Last Updated 08/24/2026
Excerpts from Stormwater Ordinance 3580 Chapter 13-27
13.27.300 Requirement to Control and Reduce Storm Water Pollutants
A. The City’s Storm Water Management Plan and Storm Water Specifications and Design Standards outline appropriate BMPs to control the volume, rate, and potential of pollutants in storm water runoff from new development and redevelopment projects as may be appropriate to minimize the generation, transport, and discharge of pollutants.
B. Any owner or operator engaged in activities or operations which will or may result in pollutants entering storm water, the MS4, or state waters shall implement BMPs to the maximum extent practicable to provide protection from discharge into the MS4. BMPs shall be provided and maintained at the owner or operator’s expense. The Public Works Director shall have the authority to require the installation, operation, maintenance, and/or replacement of BMPs as well as the authority to order the removal of temporary BMPs.
13.27.310 Requirement to Monitor and Analyze
The City may require any owner or operator engaged in any activity or owning or operating any facility which may cause or contribute to storm water pollution, illicit discharges, or non-stormwater discharges to the MS4 or state waters to undertake, at the owner or operator’s expense, monitoring and analysis by a state certified laboratory pursuant to the provisions of this chapter and furnish those reports to the Public Works Department as deemed necessary to determine compliance with this chapter as well as the Storm Water Specifications and Design Standards
View State Page
Frequently Asked Questions
Who is responsible for implementing BMPs on a Missoula property?
Any owner or operator engaged in activities that will or may result in pollutants entering stormwater, the MS4, or state waters must implement best management practices to the maximum extent practicable to prevent discharge into the system. These BMPs must be provided and maintained at the owner or operator’s own expense.
Can the City of Missoula require changes to a property's stormwater BMPs?
Yes. The Public Works Director has authority to require the installation, operation, maintenance, or replacement of BMPs on a property, and can also order the removal of temporary BMPs when appropriate.
Can Missoula require a property owner to monitor and test their stormwater discharge?
Yes. The city can require an owner or operator whose activities or facility may cause or contribute to stormwater pollution, illicit discharges, or non-stormwater discharges to the MS4 or state waters to conduct monitoring and analysis through a state-certified laboratory, at their own expense, and submit those reports to the Public Works Department to verify compliance.
Where does Missoula's stormwater design guidance come from?
The city’s Storm Water Management Plan and Storm Water Specifications and Design Standards outline the BMPs expected for new development and redevelopment projects, aimed at controlling the volume, rate, and pollutant potential of stormwater runoff before it leaves the site.
The information on this page is provided for general informational purposes only and is not legal advice. Regulations change frequently — AQUALIS makes no warranty as to the accuracy or completeness of this content, and any reliance on it is at your own risk. Consult a qualified professional or your local regulatory authority to confirm requirements applicable to your specific property.
