On February 13, 2019, EPA conducted a Combined Sewer System (CSS) and Sanitary Sewer System (SSS) Compliance Evaluation Inspection (CEI) of the Respondent's Yonkers Joint collection system and identified violations of the SPDES Discharge Permit, including failure to comply with effluent limits, failure to adequately inspect and maintain CSO regulators, failure to adequately document inspections, failure to properly operate and maintain all disposal facilities, failure to maximize in-system storage, Dry Weather Overflows, failure to inspect and maintain CSO outfall signs and for unpermitted SSO discharges.