Boulder, Colorado’s Home for
Water Softeners, Water Filters,
& Water Delivery

Yes. Boulder’s drinking water meets federal and state drinking water standards. The city completes required testing for regulated contaminants, and results are reviewed to confirm compliance with Safe Drinking Water Act requirements.

Boulder’s tap water is considered soft to moderately hard, with an average hardness of approximately 42 mg/L (2.4 grains per gallon). Water in this range typically causes minimal scale buildup, reduces spotting on fixtures, and supports better soap efficiency compared to harder water supplies. These figures apply to homes on City of Boulder water. Homes on private wells in the foothills and mountain areas can have much harder water (see the well water question below).

Recent sampling for Boulder, Colorado drinking water has not detected PFAS compounds above reporting limits. In April 2024 the EPA finalized the first national drinking water limits for PFAS, setting an enforceable maximum of 4 parts per trillion — 0.000000000004 — each for PFOA and PFOS. In May 2026 the EPA proposed extending the compliance deadline for those limits to 2031, and separately proposed rescinding the limits it had set for PFHxS, PFNA and HFPO-DA (GenX), so the rules for those three are currently unsettled. Click here to learn more about our whole house PFAS filtration systems.

Yes. Fluoride is present in Boulder tap water at an average level of approximately 0.69 ppm, which is below the EPA maximum contaminant level of 4.0 ppm. Fluoride enters the water through natural mineral deposits and is closely monitored as part of Boulder’s routine water quality testing program.

Boulder’s drinking water primarily comes from high-quality mountain surface water sources, including Barker Reservoir, North Boulder Creek, Carter Lake, the Boulder Creek watershed, and the Colorado–Big Thompson Project. These mountain-fed supplies provide a reliable source of clean surface water, with seasonal variations based on snowpack and runoff conditions.

Boulder treats its drinking water at two primary treatment facilities using multi-step processes that include coagulation, sedimentation, filtration, and disinfection. Additional treatment is applied to reduce organic material and disinfection byproduct formation, ensuring water meets all safety and quality standards before distribution.

It depends on where your water comes from. Homes on City of Boulder water have relatively soft water, so most homeowners choose filtration for taste, chlorine, sediment, and trace contaminants rather than a softener. Homes on private wells in the foothills and mountain areas often have very hard water and may need a water softener, plus filtration for iron, sulfur, or other minerals depending on test results.

Yes. The Boulder water figures on this page apply only to homes on the City of Boulder system. Many homes in the foothills and mountain communities west of town are outside city service and draw from private wells instead. Groundwater in these areas picks up minerals as it moves through rock, and well water can be much harder than city water. Private wells are also not covered by the city’s testing or its water quality report, so testing is up to the homeowner. If your home is on a well, a free in-home well water test is the best way to see your actual hardness, iron, pH, and other levels before choosing a system.

The City of Boulder operates an extensive source-to-tap water quality monitoring program that includes continuous online instrumentation, laboratory testing, and routine field sampling. Hundreds of samples are collected annually and analyzed in accordance with federal and state regulations.

However, during 2024, Boulder reported several non-health-based monitoring and reporting violations, including:

Although none of these events resulted in unsafe drinking water, they highlight the importance of ongoing oversight, system improvements, and regulatory compliance monitoring.

You can access the most recent Boulder Tap Water Quality Report here.