Water Quality Standards
The DNR manages water quality through the implementation of the state's Water Quality Standards. These standards are found in Chapter 61 of the Iowa Administrative Code. The States Water Quality Standards help ensure that all Iowans have surface waters that are fishable and swimmable to the fullest extent practicable and water resources that are put to their best beneficial uses.

Site-Specific Water Quality Criteria

Clean Water Act rules allow for site-specific water quality criteria approved by the EPA. Site-specific water quality criteria are established when localized water quality parameters are used to derive criteria in accordance with Iowa’s water quality standards (567 Iowa Administrative Code Chapter 61). For example, the copper biotic ligand model (BLM) may be used to establish site-specific copper criteria as described in the rule-referenced Implementation Procedure for Copper BLM.

Site-specific water quality criteria implemented in Iowa are shown below.

Copper Criteria

Waterbody Upstream latitude
(degrees)
Upstream longitude
(degrees)
Downstream latitude
(degrees)
Downstream longitude
(degrees)
Acute copper criterion (µg/L) Chronic copper criterion (µg/L)

Floyd River

43.1824

-95.8676

43.0684

-95.9153

55.8

33.4

Chapter 61 Rule Making: Aquatic Life Water Quality Criteria for Metals

The Environmental Protection Commission (EPC) has amended Chapter 61 to update aquatic life water quality criteria for selected metals. The final rule will be effective November 11, 2020. Public comments were addressed in a public participation responsiveness summary.

View the Chapter 61 Amendments

Questions regarding the new water quality criteria can be directed to Katie Greenstein at 515-490-2095 or katie.greenstein@dnr.iowa.gov.

Under the Clean Water Act, a state shall from time-to-time hold public meetings for the purpose of reviewing applicable water quality standards and, as appropriate, modifying and adopting standards. See Chapter 61: Water Quality Standards. This review includes, but is not necessarily limited to: designated uses, criteria, and antidegradation.

DNR Contact: Roger Bruner, 515-310-0247, roger.bruner@dnr.iowa.gov

>