Poor quality wastewater effluent discharged to surface water poses a threat to humans and the environment. The research examines wastewater effluent quality in the Free State Province, South Africa, concentrating on an in-depth evaluation of the impact thereof on surface water across the Mangaung Metropolitan Municipality (MMM) serving Bloemfontein, the capital city of the Free State. A physicochemical analysis of the influent and effluent from three of MMM's thirteen conventional wastewater treatment plants (WWTPs) was employed. Influent and effluent samples were determined experimentally for chemical oxygen demand (COD) and oxygen absorbed (OA). Furthermore, a seasonal surface water sampling schedule was implemented over a year to evaluate the impact of wastewater discharged into it. Key parameters like pH, electrical conductivity (EC), and total dissolved solids (TDS) were given priority. HANNA's state-of-the-art HI 98195 and HI 98193 probes facilitated data collection. The results were compared with the wastewater discharge standards of South Africa to determine compliance. The Sterkwater WWTP had an average COD of 94.7 mg/l. The North-East and Botshabelo plants had an average COD of 143.7 and 161.8 mg/l, respectively. The high pH levels, varying electrical conductivity, and total dissolved solids pose risks to public health. These anomalies are due to intermittent power outages, financial limitations, scarcity of suitably trained staff, and substandard maintenance procedures affecting the wastewater treatment facilities. These fundamental issues demand prompt attention and resolution to effectively eradicate the incidence of poor-quality effluents discharged into surface waters in the province and country.