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Reg 85 Permittees


Under the Clean Water Act, states and authorized tribes are responsible for establishing water quality standards that specify appropriate designated uses, establish criteria to protect those uses, and provide for the protection of downstream waters. Nutrient regulation has been discussed at the national and state level for many years, but the problem is more difficult to define and solve than most of the previous water quality standards. Unlike most other regulated compounds, neither nitrogen nor phosphorus is toxic in the aquatic environment and presence of these compounds in limited amounts is necessary to sustain ecosystems. In addition, the treatment of nitrogen and phosphorus is extremely expensive at point source locations and very difficult to control at non-point source locations. The passage of Regulations 31 (Reg. 31) and 85 (Reg. 85) is Colorado’s solution to nitrogen and phosphorus regulation. The two regulations were passed simultaneously in March of 2012 to both establish scientifically based nutrient regulations and allow point source dischargers time to develop plans to begin treating both nitrogen and phosphorus. Reg. 31 is the Water Quality Control Commission document that establishes statewide water quality regulations for surface waters. Reg. 85 establishes requirements for organizations holding a NPDES permit and with the potential to discharge either nitrogen or phosphorus to begin planning for nutrient treatment based on treatment technology and monitoring both effluents and streams for nitrogen and phosphorus. The data from these efforts is designed to better characterize nutrient sources, characterize nutrient conditions and effects around the state and to help inform future regulatory decisions regarding nutrients.


Nutrient pollution resulting from excess nitrogen (N) and phosporus (P) is a leading cause of degradation of U.S. water quality. Nitrogen and phosphorus together support the growth of algae and aquatic plants, which provide food and habitat for fish, shellfish and other organisms that live in water. Excess N and P in aquatic systems can stimulate production of plant and microbial biomass, which leads to depletion of dissolved oxygen, reduced transparency and changes in biotic community composition. This effect is called eutrophication. In estuaries and coastal waters, nitrogen and phosphorus loading can cause hypoxic zones which are areas of extremely low dissolved oxygen. Hypoxic zones can have severe impacts on fisheries in areas such as the Gulf of Mexico. Nitrogen and phosphorus can come from many sources including: • Fertilizers from agriculture, golf courses and residential lawns • Erosion of soil full of nutrients • Discharges from point sources such as domestic wastewater treatment plants • Deposition of atmospheric nitrogen (nitrogen only) Eutrophication became a more serious problem following the industrial revolution when the first inorganic fertilizers were created. A few major scientific discoveries in plant growth indicated that additions of nitrogen, phosphorus and potassium could promote plant growth. Many of these fertilizers are made to dissolve quickly in water which can stimulate plant growth in gardens and farmer’s fields, but can also promote eutrophication in our nation’s waterways. Excess nitrogen can also cause degradation of aesthetics of recreational waters by turning the water green, often with layers of floating green scum. Health can also be affected when excess nitrogen appears in drinking water wells. Levels above 10 mg/L of nitrate can cause Blue Baby Syndrome which can prevent babies and small children from being able to uptake and process sufficient amounts of oxygen.

Reg. 85 Requirements

The CWQMC, in partnership with the Colorado Monitoring Framework (CMF) and the Water Quality Control Division (Division or WQCD), developed monitoring plans that meet the requirements of Reg. 85. The WQCD has posted several helpful documents regarding Nutrient Monitoring Implementation:

Link: WQCD Website for Nutrients

Documents available include the text of Reg. 85, the required monitoring panels, the SAP certification letter, a flow chart to help you figure out what is required, a PQL table and Q and A’s for both cooling tower and other monitoring programs. If you are just starting this process, check out the flow chart on WQCD's webpage to see what you are required to monitor:

If you are required to monitor, you were required to submit a certification letter by March 1st, 2013 indicating that you have an Sampling and Analysis Plan (SAP) in place to sample effectively for nutrients. The Nutrient Monitoring Framework and the CWQMC have worked together to provide the following sample SAP that can be adapted for your use. Reading through the SAP may give you answers to many of your questions.

Document: Reg 85 SAP Template

DISCLAIMER: The Sampling and Analysis Plan (SAP) was developed during the organization of the Colorado Monitoring Framework (CMF) with funding from the South Platte Coalition for Urban River Evaluation (SP CURE) to provide regulated entities with an example plan to help meet the monitoring requirements of Regulation No. 85 (5 CCR 1002-85). Each entity subject to these monitoring requirements must submit a certification statement to the Water Quality Control Division as set forth in Section 85.6.(4)(d). This example SAP will need to be modified to meet the specific requirements of each individual facility. CMF and SP CURE do not assume any legal liability or responsibility for the accuracy, completeness, or usefulness of the information contained in this example SAP. If you have additional questions, you can sign up for one of our upcoming webinars. Before the webinars, the link will take you to an email so you can sign up for more information. After the webinars have been conducted, a recorded copy will be linked below.

Webinar: Navigating Reg. 85: What, where, and how often to sample…

A Prezi Presentation was developed.

Webinar: Reg. 85: Methods and Data Submission

You can download slides here. A recording of the webinar is available by clicking on the heading above. Navigating Reg 85 Part II Powerpoint Slides

Monitoring Recommendations

Although monitoring is only required at a few locations a few times throughout the year, both the CWQMC and the Colorado Monitoring Framework recommend establishing a comprehensive sampling plan that includes a variety of compounds. DO, pH, and chlorophyll A have all been related to nutrient concentrations, but can also be affected by things like temperature and turbidity. Having a comprehensive picture of water quality that is both spatially and temporally diverse may allow for comprehensive models to be developed to expertly discuss and solve water quality problems on a site-specific basis. If you need additional information on developing a comprehensive monitoring program, please see our Monitoring Page).

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