Agricultural conservation practices have long been promoted for resource conservation and environmental benefits. We examine cover crop adoption with ambient water quality to estimate the influence this soil health practice hashad on non-point source pollution from agriculture. We use remotely sensed data on practice adoption and control for the direction of hydrological flow, weather, and land use to econometrically measure the impact of cover cropping on total Nitrogen concentrations in surface water while controlling for pollutant inflow from upstream. The spatial unit of analysis is a HUC8, also examined in other recent research using different treatment variables to explain variation in surface water quality. Our results provide novel estimates based on observed data that can be compared to more common biophysical simulations of conservation practice effectiveness.