Water

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.

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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• Addendum to the Final 2020 Water Quality Integrated Report
• Final 2020 Water Quality Integrated Report
• Appendix A - Impaired Waters
• Appendix B - Waters in Need of TMDLs
• Appendix C - Waters with Use Support Assessments
• Appendix D - Causes Delisted
• Appendix E - Beneficial Use Support Changes
• Appendix F - Approved TMDLs
• Appendix G - Monitoring Schedule
• Appendix H - Waters That Changed Reporting Categories
• Appendix I - Changes Made in the Course of Data Management/QA Activities
• Appendix J - Comments and Responses
• EPA Approval Letter for Addendum
• EPA Approval Letter
• Addended 303(d) List (text format)
• Addended 303(d) List (Excel format)
• GIS data download

• Final 2018 Water Quality Integrated Report
• Appendix A - Impaired Waters
• Appendix B - Waters in Need of TMDLs
• Appendix C - Waters with Use Support Assessments
• Appendix D - Causes Delisted
• Appendix E - Beneficial Use Support Changes
• Appendix F - Approved TMDLs
• Appendix G - Monitoring Schedule
• Appendix H - Waters That Changed Reporting Categories
• Appendix I - Changes Made in the Course of Data Management/QA Activities
• Appendix J - Comments and Responses
• EPA Approval Letter
• 303(d) List (text format)
• 303(d) List (Excel format)
• GIS data download

• Final 2016 Water Quality Integrated Report
• Appendix A - Impaired Waters
• Appendix B - Waters in Need of TMDLs
• Appendix C - Waters with Use Support Assessments
• Appendix D - Causes Delisted
• Appendix E - Beneficial Use Support Changes
• Appendix F - Approved TMDLs
• Appendix G - Monitoring Schedule
• Appendix H - Waters That Changed Reporting Categories
• Appendix I - Changes Made in the Course of Data Management/QA Activities
• EPA Approval Letter
• 303(d) List (excel format)
• 303(d) List (text format)
• GIS data download

• Quick Facts about the 2014 Integrated Report
• 2014 Integrated Report Executive Summary
• Final 2014 Water Quality Integrated Report
• Appendix A - Impaired Waters
• Appendix B - Waters in Need of TMDLs
• Appendix C - Waters with Use Support Assessments
• Appendix D - Causes Delisted
• Appendix E - Beneficial Use Support Changes
• Appendix F - Approved TMDLs
• Appendix G - Monitoring Schedule
• EPA Approval Letter
• 303(d) List (excel format)
• 303(d) List (text format)
• GIS data download

• 2012 Integrated Report
• Appendix A - Impaired Waters
• Appendix B - Waters in Need of TMDLs
• Appendix C - Waters with Use Support Assessments
• Appendix D - Causes Delisted
• Appendix E - Beneficial Use Support Changes
• Appendix F - Approved TMDLs
• Appendix G - Monitoring Schedule
• Attachment 1 - Final Assessment Method
• EPA Approval Letter
• 303(d) List (excel format)
• 303(d) List (text format)

• 2010 Integrated Report
• Appendix A - Impaired Waters
• Appendix B - Waters in Need of TMDLs
• Appendix C - Waters with Use Support Assessments
• Appendix D - Causes Delisted
• Appendix E - Beneficial Use Support Changes
• Appendix F - Approved TMDLs
• Errata
• EPA Approval Letter
• 303(d) List (excel format)
• 303(d) List (text format)

• 2008 Integrated Report
• Appendix A - Impaired Waters
• Appendix B - Waters in Need of TMDLs
• Appendix C - Waters with Use Support Assessments
• Appendix D - Causes Delisted
• Appendix E - Beneficial Use Support Changes
• Appendix F - Approved TMDLs
• Appendix G - Monitoring Schedule
• Appendix H - Cycle First Listed Corrections
• EPA Approval Letter
• 303(d) List (excel format)

