Water pollution is widely considered to be one of the most important environmental issues facing New Zealand. Waikato region residents have reported that water pollution is easily their most important environmental concern in each of four attitude surveys conducted by Environment Waikato. Technical and regulatory mechanisms to reduce water pollution, especially non-point source pollution from agriculture are the focus of an intensive research effort both in New Zealand and internationally. This work should assist farmers and policy makers to identify the most cost effective options for achieving any given improvement in water quality. Research described in this paper aims to complement existing research projects by developing appropriate methodology for valuation of water quality improvements in New Zealand. It is envisaged that this type of information will inform the policy process by allowing decision makers to consider both the costs and the benefits of different levels of water quality improvements. This paper describes the first phase focussed on the Karapiro catchment which used focus groups and choice modelling in order to understand and quantify the value of water quality improvements in the catchment.