Montana Stormwater-Municipalities regulations & environmental compliance analysis

Montana Stormwater-Municipalities: What you need to know

Governing Law and Regulations

Montana Pollutant Discharge Elimination System (MPDES) permits: Administrative Rules of Montana (ARM) 17.30.1301 to 17.30.1387

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MPDES stormwater discharges: ARM 17.30.1101 to 17.30.1117

Municipalities: ARM 17.30.1111

Stricter requirements: ARM 17.30.1111(11)

Regulatory Agencies

Montana Department of Environmental Quality (DEQ) Permitting and Compliance Division Water Protection Bureau

U.S. Environmental Protection Agency (EPA) Region 8

Comparison: State vs. Federal

Rules. Montana is authorized by the U.S. Environmental Protection Agency (EPA) to administer the National Pollutant Discharge Elimination System (NPDES) permit program (known as the Montana Pollutant Discharge Elimination System (MPDES)) and to issue individual and general permits for stormwater discharges associated with municipal separate storm sewer systems (MS4s). The state generally follows the federal requirements for stormwater permits but has state-specific application forms and has fees for stormwater permits. See the national section STORMWATER—MUNICIPALITIES for more information on the federal MS4 stormwater requirements.

Administration and enforcement. The Montana Department of Environmental Quality's (DEQ) Water Protection Bureau administers and enforces the MPDES permit program for stormwater discharges associated with MS4s in Montana. The DEQ issued an updated general permit (MTR040000) for stormwater discharges from MS4s. The permit goes into effect on January 1, 2017, and expires December 31, 2021.

State Requirements


ARM 17.30.1111

Owners or operators of small MS4s must apply for authorization under an MPDES permit. Small MS4s must complete an application that includes:

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