• 2006 Integrated Report
• Appendix A - Waters Re-assessed during 2006 cycle
• Appendix B - Waters with Use Support Assessments
• Appendix C - Causes Delisted
• Appendix D - Beneficial Use Support Changes
• Appendix E - Monitoring Schedule
• Appendix F - TMDL Priority Schedule
• Appendix G - Approved TMDLs
• Appendix H.1 - Cat 4A Impaired Waters
• Appendix H.2 - Cat 4C Impaired Waters
• Appendix H.3 - Cat 5 Impaired Waters
• EPA's Request for FWP Approval of Biological Evaluation
• EPA Approval Letter
• US Fish & Wildlife Service Approval Letter
• 303(d) List (CSV format)

• 2004 Integrated Report
• Appendix A - Water Quality Assessment Process and Methods
• Appendix B - Waters to be Monitored & Reassessed - Lacking Sufficient Credible Data
• Appendix C - Waters with Use Support Assessments
• Appendix D - Impairment Cause Changes
• Appendix E - Beneficial Use Designation Changes
• Appendix F - Monitoring & Assessment Schedule
• Appendix G - Planning Area Impaired Waters Scheduled for TMDL Completion through 2006
• Appendix H - EPA Approved TMDLs
• 303(d) List (Excel format)
• 303(d) List (text format)

• 2002 305(b) Water Quality Report
• 2002 303(d) List Overview
• Errata Sheet
• Appendix A - Water Quality Assessment Process and Methods
• Appendix B - Causes Delisted
• Appendix C - Approved TMDLs
• Appendix D - MPDES Permit Renewal Schedule
• Appendix E - TMDL Development Schedule
• Appendix F - Waters Requiring Reassessment
• EPA Approval Letter
• 303(d) List (Excel format)
• 303(d) List (text format)

• 2000 303(d) Part A - Water Quality Assessment Results
• 2000 303(d) Part B - Waterbody Ranking, Priority Lists, and Schedule
• Appendix A - Water Quality Assessment Process and Methods
• Appendix B - Waterbody Reassessment Schedule
• 303(d) List (Excel format)
• 303(d) List (text format)

• Montana Water Quality 1998
• 1998 303(d) List Report

• 1996 303(d) List Report
• 303(d) List (Excel format)
• 303(d) List (text format)

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

All well owners should conduct an annual water well "check-up" that includes a wellhead and pressure tank inspection. Conducting an annual well check-up of your water system is an important step to take to ensure proper operation of a well. A check-up can prolong your system’s years of service as you monitor water quality.

• At a minimum, test your water for coliform bacteria and nitrates. You can also test for any additional contaminants that may be specific for your area. You should also have your water tested if there is a: change in taste, odor, or appearance; after the well system is serviced; or after a flooding event.
• Inspect your well parts to ensure they are in good repair. Look for problems such as cracked, corroded, or damaged well casing or settling and cracking of the ground surface around the well casing. If any of these problems are present, your well can become a conduit for contamination to ground water.
• Check to make sure your well cap is not broken or missing. If your well does not have a sanitary cap (a two-part cap with a rubber seal), it is recommended that you replace it with a sanitary well cap.
• Inspect your pressure tank and associated plumbing by looking for things like leaks or corrosion, which could lead to future problems.
• Survey the area around your well to make sure there are no hazardous materials nearby (paint, motor oil, household chemicals, etc.) which could spill and contaminate your well water.

How do you know your drinking water is safe? It’s simple - test it. Generally, private water supplies should be annually tested for nitrate and bacterial contamination. Otherwise, drinking water should be tested if:

• you notice a change in your water quality;
• people using the water suffer from an illness that may be waterborne;
• there is a flood or large storm that may have carried contaminants to your wellhead;
• maintenance work has been performed on the well;
• a water user is pregnant, anticipating pregnancy, or is an infant under the age of six months

What should you test for?

There is a broad range of potential chemical and biological groundwater contaminants which can find their way into your water supply. Testing for all of them would be extremely expensive. By assessing which contaminants your well is at highest risk from you can determine what to test for.

