🏞️ Montana’s Repeal of Numeric Nutrient Limits 🏞️

In October 2025, EPA approved MDEQ’s revisions under HB 664; formally repealing numeric nutrient criteria for nitrogen and phosphorus and affirming narrative nutrient standards while maintaining Clean Water Act goals.

Instead of fixed numeric limits, narrative standards describe desired conditions — for example, no excessive algae growth, no oxygen depletion, and protection of aquatic life.

📌 What this means:
🔹 Facilities with municipal or industrial discharges may see permit updates emphasizing site-specific evaluations over numeric thresholds.
🔹 Numeric limits are no longer in force for most wadeable streams and select segments of rivers (state waters only); narrative criteria now apply.
🔹 Monitoring and compliance will shift toward biological and condition-based indicators, rather than fixed numeric limits.
🔹 EPA retains oversight and can act if narrative criteria fail to protect designated uses.