Water

The federal Clean Water Act requires DEQ to assess Montana’s water quality and prepare a report every two years. The Montana Water Quality Report and List of Impaired Waters (known as the Integrated Report) combines reporting information for the Clean Water Act Section 305(b) assessment of water bodies and the Section 303(d) list of water bodies that do not meet water quality standards. Water bodies not meeting standards need pollution reduction studies, called Total Maximum Daily Loads (TMDLs). TMDLs also include plans to improve water quality to eventually meet standards.

When assessing surface water quality in Montana, DEQ is guided by the Beneficial Use Assessment Method for Montana’s Surface Waters. This document describes the framework used to assess state waters and to make the beneficial use support and water quality impairment decisions that are presented in the Water Quality Integrated Report.

DEQ assesses whether state surface waters are meeting applicable water quality standards for specific water quality characteristics, or parameters. If a waterbody is not meeting one or more water quality standards, DEQ considers the waterbody impaired and adds it to Montana’s list of impaired waters in the Water Quality Integrated Report. DEQ develops parameter-specific assessment methods which present the required data, analyses, and decision frameworks used to make these parameter-specific impairment listing decisions.

These documents and supporting files constitute the State of Montana's final Water Quality Integrated Report submission to the U.S. EPA for the given reporting cycle. This includes both the Section 303(d) List and Section 305(b) Report as required under the federal Clean Water Act.

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Final Water Quality Integrated Reports

Montana classifies its waterbodies according to present and future beneficial uses they are expected to support (§ 75-5-301, MCA). This layer displays surface water bodies in Montana contained the NHD and their associated use class.

Go To The Use Class Map

Montana’s surface-water-use classification system bases class assignments primarily on water temperature, fish, and associated aquatic life. Each class has an associated beneficial use. A waterbody supports its beneficial uses when it meets the Water Quality Standards (WQS) established to protect those uses. A waterbody is impaired when any one of its WQS are violated.

Determining whether or not a specific use is supported is independent of all other designated uses. For example, a waterbody may partially support aquatic life because of excess nutrients, not support drinking water because of arsenic, but fully support agriculture and industrial uses. Classes A, B, and C are the three most common. Class I is a temporary category assigned to three streams that were grossly impaired when the system was established. Classes A-Closed and A-1 are considered high quality, the principal beneficial use of which is public water supply. The A-Closed class may invoke watershed protection and use restrictions to protect drinking water. Classes B and C each have subsections according to whether they support coldwater or warmwater aquatic life. B-1, B-2, C-1, and C-2 support coldwater aquatic life; B-3 and C-3 support warmwater aquatic life. B and C waters have nearly identical use classifications, but B waters specify drinking water as a beneficial use whereas C waters do not. C-3 streams are suitable for warmwater aquatic life and recreation. Because these streams often contain naturally high total dissolved solids (salinity), their quality is marginal for drinking and agricultural and industrial uses.

In August 2003 Montana added four additional classes: D, E, F, and G. The classes include ephemeral streams (E-1, E-2), ditches (D-1, D-2), seasonal or semi-permanent lakes and ponds (E-3, E-4, E-5), and waters with low or sporadic flow (F-1). G-1 waters must be maintained for watering wildlife and livestock and supporting secondary contact recreation and aquatic life, not including fish. These waters are marginally suitable for irrigation after treatment or with mitigation measures and includes “holding water” from coal bed methane development. Note: The classification system designated uses for waterbodies as present at the time of classification in 1955.

Waterbodies may now have other realized uses that are not officially designated. In such cases, a waterbody may be reclassified to officially recognize these other uses. Conversely, designated uses cannot be removed from a waterbody without a formal Use Attainability Analysis and approval under rulemaking by the Montana Board of Environmental Review. Streams forming the boundary of Indian Reservations are coded as State of Montana (SOM) waters for practical reasons related to enforcing Federal and Montana water quality standards. In some cases meanders, canals, and ditches that transect the boundary and then reconnect with a border stream are also coded as SOM waters even when they are located in part or entirely within the Indian Reservation. As a result of this coding protocol,

If you use the "select by location" procedure to identify streams that are completely within one of the reservations, the resulting selected records may include a small number of streams coded as SOM in the "Authority Entity" field. This is not a mistake and needs to be kept in mind when interpreting selection results. Streams that are not parallel to or located on a border but that cross into and are entirely within an Indian Reservation retain the use class as designated by the ARM description for the watershed they are part of but they are designated as "Not State Jurisdiction" or NSJ in the event table's "Jurisdiction" field and the name of the tribe is recorded in the "Authority Entity" field. The name of the reservation is recorded in the "Area Name" field. Streams that are not parallel to or located on a border but that cross into and are entirely within national parks, wilderness areas or primitive areas are assigned a use class of A-1 as specified by ARM Title 17 Chapter 30 Subchapter 614. The name of the park, primitive area, or wilderness area is recorded in the "Area Name" field of the event table. As a consequence, a stream crossing a border will likely have different use classes on either side of the border.

