State of the Environment (SoE) monitoring by Greater Wellington Regional Council (GWRC) in the Taratahi Groundwater Zone (GWZ), located south of the Waiohine River has reported elevated nitrate nitrogen (NO3-N) concentrations in shallow groundwater for a number of years.

GWRC routinely measures water quality at three sites in the area - two groundwater wells S26/0223 and S26/0299 and one spring fed stream (Lowes Bush) that is monitored as part of the Surface Water SoE Programme. Nitrate-nitrogen concentrations have ranged between 1.7 and 12.5 mg/L in the wells and between 2.1 and 6.2 mg/L in the Lowes Bush spring.