Is Denver Tap Water Safe to Drink?

Can You Drink Tap Water in Denver?

Yes, Denver's tap water is generally considered safe to drink as Denver has no active health based violations of the Safe Drinking Water Act (SDWA) that we are aware of. Other factors such as lead piping in a home, or low levels of pollutants on immunocompromised individuals, should also be considered, however. To find more recent info we might have, you can check out our boil water notice page, the city's water provider website, or Denver's local Twitter account.

According the EPA’s ECHO database, from April 30, 2019 to June 30, 2022, Denver's water utility, Denver Water Board, had 1 non-health-based violations of the Safe Drinking Water Act. For more details on the violations, please see our violation history section below. The last violation for Denver was resolved on May 31, 2019. This assessment is based on the Denver Water Board water system, other water systems in the city may have different results.

While tap water that meets the EPA health guidelines generally won’t make you sick to your stomach, it can still contain regulated and unregulated contaminants present in trace amounts that could potentially cause health issues over the long-run. These trace contaminants may also impact immunocompromised and vulnerable individuals.

The EPA is reviewing if it’s current regulations around pollutant levels in tap water are strict enough, and the health dangers posed by unregulated pollutants, like PFAS.

Water Quality Report for Denver Tap Water

The most recent publicly available numbers for measured contaminant levels in Denver tap water are in its 2020 Water Quality Report. As you can see, there are levels which the EPA considers to be acceptable, but being below the maximum allowable level doesn’t necessarily mean the water is healthy.

Lead in tap water, for example, is currently allowed at up to 15ppb by the EPA, but it has set the ideal goal for lead at zero. This highlights how meeting EPA standards doesn’t necessarily mean local tap water is healthy.

EPA regulations continue to change as it evaluates the long term impacts of chemicals and updates drinking water acceptable levels. The rules around arsenic, as well as, lead and copper are currently being re-evaluated.

There are also a number of "emerging" contaminants that are not currently. For example, PFAS (Per- and polyfluoroalkyl substances), for which the EPA has issued a health advisory. PFAS are called "forever chemicals" since they tend not to break down in the environment or the human body and can accumulate over time.

We recommend looking at the contaminants present in Denver's water quality reports, or getting your home's tap water tested to see if you should be filtering your water.

Denver Tap Water Safe Drinking Water Act Violation History - Prior 10 Years

Below is a ten year history of violations for the water system named Denver Water Board for Denver in Colorado. For more details please see the "What do these Violations Mean?" section below.

From May 1, 2019 to May 31, 2019, Denver had 1 non-health based Safe Drinking Water Act violation with the violation category being Monitoring and Reporting, more specifically, the violation code was Monitoring, Turbidity (Enhanced SWTR) which falls into the Microbials rule code group, and the Surface Water Treatment Rules rule code family for the following contaminant code: Interim Enhanced Surface Water Treatment Rule.

