EPA released draft ambient water quality criteria recommendations for lakes and reservoirs in May 2020. The draft uses stressor-response models based on new water quality data to derive chlorophyll-a, phosphorus, and nitrogen criteria. It recommends chlorophyll-a criteria ranges for different lake depths to protect aquatic life. Potential criteria derived from models show illustrative phosphorus and nitrogen concentrations corresponding to chlorophyll-a levels. The document's approach raises questions about the validity of nationwide models, adjustment to Texas conditions, and linking chlorophyll-a to nutrient criteria. State regulators will determine how to respond.