Monitoring of five dairy farming catchment streams in New Zealand shows they have high concentrations of N and P forms and faecal indicator bacteria. Suspended solids (SS) concentrations are sometimes high because of poor riparian management. Trend analysis and specific yields of N, P and SS for two streams that have been monitored for five years indicates that little change has occurred in water quality. However, improved water quality has been detected in the trends for two streams that have been monitored for 10 years, as a result of reductions in point sources and improved stock management (less intensive grazing and better stream bank fencing) that have taken place over the longer period. Surveys of farm management practices have been conducted at two-yearly intervals and best management practices are recommended for farming in each catchment, based on identified linkages between land use and water quality.