OOn December 11, 2023, Region 3 entered into four Administrative Orders on Consent with Horizon Land Management, LLC, ( Horizon ) and four of the Manufactured Home Communities ( MHCs ) it manages: Boone?s Estates MHC, LLC, Lyons Creek MHC, LLC, Maryland Manor MHC, LLC, and Patuxent MHC, LLC located in Ann Arundel County, Maryland. The Wastewater Treatment Plants at each MHC have had numerous exceedances since January 2019, malfunctioning equipment and infrastructure, lack of proper operation and maintenance, and missing or late flow reporting. Boone?s Estates MHC, LLC also has violations of visible foam and scum, and mishandling of sludge. Lyons Creek also had violations of visible foam and scum and an unauthorized discharge point. The Orders require each MHC to create an Operations and Maintenance manual with a Preventative Maintenance Plan, perform an Engineering Evaluation of each plant with recommendations to comply with permit effluent limitations and monitoring requirements, and a Corrective Action Plan with deadlines for repairing and replacing plant components. The Orders also require the MHCs to submit quarterly progress reports. The Maryland Department of the Environment was informed of and assisted with this enforcement matter. The MHC communities, located in Lothian and Harwood, Maryland, are potential EJ areas of concern.