It is best to perform coliform bacteria tests in the spring during wet weather. This is when bacteria is most likely to be found because runoff and excess soil moisture can carry contaminants into shallow groundwater sources or through well defects. Test for other substances when specific contamination is suspected. This might be the result of a spill or backflow, use of harmful products in close proximity to the well, or other similar events. Any noticeable change in water taste, color, or smell signals the need for testing.

Where can I get my water tested?

Many commercial laboratories in Montana have the facilities to test water. Prices vary but will often be competitive with state labs. When obtaining laboratory services for water testing, look for three things:

• Guidance with collecting samples
• Analytical services available
• Assistance with interpretation of results

The State of Montana requires certified labs to adhere to the State of Montana Drinking Water Certification requirements which have been adapted from the EPA Manual for the Certification of Laboratories Analyzing Drinking Water.

• Certified Montana Drinking Water Testing Labs

How do I go about getting a test done?

After you have thought about what to test your water for, choose a lab from the sources above. Next contact the lab to find out about containers and shipping of samples. Most labs will send you sample bottles and instructions for free. If there is a lab in your area, you may want to transport the sample yourself to ensure timely delivery. Samples need to get to the lab quickly, preferably within 24 hours of collection.

Water Sampling Tips

• Use a clean, indoor faucet
• Try to avoid threaded taps, leaky, or swing-type faucets
• Do not use a dirty or contaminated tap
• Do not sample through a hose or treatment device
• Always sample the cold water
• Allow the water to run in a steady stream at least five minutes before collecting the sample or until the pump runs
• Do not set the bottle cap down
• Do not touch the inside of the cap or bottle
• Do not allow the cap or bottle to touch the faucet
• Do not rinse the bottle
• Maintain a steady low-flow stream
• Fill the container to the fill line. Do not overfill
• Seal the container as soon as it is filled
• Enclose submission slip and proper payment with sample
• Send/transport samples to the lab the same day of collection and early in the week

What do my test results mean?

Water quality tests performed by certified laboratories test according to Safe Drinking Water standards. Visit the links below for information on understanding how your well water test results compare to these standards.

• Understanding Your Test Results
• Water Quality Interpretation Tool

Childcare facilities in Montana may contain naturally occurring or human-made substances such as bacteria, nitrates, lead, arsenic, fluoride, manganese, uranium, and pesticides. Drinking water with these substances can cause unwanted or harmful health effects among children and staff at childcare centers, depending on the levels. Testing is the only way to know if these substances are in your well water.

If your childcare center’s well water has not been tested beyond the basics, we encourage you to test your well water through Montana Department of Public Health and Human Services' free well water testing program. This program is open to all prospective or licensed childcare facilities and fulfills the well water testing licensing requirement. Results are kept confidential. To request a test, fill out the Montana Choose Safe Places Private Well Water Testing Program Request Form.

Because of the extensive damage and soil saturation caused by floods, private or public drinking water wells may not be safe and may be contaminated with bacteria and other contaminants such as sewage and chemicals. If you suspect your well has been affected by flooding, you should have your well disinfected and tested. In addition, wastewater and chemicals from inundated and malfunctioning septic tanks or storage tanks may have seeped into the ground and contaminated the ground water, even after the water has been tested and found to be safe. It will be necessary to take long-range precautions, including repeated testing, to protect the safety of drinking water. See additional flood tips in the links below.

Wells

• What to do After the Flood - Well Inspection & Treatment
• EPA Emergency Disinfection of Drinking Water

Septic Systems

• Manage Your Septic During and Following a Flood

Below is a list of resources to assist homeowners with septic system operations and maintenance.

• Septic System Function
• Private Septic Systems: No Monthly Utility Bill, but...
• Septic Tank Inspection and Trouble-Shooting MontGuide
• Septic Tank and Drainfield Operation and Maintenance MontGuide
• Underground Comics: Septic & Well Care for Clean Water

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.