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Regulation 85 FAQs

What is Regulation 85?


Regulation 85 is also known as the Nutrients Management Control Regulation. In 2012, Colorado passed Regulation 85, along with Regulation 31, to address nitrogen, phosphorus, and chlorophyll a in the state’s surface water in accordance with the Clean Water Act.


Whom does Regulation 85 regulate?


Regulation 85 specifically regulates “point sources” of nutrient discharge, such as wastewater treatment plants, by setting discharge limits and requiring monitoring to better define nutrient levels.  This information will be used to inform future regulatory decisions.


Does Regulation 85 impact agriculture?


Regulation 85 does not currently regulate “nonpoint sources” of nutrient discharge, which includes most agriculture.  But Regulation 85 does identify agriculture’s role in managing nutrient pollution and encourages voluntary adoption of best management practices.

Future state regulations will depend on agriculture’s ability to voluntarily demonstrate commitment to water quality protection.


Why should agriculture be concerned about Regulation 85?


The management of nonpoint sources, including agriculture, is considered an essential part of water quality protection. If voluntary efforts are determined to be ineffective by the year 2022, more stringent regulations may be adopted.


How can agriculture influence Regulation 85?


Producers can influence what happens next by educating themselves on Regulation 85, implementing effective best management practices, taking part in water quality monitoring projects, and participating in regulation hearings and meetings


Do other states regulate nutrients in water quality?


Yes. Across the United States, agriculture is being cited as a significant source of nutrient pollution in water quality.


Water Quality FAQs

What is the difference between surface water and groundwater?


Surface water is generally considered to be water on the surface of the earth, such as in rivers, streams, lakes, reservoirs, wetlands, and the ocean. Surface water can be contrasted with groundwater, which is subsurface water that saturates underground formations and aquifers. However, the two water systems are interrelated. Regulation 85 regulates Colorado’s surface waters.

What is stormwater?


Stormwater is water that originates from natural precipitation events and from snow/ice melt. Stormwater can be contrasted with applied irrigation water that is humanly controlled and originates from various sources. Both stormwater runoff and irrigation water runoff  have the potential to carry nutrients.

What is a “point source” of discharge or pollution?


A “point source” is a single, identifiable source of discharge such as a pipe, drain, ditch, or confined animal feeding operation (CAFO).

What is a “nonpoint source (NPS)” of discharge or pollution?


Nonpoint source (NPS) discharge is diffuse, or distributed over a wide area, and therefore difficult to pinpoint. Examples include agriculture, urban stormwater runoff, and forestry.

What is nutrient pollution?


Nutrient pollution is a widespread national challenge that is caused by excess nitrogen and phosphorus in the water and air. Nutrients are a natural part of the ecosystem. But a wide range of human activities can cause too much nitrogen and phosphorus to enter the water and air.

What are sources of nutrient pollution?

  • Sewage treatment plants
  • Landscape fertilizer
  • Animal waste
  • Agriculture
  • Urban stormwater runoff
  • Faulty septic systems

Are nitrogen and phosphorus considered toxic?


No. These plant nutrients are a natural part of the ecosystem and are required for plant growth. However, excess levels in water supplies can create environmental and human health problems.

What is chlorophyll a?


Chlorophyll is a green pigment in plants, algae, and some bacteria that allows plants to do the process of photosynthesis. Chlorophyll “a” is the predominant type of chlorophyll found in green plants and algae and a measure of the amount of algae growing in a waterbody.

What are the major negative impacts of nutrient pollution?

  • Algal blooms:
    • fish kills, aquatic dead zones
    • reduced recreational value
    • dangerous toxins and bacteria
  • Drinking water contamination
    • nitrates interfere with oxygen transport in humans
    • increased water treatment costs

What are algae and algal blooms?


Algae refer to simple aquatic organisms, such as seaweed, pond scum, and plankton. Too much nitrogen and phosphorus in the water causes algae to grow faster than a waterbody ecosystem can handle. Large growths of algae are called “algal blooms.” 

What is eutrophication?


Eutrophication is the natural aging process of a lake or pond marked by increasing levels of plant nutrients and the resulting increase in plant and animal life. This process can occur both naturally and artificially. Excessive eutrophication and algae growth disrupts the normal balance of a lake and can choke out animal life.

