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Onsite Wastewater Treatment Systems (OWTS)
The St. Charles County Division of Building and Code Enforcement regulates Onsite Wastewater Treatment Systems (OWTS), often called septic tanks, in unincorporated areas of St. Charles County and in jurisdictions in which we contract. To determine the jurisdiction of your project area, please use the Permit Lookup Tool.
Regulation and Code Requirements
St. Charles County Building and Code Enforcement enforces the following regulations and codes:
| Title | Application | Reference Document | Local Adoption |
|---|---|---|---|
| Private Sewage Disposal Code of St. Charles County | All Onsite Wastewater Treatment Systems (OWTS) | 2015 International Private Sewage Disposal Code (IPSDC) | OSCCMo 500.300 |
| Residential Code of St. Charles County | Residential plumbing associated with OWTS | 2015 International Residential Code (IRC) including Appendices E, G, I, J, K, M, and P | OSCCMo 500.150 |
| Plumbing Code of St. Charles County | Commercial and multi-family residential plumbing associated with OWTS | 2015 International Plumbing Code (IPC) | OSCCMo 500.280 |
| Missouri Department of Health and Senior Services | All OWTS | Missouri Laws Governing OWTS (aka "The Green Book") | N/A |
| Onsite Wastewater Treatment System Inspector Business License | Inspection of systems at transfer of ownership | N/A | OSCCMo 626 |
| Onsite Wastewater Treatment System Installer Business License | Inspection of systems at transfer of ownership | N/A | OSCCMo 627 |
The Importance of OWTS
Sanitary waste generated from toilets, sinks, and other sources on properties must be treated and processed to prevent pollution and contamination of surface and groundwater—including sources of drinking water. Failure to properly treat this waste can result in illness, including death. For proper treatment, the waste must be processed by either a public treatment plant via public sewers, or—where access to a public sewer is not available—through an OWTS.
Minimum Requirements
St. Charles County has minimum local standards to protect people from sanitary waste. These standards include the installation of new systems, or portions of systems, and the repair of existing systems. In addition, the County has programs to ensure new property owners are assured the OWTS system servicing the property is operating properly, and a program to ensure existing systems are being properly maintained as to not impact adjacent properties or contaminate drinking water sources.