Missouri licensed septic contractors
Missouri publishes its septic licensing through the Missouri DHSS. This is every record it holds, as pages you can navigate: 1,483 businesses and 1,827 individually licensed onsite professionals across 113 of 115 counties.
Registered OWTS installers
A business the state has licensed for the work that installs onsite wastewater treatment systems.
Registered onsite soil evaluators
A business the state has licensed for the work that evaluates soil to decide what kind of system a site can take.
Registered onsite wastewater professionals
An individual, not a company: someone who holds a Missouri onsite wastewater registration personally.
Missouri counties with the most licensed businesses
- Greene County267
- Christian County247
- Stone County232
- Camden County225
- Lawrence County206
- Taney County189
- Barry County187
- Webster County183
- Morgan County179
- Polk County176
- Miller County175
- Jefferson County159
- Franklin County157
- Johnson County156
- Dallas County154
- Boone County153
- Jackson County153
- St. Charles County149
- Dade County144
- Callaway County143
All 115 Missouri counties
The number is how many licensed businesses give that county as their address. Greyed counties have none — 2 of the 115.
- Adair18
- Andrew40
- Atchison13
- Audrain101
- Barry187
- Barton65
- Bates80
- Benton139
- Bollinger48
- Boone153
- Buchanan59
- Butler33
- Caldwell51
- Callaway143
- Camden225
- Cape Girardeau43
- Carroll27
- Carter26
- Cass139
- Cedar98
- Chariton33
- Christian247
- Clark11
- Clay126
- Clinton83
- Cole141
- Cooper85
- Crawford71
- Dade144
- Dallas154
- Daviess38
- DeKalb51
- Dent47
- Douglas107
- Dunklin15
- Franklin157
- Gasconade70
- Gentry20
- Greene267
- Grundy17
- Harrison18
- Henry122
- Hickory115
- Holt19
- Howard70
- Howell46
- Iron61
- Jackson153
- Jasper127
- Jefferson159
- Johnson156
- Knox15
- Laclede131
- Lafayette102
- Lawrence206
- Lewis21
- Lincoln111
- Linn18
- Livingston24
- Macon41
- Madison61
- Maries65
- Marion31
- McDonald96
- Mercer11
- Miller175
- Mississippi12
- Moniteau83
- Monroe54
- Montgomery100
- Morgan179
- New Madrid20
- Newton119
- Nodaway23
- Oregon20
- Osage72
- Ozark80
- Pemiscot12
- Perry55
- Pettis108
- Phelps72
- Pike65
- Platte98
- Polk176
- Pulaski93
- Putnam11
- Ralls48
- Randolph75
- Ray86
- Reynolds37
- Ripley18
- Saline45
- Schuyler6
- Scotland9
- Scott40
- Shannon33
- Shelby28
- St. Charles149
- St. Clair72
- St. Francois108
- St. Louis
- St. Louis (city)
- Ste. Genevieve83
- Stoddard34
- Stone232
- Sullivan12
- Taney189
- Texas66
- Vernon54
- Warren133
- Washington114
- Wayne48
- Webster183
- Worth14
- Wright93
How Missouri regulates septic work
Missouri registers the individual installer and records the counties they serve. Your local health authority permits the system itself, and in some counties runs its own additional requirements on top.
Registrations carry an expiration date, shown on every listing. The state republishes the dataset as registrations change.
Missouri licenses people as well as businesses. The individual licences — registered onsite wastewater professionals — belong to a named professional, and we list them on county pages rather than giving each person a page of their own.
Records as published August 26, 2026.