How do nutrients contaminate drinking water?


Levels of nitrate, one form of nitrogen, are regulated in public drinking water. Nitrate-nitrogen may not exceed 10 ppm. Nitrates can interfere with the ability of human red blood cells to transport oxygen. Infants and persons with compromised health may appear to turn “bluish” and have difficulty breathing.

Nitrate pollution can also drive up water treatment costs. 

What is parts per million or ppm?


A unit of proportion used to describe the concentration of a chemical in water. Parts per million (ppm) is equivalent to milligrams per liter (mg/L).


What are BMPs?


Best management practices, or BMPs, are structures, methods, and practices designed to protect water quality. Some BMPs provide economic benefits, as well as environmental benefits, through increased crop yields and decreased input expenses. Recommended BMPs may include widely accepted and utilized agricultural practices.

How are the nitrogen and phosphorus cycles relevant to agriculture?


Nitrogen and phosphorus each naturally cycle through the environment through chemical and biological transformations into various forms. Crop growth is dependent on the forms of these nutrients that are available for uptake and use by plants. Understanding nutrient cycles can help maximize plant growth and crop yields while minimizing harmful losses to the environment.

What forms of nitrogen are available to plants?


Plants can use nitrogen in two forms:

  1. ammonium-nitrogen (NH4+ – N)
  2. nitrate-nitrogen (NO3 – N)



What is nitrogen mineralization?


The process that converts nitrogen into forms that are available to plants. Microbes decompose organic nitrogen from manure, organic matter and crop residues into ammonium (NH4+). Rates of mineralization vary with soil temperature, moisture, and soil aeration.

What sources provide nitrogen to the soil?

  • Organic matter: crop residue, manure, biosolids, compost
  • Synthetic fertilizers
  • Atmosphere: nitrogen fixation, lightning, nitrogen deposition

What are quick-release nitrogen fertilizers?


Synthetic nitrogen fertilizers containing ammonium, nitrate, or urea are considered to be “quick-release” fertilizers that rapidly become plant available.

What are slow-release and controlled-release nitrogen fertilizers?


These synthetic fertilizers are designed to delay the release of plant available nitrogen.

What is phosphorus mineralization?


The process that converts phosphorus into forms that are available to plants. Microbes break down organic phosphorus and release inorganic phosphates that are available to plants.

What forms of phosphorus are available to plants?


Plants use forms of phosphorus known as orthophosphates:

  • H2PO4
  • HPO42-


What is an “agronomic rate” of nutrient application?


A nutrient application rate based upon current crop needs that takes into account already available residual soil nutrients as well as nutrients from all applied sources, such as commercial fertilizers, manure, and irrigation water.

Why is soil erosion management important to managing nutrients and other water quality issues?


Soil erosion can result in the loss of soil sediments from cropland to surface waterways. Nutrients and other chemicals can be adsorbed onto the surface of eroding soil sediments, carrying pollution into surface waterways.  In addition, soil sediments cause pollution through reduced water clarity that impacts plant and animal life and drives up water treatment costs.  Sediment deposits can also alter waterway flows and depths.    

Soil conservation practices can minimize soil erosion while also improving soil structure to more efficiently use nutrients and water.

What is conservation tillage?


Conservation tillage refers to tillage and planting systems that maintain at least 30% of the soil surface covered by residue following planting, or a system that maintains at least 1,000 pounds per acre of small grain residue on the surface during the critical erosion period.

What are the drawbacks of conventional tillage?


Conventional tillage (or clean tillage) often results in overtilled soils, which causes the loss of organic matter and the breakdown of soil structure. Clean tillage can also promote soil erosion, create soil compaction, increase soil moisture loss, as well as increase labor and production costs.

What are the benefits of conservation tillage?

  • Reduce/eliminate field operations, which reduces production costs and soil compaction
  • Reduces soil erosion caused by wind and water, which maintains crop production sustainability and protects water quality
  • Provides wildlife shelter and habitat

What is irrigation uniformity?


A measure of how evenly irrigation water is applied across a crop area.