier Excavating | St Clair, MO | Installer (Level Advanced) | 32259 |
| Mc Plumbing & Excavating Llc | Labadie, MO | Installer (Level Basic) | 37928 |
| Missouri Septic & Drain Management | Salem, MO | Installer (Level Basic)Installer (Level Advanced) | 38533 |
| Newshu Contracting Llc | Lonedell, MO | Installer (Level Basic) | 39335 |
| Parker Home Inspections | Rolla, MO | Installer (Level Basic) | 38880 |
| Parker Home Inspections Llc | Rolla, MO | Installer (Level Basic) | 38886 |
| Pj Myers Hauling & Excavating, Llc | Cuba, MO | Installer (Level Advanced) | 32059 |
| Pooles Septic System | Mineral Point, MO | Installer (Level Advanced) | 35956 |
| Pooles Septic System | Mineral Point, MO | Installer (Level Advanced) | 37891 |
| Pooles Septic Systems | Mineral Point, MO | Installer (Level Advanced) | 32407 |
| Reliable Excavating Llc | Saint James, MO | Installer (Level Basic) | 35698 |
| Reliable Septic & Portable Toilet | Hermann, MO | Installer (Level Basic) | 39184 |
| Riehl Excavation & Hauling Llc | Rolla, MO | Installer (Level Basic) | 38780 |
| Rock Of Ages | Cuba, MO | Installer (Level Basic) | 39300 |
| Ronnie'S Dirt Work | Steelville, MO | Installer (Level Basic) | 38519 |
| Second Nature Excavation And Hardscapes | New Haven, MO | Installer (Level Advanced) | 39370 |
| Septic Services Inc | — | Installer (Level Advanced) | 37146 |
| Septic Services Inc. | Union, MO | Installer (Level Advanced) | 30097 |
| Septic Services, Inc. | Union, MO | Installer (Level Advanced) | 38010 |
| Septic Services, Inc. | Union, MO | Installer (Level Advanced) | 38009 |
| Show Me Soils | Lonedell, MO | Installer (Level Basic) | 37830 |
| Show Me Soils | St. Clair, MO | Installer (Level Advanced) | 35758 |
| Strothkamp Excavating Llc | Sullivan, MO | Installer (Level Advanced) | 37019 |
| Unnerstall Contracting Co., Ltd | Pacific, MO | Installer (Level Advanced) | 33452 |
| Wagner Tree Trimming & Trenching | Lonedell, MO | Installer (Level Advanced) | 31312 |
| Wiese Property Improvements | Sullivan, MO | Installer (Level Advanced) | 38013 |
| William Hovis | — | Installer (Level Basic) | 39491 |
55 companies in the Missouri DHSS registered OWTS installer list are based in Crawford County as of 2026-07-23. Companies based elsewhere in Missouri also commonly serve the county.
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