We develop an integrated assessment model for spatially simulating water quality and social welfare from linked ecosystem services that extends prior modeling by incorporating a broader suite of pollutants than conventionally measured factors like phosphorus and nitrogen. Beyond demonstrating the feasibility of such a model, we provide guidance on the impact of omitting or holding constant relevant pollutants and their effect on estimates of water quality and willingness to pay. Applying the model to Narragansett Bay, we find that recent wastewater treatment upgrades and a legacy network of dams are providing millions in annual value to adjacent residents.