Missouri Department of Natural Resources inspectors found that a wastewater lagoon serving the Byrnes Mill Farms mobile home park violated state water quality standards after wastewater was discharged into a tributary of the Big River. The findings have renewed attention on wastewater management, regulatory compliance and protection of one of eastern Missouri’s most popular recreational waters.
JEFFERSON COUNTY, MO – August 3, 2026 (STL.News) The Missouri Department of Natural Resources (DNR) has determined that a wastewater lagoon serving the Byrnes Mill Farms mobile home park in Jefferson County violated Missouri water quality standards after wastewater was discharged into a tributary of the Big River, according to state inspection findings. The agency classified the facility as being in significant noncompliance with the Missouri Clean Water Law following an inspection of the site.
The findings have renewed attention on wastewater management in the Big River watershed, a popular destination for fishing, floating, kayaking and other outdoor recreation. While nearby residents had complained for months about odors associated with the lagoon, the DNR’s investigation focused on documented permit violations and their impact on a tributary that flows into the Big River.
State Inspectors Documented Water Quality Problems
According to the DNR inspection summarized in public reporting, inspectors observed gray, turbid water leaving the lagoon’s discharge point and entering a tributary of the Big River. They also documented white biological growth downstream and determined that the discharge violated Missouri water quality standards. Water sampling indicated impacts to dissolved oxygen levels, an important measure of stream health that affects fish and other aquatic life.
The DNR’s publicly reported findings conclude that wastewater discharged from the lagoon polluted a tributary of the Big River. The agency’s findings do not state that untreated sewage was discharged directly into the Big River during this incident. That distinction is important because official findings should not be expanded beyond what regulators documented.
Resident Complaints Preceded the Inspection
Residents living near the mobile home park had previously complained about persistent odors coming from the lagoon and questioned whether the wastewater treatment system was operating properly. Those complaints prompted additional public attention and were followed by the DNR inspection that documented the permit violations.
Previous Clean Water Act Litigation
The wastewater lagoon has previously been the subject of federal litigation.
In 2020, Missouri Confluence Waterkeeper filed a lawsuit under the federal Clean Water Act alleging that Byrnes Mill Farms repeatedly violated its discharge permit by releasing pollutants, including ammonia and E. coli, into waters connected to the Big River watershed. The lawsuit was resolved through a settlement and did not result in a judicial finding of liability after trial. The settlement included provisions intended to improve wastewater management and support restoration work benefiting the watershed.
The Importance of the Big River
The Big River extends approximately 145 miles through eastern Missouri before joining the Meramec River. It is widely used for recreational activities including canoeing, kayaking, fishing, and swimming.
Because tributaries feed into larger waterways, pollution affecting smaller streams can ultimately influence the health of the broader watershed. Protecting tributaries is therefore an important component of maintaining water quality throughout the Big River system.
Regulatory Oversight Continues
Wastewater treatment facilities operating in Missouri must comply with state operating permits issued under the National Pollutant Discharge Elimination System (NPDES). Those permits establish discharge limits and operating requirements intended to protect rivers, streams and other waters of the state. Missouri law authorizes the DNR to investigate violations and take enforcement actions when facilities fail to comply with permit requirements.
The Byrnes Mill Farms facility remains subject to DNR oversight. Publicly available reports state that regulators documented violations and classified the facility as significantly noncompliant. Any additional enforcement actions would be determined by the DNR through its established regulatory process.
Looking Ahead
The DNR’s findings highlight the importance of maintaining wastewater infrastructure that protects Missouri’s rivers and streams.
The verified public record shows that state inspectors concluded wastewater discharged from the Byrnes Mill Farms lagoon polluted a tributary of the Big River and violated Missouri water quality standards. Those findings have renewed public attention on wastewater compliance and the protection of one of eastern Missouri’s most heavily used recreational waters.
