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

Yes. Centennial’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.

Yes. Centennial’s tap water is hard. The Arapahoe County Water and Wastewater Authority (ACWWA), which supplies the area, reports that its water generally has about 14.5 grains per gallon of hardness — roughly 250 ppm as calcium carbonate — and describes this as very hard water. Water in this hardness range can contribute to scale buildup on fixtures, appliances, and plumbing, reduce soap efficiency, and leave residue on glassware and surfaces.

Recent sampling for Centennial, Colorado drinking water detected the presence of PFAS chemicals. 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 Centennial tap water at an average level of approximately 1.0 ppm, which is below the EPA maximum contaminant level of 4.0 ppm. Fluoride enters the water through natural erosion of mineral deposits and is monitored regularly as part of routine water quality testing.

Centennial’s drinking water is supplied by a combination of groundwater and regional water sources, including shallow and deep aquifers in the Denver Basin, along with water treated at the Joint Water Purification Plant (JWPP) through partnerships with neighboring water districts. Source water originates from groundwater wells, alluvial aquifers near Cherry Creek, and imported supplies, providing a diversified and resilient supply system for the region.

Centennial’s drinking water is treated using multi-step treatment processes that include coagulation, sedimentation, filtration, and disinfection. Treatment is performed through regional purification facilities, including the Joint Water Purification Plant (JWPP), which provides advanced treatment designed to remove sediment, organic material, pathogens, and chemical contaminants before water is disinfected and distributed to homes and businesses.

Many Centennial homeowners choose water treatment systems because ACWWA reports water hardness of about 14.5 grains per gallon (roughly 250 ppm as calcium carbonate), which it describes as very hard. Hardness at that level can contribute to scale buildup in plumbing, appliances, and fixtures. Additional filtration is also commonly used to address taste, odor, sediment, and trace contaminants, including disinfection byproducts and emerging contaminants such as PFAS.

Centennial’s water providers operate an extensive monitoring program that includes routine sampling throughout the distribution system, covering disinfectants, metals, inorganic contaminants, radionuclides, organic compounds, and unregulated contaminants. Hundreds of samples are collected annually and analyzed at state-certified laboratories, ensuring compliance with the Safe Drinking Water Act and early detection of potential water quality issues.

You can access the most recent Centennial’s Tap Water Quality Report here.