Prev Next


(1) The board adopts and incorporates by reference the following state and federal requirements and procedures as part of Montana's surface water quality standards:

(a) Department Circular DEQ-7, entitled "Montana Numeric Water Quality Standards" (June 2019 edition), which establishes numeric water quality standards for toxic, carcinogenic, bioconcentrating, radioactive, and harmful parameters and also establishes human health-based water quality standards for the following specific nutrients with toxic effects:

(i) nitrate;

(ii) nitrate + nitrite; and

(iii) nitrite;

(b) the Water Quality Standards Handbook, Second Edition, EPA-823-B-94-005a, August 1994, that sets forth procedures for development of site-specific criteria;

(c) 40 CFR Part 136 (July 1, 2015), which establishes guidelines and procedures for the analysis of pollutants;

(d) 40 CFR 131.10(g), (h) and (j) (2000), which establishes criteria and guidelines for conducting a use attainability analysis;

(e) Department Circular DEQ-12A, entitled "Montana Base Numeric Nutrient Standards" (July 2014 edition), which establishes numeric water quality standards for total nitrogen and total phosphorus in surface waters; and

(f) the provision in ARM 17.30.1350(1) that authorizes compliance schedules contained in the Montana Pollutant Discharge Elimination System Permit regulations.

(2) If a court of competent jurisdiction declares 75-5-313, MCA, or any portion of that statute invalid, or if the United States Environmental Protection Agency disapproves 75-5-313, MCA, or any portion of that statute, under 30 CFR 131.21, or if rules adopted pursuant to 75-5-313(6) or (7), MCA, expire and general variances are not available, then (1)(e) and all references to DEQ-12A, base numeric nutrient standards and nutrient standards variances in ARM 17.30.201, 17.30.507, 17.30.516, 17.30.602, 17.30.622 through 17.30.629, 17.30.635, 17.30.702, and 17.30.715 are void, and the narrative water quality standards contained in ARM 17.30.637 are the standards for total nitrogen and total phosphorus in surface water, except for the Clark Fork River, for which the standards are the numeric standards in ARM 17.30.631.

(3) Copies of the materials listed in (1) may be obtained from the Department of Environmental Quality, P.O. Box 200901, Helena, MT 59620-0901.


History: 75-5-201, 75-5-301, MCA; IMP, 75-5-301, 75-5-313, MCA; NEW, 2002 MAR p. 387, Eff. 2/15/02; AMD, 2002 MAR p. 2196, Eff. 8/16/02; AMD, 2003 MAR p. 217, Eff. 2/14/03; AMD, 2004 MAR p. 725, Eff. 4/9/04; AMD, 2006 MAR p. 528, Eff. 2/24/06; AMD, 2008 MAR p. 946, Eff. 5/9/08; AMD, 2010 MAR p. 1796, Eff. 8/13/10; AMD, 2012 MAR p. 2060, Eff. 10/12/12; AMD, 2014 MAR p. 1815, Eff. 8/8/14; AMD, 2017 MAR p. 602, Eff. 5/13/17; AMD, 2019 MAR p. 826, Eff. 6/22/19.

Home  |   Search  |   About Us  |   Contact Us  |   Help  |   Disclaimer  |   Privacy & Security