Environmental Rules in Billings, MT (2026)
4 verified environmental rules for Billings, Montana, sourced directly from the municipal code and official government pages.
Verified from official government sources
Stormwater Management
Billings operates an MS4 stormwater system under EPA NPDES Phase II permit. Property owners cannot discharge non-stormwater pollutants to streets, gutters, ditches, or storm drains feeding the Yellowstone River.
Stormwater discharge and illicit connection rules
Some RestrictionsErosion Control
Construction on the Billings Rims, Sacrifice Cliff terraces, and steep draws above the Yellowstone Valley must install erosion controls before grading to keep sediment out of storm drains and waterways.
Erosion and sediment control on Rims and slopes
Some RestrictionsFlood Zones
Billings regulates construction within the FEMA-mapped Yellowstone River floodplain through floodplain permits, elevation requirements, and prohibitions on fill or structures that increase flood heights downstream.
Yellowstone River floodplain construction limits
Heavy RestrictionsVehicle Idling Restrictions
Montana has no statewide diesel anti-idling rule, and Billings does not impose a general idling ban. Air quality near the ExxonMobil refinery, CHS Laurel, and rail yards is monitored under federal Clean Air Act standards.
Diesel idling and ExxonMobil refinery air quality
Few RestrictionsLooking for Yellowstone County county-wide rules?
County ordinances apply to unincorporated areas and may supplement Billings city rules.
Environmental Rules in Yellowstone County →