Wairoa River is the largest river in Hawke’s Bay. The predominant land use within the catchment is agricultural with sheep/beef farming and some dairying. There are two water quality sampling sites on the river - beside the ski club upstream from the highway bridge in the township and at the yacht club ramp in the estuary.
There are a number of discharges into the river with Frasertown Meats located upstream of the sampling site, and downstream discharges including Affco Wairoa and the municipal sewage discharge. Additionally, there are a number of stormwater drains which flow into the river, and both active and closed landfills near the mouth of the river. Elevated bacteria levels are generally observed after heavy and prolonged rainfall.