National Drinking Water Regulations

• National Primary Drinking Water Regulations
• National Secondary Drinking Water Regulations

Public Water and Sewage Systems

• MCA Title 75 Chapter 6: Public Water Supplies, Distribution, and Treatment
• Public Water and Sewer Plans
• Public Water Supply Requirements
• Cross Connections in Drinking Water Supplies

Consumer Confidence Report Rule

• Consumer Confidence Report Rule
• Consumer Confidence Reports Regulation

Lead and Copper Rule

• Lead and Copper Rule Summary-EPA
• Control of Lead and Copper Regulations
• Sampling Responsibilities
• Testing, Sampling, Reporting Requirements

Disinfectant Byproducts Rule

• Disinfectants and Disinfection Byproducts Rules Summary-EPA
• Stage 2 Disinfection Byproducts Requirements

Montana Chlorination Rule

• Sampling and Reporting Responsibilities
• Control Tests
• Acceptable methods and levels of disinfection

Surface Water Treatment Rule

• Surface Water Treatment Rule Summary - EPA
• Surface Water Treatment Rule Summary - DEQ

Total Coliform Rule

• Revised Total Coliform and Total Coliform Rules Summary - EPA
• Revised Total Coliform Rule
• Sampling Responsibilities

Water Treatment Operators

• Arsenic Rule Compliance for Water System Operators - EPA
• Water Treatment Plant Operators Act
• Classification of Systems
• Certification of Operators
• Examinations
• Experience and Education
• Certified Operators; Exceptions
• Fees
• Continuing Education Requirements
• Disciplinary Actions
• Approved Training Providers

Drinking Water State Revolving Fund

• MCA Title 75 Chapter 6 Part 2: Drinking Water State Revolving Fund Act
• Drinking Water State Revolving Fund Rules

• Groundwater Rule (GWR)
• Protecting Groundwater Quality in Montana
• Montana Groundwater Rules
• Montana Groundwater Quality Standards (DEQ-7)
• Montana Water Quality Report
• EPA Groundwater Rule Summary
• EPA Groundwater Rule Quick Reference Guide

• Water Quality Permits Statute
• Montana Groundwater Pollution Control System (MGWPCS) Rules
• 401 Certification
• Nutrient Trading
• Permit Application, Degradation Authorization, and Annual Fees
• Stormwater Discharges

• Subchapter 17.36.1 Subdivision Application and Review
• 17.36.102 Application- General
• 17.36.103 Application - Contents
• 17.36.104 Application - Lot Layout Document
• Subchapter 17.36.6 Subdivision Waivers and Exclusions
• 17.36.320 Sewage Systems - Design and Construction

Nondegradation

• 17.30.705 Nondegradation Policy - Applicability and Level of Protection
• 17.30.715 Criteria for Determining Nonsignificant Changes in Water Quality

Stormwater

• 17.36.310 Storm Drainage

Wastewater System and Operators

• Classification of Systems
• Certification of Operators
• Examinations
• Experience and Education
• Certified Operators; Exceptions
• Fees
• Continuing Education Requirements
• Disciplinary Actions
• Approved Training Providers

Water Pollution Control State Revolving Fund

• Water Pollution Control State Revolving Fund

• Classification and Standards
• Monitoring-Water Quality Assessment Listing
• Development and Implementation of TMDL

• Water Quality Standards
• Mixing Zones in Surface and Groundwater

Nutrient Variance

• Short Term Standards for Turbidity

• Clean Water Act
• Safe Drinking Water Act
• Montana Water Quality Regulation Guidance

Use EPA's Enforcement and Compliance History Online website to search for facilities in your community to assess their compliance with environmental regulations. You can use ECHO to:

• Search for Facilities
• Investigate Pollution Sources
• Search for EPA Criminal and Civil Enforcement Cases
• Examine and Create Enforcement-Related Maps
• Analyze Trends in Compliance and Enforcement Data
• Explore your State's Performance

Please Note: The data online is provided as a public resource and does not always reflect the most up to date information.

Private water wells and septic systems require homeowners to take more control of their water quality. Well and septic owners have a responsibility to themselves, their families, and their neighbors to protect ground water from contamination and to ensure that water systems provide good quality drinking water.

Stay Well by Checking Your Well

Don’t Wish for Safe Water…Test for It!

What to do After a Flood

Maintaining a Private Septic System