From Jan. 1, 2014 to Dec. 31, 2016, Denver had 93 non-health based Safe Drinking Water Act violations with the violation category being Monitoring and Reporting, more specifically, the violation code was Monitoring, Regular which falls into the Chemicals rule code group, and the Synthetic Organic Chemicals rule code family for the following contaminant codes: Endrin, BHC-GAMMA, Methoxychlor, Endothall, Di(2-ethylhexyl) adipate, OXAMYL, Simazine, Di(2-ethylhexyl) phthalate, Hexachlorocyclopentadiene, Aldicarb sulfoxide, Aldicarb sulfone, Carbofuran, Atrazine, Heptachlor, HEXACHLOROBENZENE, Pentachlorophenol, Total Polychlorinated Biphenyls (PCB), ETHYLENE DIBROMIDE, Chlordane, BHC-GAMMA, Methoxychlor, Toxaphene, Dalapon, Endothall, Di(2-ethylhexyl) adipate, OXAMYL, Simazine, Di(2-ethylhexyl) phthalate, Picloram, Hexachlorocyclopentadiene, Carbofuran, Aldicarb, Atrazine, Heptachlor, Heptachlor epoxide, 2,4-D, HEXACHLOROBENZENE, Pentachlorophenol, 1,2-DIBROMO-3-CHLOROPROPANE, ETHYLENE DIBROMIDE, Endrin, Dalapon, Diquat, Endothall, Di(2-ethylhexyl) adipate, Simazine, Di(2-ethylhexyl) phthalate, Dinoseb, Aldicarb sulfoxide, Aldicarb sulfone, Carbofuran, Aldicarb, Atrazine, LASSO, Heptachlor, Heptachlor epoxide, 2,4-D, 2,4,5-TP, Pentachlorophenol, 1,2-DIBROMO-3-CHLOROPROPANE, ETHYLENE DIBROMIDE, Chlordane, Dinoseb, 2,4,5-TP, Hexachlorocyclopentadiene, LASSO, Heptachlor epoxide, OXAMYL, Toxaphene, LASSO, 1,2-DIBROMO-3-CHLOROPROPANE, Toxaphene, Benzo(a)pyrene, Endrin, Chlordane, Dalapon, Picloram, 2,4,5-TP, Total Polychlorinated Biphenyls (PCB), Diquat, Picloram, Total Polychlorinated Biphenyls (PCB), BHC-GAMMA, Dinoseb, Aldicarb, Methoxychlor, Benzo(a)pyrene, 2,4-D, Aldicarb sulfoxide, Diquat, Aldicarb sulfone, Benzo(a)pyrene, HEXACHLOROBENZENE.

Is there Lead in Denver Water?

Based on the EPA’s ECHO Database, 90% of the samples taken from the Denver water system, Denver Water Board, between sample start date and sample end date, were at or below, 0.0045 mg/L of lead in Denver water. This is 30.0% of the 0.015 mg/L action level. This means 10% of the samples taken from Denver contained more lead.

While Denver water testing may have found 0.0045 mg/L of lead in its water, that does not mean your water source has the same amount. The amount of lead in water in a city can vary greatly from neighborhood to neighborhood, or even building to building. Many buildings, particularly older ones, have lead pipes or service lines which can be a source of contamination. To find out if your home has lead, we recommend getting you water tested.

No amount of lead in water is healthy, only less dangerous. As lead accumulates in our bodies over time, even exposure to relatively small amounts can have negative health effects. For more information, please check out our Lead FAQ page.

Are there PFAS in Denver Tap Water?

Currently, testing tap water for PFAS isn’t mandated on a national level. We do have a list of military bases where there have been suspected or confirmed leaks. There appears to be at least one military base - Lowry Air Force Base - near Denver with suspected leaks.

With many potential sources of PFAS in tap water across the US, the best information we currently have about which cities have PFAS in their water is this ewg map, which you can check to see if Denver has been evaluated for yet.

Our stance is better safe than sorry, and that it makes sense to try to purify the tap water just in case.

Denver SDWA Violation History Table - Prior 10 Years

What do these Violations Mean?

Safe Drinking Water Act Violations categories split into two groups, health based, and non-health based. Generally, health based violations are more serious, though non-health based violations can also be cause for concern.

Health Based Violations

1. Maximum contaminant levels (MCLs) - maximum allowed contaminant level was exceeded.
2. Maximum residual disinfectant levels (MRDLs) - maximum allowed disinfectant level was exceeded.
3. Other violations (Other) - the exact required process to reduce the amounts of contaminants in drinking water was not followed.

Non-Health Based Violations

1. Monitoring and reporting violations (MR, MON) - failure to conduct the required regular monitoring of drinking water quality, and/or to submit monitoring results on time.
2. Public notice violations (Other) - failure to immediately alert consumers if there is a serious problem with their drinking water that may pose a risk to public health.
3. Other violations (Other) - miscellaneous violations, such as failure to issue annual consumer confidence reports or maintain required records.

SDWA Table Key

For more clarification please visit the EPA's data dictionary.