Reg 85 Monitoring Information


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 (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 Colorado Monitoring Framework, in partnership with the Colorado Water Quality Monitoring Council (CWQMC) and the Water Quality Control Division (Division or WQCD), is attempting to provide additional information to facilitate the development and implementation of monitoring plans that meet the requirements of Reg. 85.

The WQCD has posted several helpful documents regarding Nutrient Monitoring Implementation:

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 required to monitor, you were required to submit a certification letter by March 1st, 2013 indicating that you had a Sampling and Analysis Plan (SAP) in place to sample effectively for nutrients. The Nutrient Monitoring Framework and the CWQMC 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.

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 was required to submit a certification statement to the Water Quality Control Division as set forth in Section 85.6.(4)(d) no later than March 1, 2013. This example SAP was 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, please view one of the of following webinars.

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.

Nutrient Resources

Webinar: Reg 85 Samping – How much and How Often? (January 2013) You can watch the Prezi Presentation here:

Webinar: Reg 85 Methods and Data Submission (February 2013) You can download slides here. Navigating Reg 85 Part II Powerpoint Slides

Links from January 2013 Presentation:

Colorado Division of Water Resources Website

USGS Water Watch

EPA Method 1669

USGS 2007-3099

EPA Volunteer Stream Monitoring Guide

USGS National Field Manual for the Collection of Water Quality Data

State of Maryland, Biological Stream Survey Sampling Manual


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