Drinking Water Quality

The City of Boulder is pleased to present the 2026 Drinking Water Quality Report, which summarizes water quality testing results from 2025. Read the Water Report PDF to learn about the city’s efforts to protect our water supply.

El Gobierno de la ciudad de Boulder se complace en presentar el Reporte de calidad de agua potable de 2026. El reporte resume los resultados de los análisis de la calidad del agua del año calendario 2025. Una copia digital del reporte está disponible en este enlace, que incluye todos los esfuerzos llevados a cabo por la ciudad de Boulder para proteger nuestro abastecimiento de agua.

• 2026 Drinking Water Quality Report PDF (English)
• 2026 Reporte De La Calidad Del Agua Potable PDF (Spanish)

Water quality samples are routinely collected in the water supply creeks and reservoirs, which include the Middle and North Boulder Creek watersheds, as well as Carter Lake and the Colorado-Big Thompson watershed. Water quality is also monitored at the water treatment plants and throughout the city.

• Chlorine Taste and Odor
  The city uses chlorine to disinfect the drinking water. While the city uses the minimum amount necessary to keep drinking water safe, water can have a chlorine taste and odor. Chlorine will dissipate in drinking water if left in an uncovered container in the refrigerator overnight .
• Rusty Water
  Rusty brown/orange water can be caused by a main break, main replacement, construction activities, fire hydrant use, in-home plumbing, or hot water tanks. These activities can disrupt the water distribution system releasing iron from the pipe walls. Flushing the cold water tap should clear the water.
• White or Cloudy Water
  The white water is typically caused by small air bubbles, which will dissipate in a few minutes. If the white water is caused by flakes that don't disappear, this may be caused by a deteriorating dip tube in the property's hot water heater.
• Pink or Black Mildew
  Mildew can form in sinks, showers, toilets or areas with stagnant water. Clean fixtures regularly and fix leaks to reduce mildew and mold growth.
• Water Hardness
  Average water hardness for Boulder’s water is 42 mg/L, equivalent to 2.4 grains/gallon. Water hardness is determined by naturally occurring minerals, including calcium and magnesium.
• PFAS
  In 2023, the city tested for PFAS and found no detections of PFAS compounds in city drinking water. Learn more about PFAS.

• Water Supply and Planning
• Source Water Protection
• Northern Water Monitoring Program