The user-pays principle encourages use of a water tariff structure that incorporates pollution and/or depletion of a water resource because that water represents a capital resource base. Development of a tool that models variability of surface raw water quality in order to predict cost of treatment thus makes economic sense. This paper forms the backbone for an on-going doctoral study in South Africa's Upper and Middle Vaal Water Management Areas (U&MVWMAs) of the Vaal River (VR). Specific objectives of the overall research are; to carry out pollutant tracer hydrochemistry of specific reaches of the U&MVWMAs including producing an integrated ecological functionality for the whole study area, and to develop a tool that models the variability of surface raw water quality using surface raw water tariffs and water quality data for years 2003–2008. This paper concluded that downstream water boards (WBs) paid a higher water resources management charge (WRMC) for more polluted raw water than upstream WBs. It was recommended that a quality-cost model be incorporated at tier1 of the cost chain for water services to ensure fairness of service delivery and spread of burden to consumers.
Keywords: cost of treatment, pollutant tracer, quality-cost model, raw water quality, tariff structure, Vaal River