Recycled Water Quality Standards

Recycled water must meet standards set forth in PDF document Regulation 84 (Colorado Department of Public Health and Environment).

The federal government does not currently regulate recycled water quality, and regulations are to be enforced by states. The United States Environmental Protection Agency has published Guidelines for Water Reuse that states may use to establish recycled water quality parameters to be enforced. In Colorado, there are three categories of recycled water, and Denver Water produces Category 3 water, the best recycled water under Regulation 84. Category 3 water is not harmful upon incidental contact, and is safe for irrigating our parks, golf courses and commercial and industrial uses. Furthermore, Denver Water’s recycled water meets federal drinking water standards of the 1980 Safe Drinking Water Act (standards are different today).

Denver Water’s recycled water is disinfected before leaving the treatment plant, and in some locations the water is dechlorinated to protect aquatic life. 

Daily operator checks are performed at the Recycle Plant to ensure water quality. Online analyzers and remote sample stations are used throughout the distribution system to monitor water quality and confirm it is acceptable at customer sites. Additional water quality analyses are conducted at Denver Water’s water quality lab, which is a certified laboratory. Recycled water quality is monitored vigorously by Denver Water and must meet internal standards that are more stringent than CDPHE regulations. 

Denver Water’s recycling plant consistently produces water with turbidity and E. coli levels well within water quality standards set forth in Regulation 84. 

Regulation 84 Water Quality Standards

2015 Reporting Data
Substance & Parameter Limit Average of all samples taken Minimum of all samples taken Maximum of all samples taken
E. coli - MPN/ 100 ml None detected in > 75% of samples <1 MPN/100 ml (less than 1) <1 MPN/100 ml (less than 1) <1 MPN/100 ml (less than 1)
Turbidity - NTU

Not to exceed 3 NTU as a monthly average.

Not to exceed 5 NTU in no more than 5% of samples.

0.09 NTU 0.08 NTU 0.12 NTU
MPN/100 ml - Most Probable Number NTU = Nephalometric Turbidity Units

See our glossary for explanation of terms.

Additional Testing

Denver Water monitors for constituents in addition to those required under Regulation 84 to ensure high water quality. Denver Water's water quality lab regularly conducts additional analysis to provide information that is helpful for plant operation and customer application.

Facts about Lowry Landfill

Although there has been some public concern that the wastewater effluent from the Robert W. Hite Wastewater Treatment Plant might be contaminated with radioactive and other hazardous wastes, these claims have been disproven. These concerns are primarily due to speculation that such contamination might be coming from Lowry Landfill, a Superfund site currently undergoing clean-up under the supervision of the U.S. Environmental Protection Agency (EPA). Learn more about Lowry Landfill.

More Information

Contact Damian Higham at 303-628-6537 or damian.higham@denverwater.org.