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Drinking Water Quality


Boulder implements a comprehensive source to tap water quality monitoring program. 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.












Water Quality Results

All drinking water, including bottled water, contains substances that do not necessarily pose health risks. The city goes above and beyond regulatory requirements, monitoring for 450+ water quality substances including basic chemistry, nutrients, bacteria, metals, disinfection byproducts, pesticides, pharmaceuticals, personal care products, hormones, and radionuclides. The vast majority of these compounds and chemicals are not detected in drinking water.

Annual Drinking Water Quality Reports

Common Customer Questions

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. For information on current water repair projects click here . 

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.