Problems We Found With Denver, Colorado Drinking Water


Analies Dyjak, M.A.  |  Policy Nerd
**Updated May 28, 2021 to include current data 

For our 2021 report of Denver water quality, we collected water quality test data from Denver Water and the U.S. Environmental Protection Agency. We cross reference the city’s water quality data with toxicity studies in scientific and medical literature. The water filters that we sell at Hydroviv are optimized to filter out contaminants that are found in Denver’s drinking water.

Where Does Denver Source Its Drinking Water?

Denver Water is the water utility provider for the city of Denver, which services 1.4 million residents. Denver’s drinking water is fully supplied from surface water sources. The South Platte River and its tributaries, the Dillon Reservoir, and the other tributaries above the Fraser River are the primary drinking water sources. Denver Water stores water is several mountain reservoirs, which are then sent to one of three treatment plants before being distributed into homes.

Lead in Denver’s Drinking Water

Lead enters tap water through old lead service pipes and lead-containing plumbing. 10% of taps test for lead in Denver, had concentrations over 6.7 parts. To make matters worse, houses built before 1986 were most likely built with lead plumbing and lead fixtures. EPA and CDC both recognize that there is no safe level of lead, especially for children.

Chromium 6 in Denver’s Drinking Water

Chromium 6 is a highly toxic metal that is not regulated by the EPA. The city of Denver recently detected levels of Chromium 6 above the California Office of Environmental Health Hazard Assessment public health goal of 20 parts per trillion. The levels of chromium 6 average 37.8 parts per trillion in Denver drinking water. The state of California set their own health advisory level because Chromium 6 is not regulated by the federal government. EPA has acknowledged that Chromium 6 is a known human carcinogen through inhalation, but is still determining its cancer potential through ingestion of drinking water. Lung, nasal and sinus cancers are associated with chromium 6 exposure.

Disinfection Byproducts (DBPs) In Denver’s Drinking Water

Disinfection Byproducts are a category of emerging contaminants which means they have been detected in drinking water, but the risk to human health is unknown. DBPs are formed when chlorine-based disinfectants are routinely added to the water supply to kill bacteria. EPA regulates two different types of DBPs: Total Trihalomethanes (TTHMs) and Haloacetic Acids-5 (HAA5). Regulatory agencies have very little knowledge about the adverse health effects of DBPs, and their toxicity. EPA has however acknowledged their link to an increased risk of bladder cancer, as well as kidney, liver, and central nervous system problems. 

Chloramine in Denver’s Tap Water

Denver's drinking water is disinfected with Chloramine, which is being more broadly used over chlorine in water treatment facilities. Chloramine is primarily responsible for what customers report as the “bad taste” of tap water, and unlike chlorine this taste will not fade if left in the fridge overnight. Most one-size-fits-all water filters use filtration media that doesn’t adequately remove chloramine, but the filters that Hydroviv builds for Denver use special filtration media that is purpose-built to remove chloramine as well.

It’s important to note that only a handful of contaminants are required to be included in annual Consumer Confidence Reports, and that there are hundreds of potentially harmful unregulated contaminants that aren’t accounted for. If you’re interested in learning more about water filters that have been optimized for Denver’s tap water feel free to visit to talk to a Water Nerd on our live chat feature or send us an email at

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