Registered OWTS installers in Missouri
Missouri’s roster of registered onsite wastewater treatment system installers covers 1,324 businesses across 113 counties. Pick a county to see who is based there.
Counties with the most registered owts installers
- Greene County224
- Christian County207
- Stone County194
- Camden County184
- Lawrence County176
- Barry County160
- Polk County153
- Taney County153
- Morgan County148
- Webster County148
- Jackson County139
- Johnson County139
- Miller County138
- Franklin County134
- Jefferson County134
Every county with registered owts installers
- Adair13
- Andrew38
- Atchison11
- Audrain83
- Barry160
- Barton50
- Bates71
- Benton118
- Bollinger41
- Boone130
- Buchanan54
- Butler28
- Caldwell47
- Callaway119
- Camden184
- Cape Girardeau36
- Carroll21
- Carter21
- Cass122
- Cedar85
- Chariton27
- Christian207
- Clark9
- Clay112
- Clinton75
- Cole112
- Cooper68
- Crawford60
- Dade122
- Dallas125
- Daviess35
- DeKalb48
- Dent36
- Douglas89
- Dunklin12
- Franklin134
- Gasconade57
- Gentry17
- Greene224
- Grundy13
- Harrison17
- Henry109
- Hickory99
- Holt17
- Howard59
- Howell38
- Iron50
- Jackson139
- Jasper106
- Jefferson134
- Johnson139
- Knox13
- Laclede93
- Lafayette95
- Lawrence176
- Lewis19
- Lincoln94
- Linn13
- Livingston19
- Macon35
- Madison50
- Maries52
- Marion28
- McDonald82
- Mercer8
- Miller138
- Mississippi8
- Moniteau71
- Monroe45
- Montgomery81
- Morgan148
- New Madrid15
- Newton102
- Nodaway20
- Oregon15
- Osage56
- Ozark66
- Pemiscot9
- Perry44
- Pettis96
- Phelps54
- Pike54
- Platte88
- Polk153
- Pulaski66
- Putnam8
- Ralls42
- Randolph64
- Ray75
- Reynolds29
- Ripley13
- Saline39
- Schuyler5
- Scotland8
- Scott33
- Shannon27
- Shelby24
- St. Charles131
- St. Clair62
- St. Francois92
- St. Louis
- St. Louis (city)
- Ste. Genevieve67
- Stoddard26
- Stone194
- Sullivan9
- Taney153
- Texas53
- Vernon47
- Warren113
- Washington96
- Wayne40
- Webster148
- Worth13
- Wright72
Where the roster is filed, and where the work happens
These records are organised by the address on the licence, and that address is not a service area. A Missouri licence is granted by Missouri DHSS and is valid across the state — the county tells you where the business is, not the limit of where they will go.
In practice a rural county showing two registered owts installers is rarely the real choice set. Every county page here lists its neighbours for exactly that reason.
Records as published August 26, 2026.