Turbidity levels in the New Haven River increase downstream but are generally low and below the state standard. However, at times of high flow and runoff, turbidity levels reach very high levels, greatly exceeding the state standard near its mouth. Phosphorus concentrations in the New Haven River are generally low, increasing downstream as do turbidity levels, indicating that phosphorus in the river is mainly associated with suspended sediment. There is currently no Vermont water quality in-stream standard for phosphorus.
Total nitrogen concentrations in the New Haven River have proven to be low and well below the Vermont State Standard for nitrate.