Nitrate concentrations in urban streams at Rotorua are much higher than those in nearby rural streams. The loads of nitrogen are consistent with the loads discharged to septic tanks in the stream catchments. Phosphorus concentrations are no higher than in rural streams, and phosphorus loads in the streams are less than 2% of the load on the septic tanks. Nitrate in the streams is slowly decreasing now that the sewerage reticulation system is almost complete.