Question 1

Where does Denver's drinking water come from?

Accepted Answer

Denver Water sources approximately 75% of its supply from the mountains west of the Continental Divide (Dillon Reservoir, Williams Fork Reservoir, and others). The remaining 25% comes from the South Platte River basin east of the Divide. The water travels through a system of tunnels, pipelines, and treatment facilities before reaching your tap.

Question 2

How does Denver Water treat the water?

Accepted Answer

Denver Water uses a multi-step process: coagulation (adding chemicals to clump particles), flocculation and sedimentation (settling particles), filtration (sand and activated carbon), and disinfection with chloramines (a combination of chlorine and ammonia that provides longer-lasting protection than chlorine alone). They do NOT treat for hardness.

Question 3

Why does Denver Water use chloramines instead of chlorine?

Accepted Answer

Chloramines dissipate more slowly than free chlorine, so they remain effective longer in the distribution system (Denver has an extensive pipe network). They also produce fewer disinfection byproducts (DBPs) than chlorine, which is a regulatory concern. The tradeoff is that chloramines are harder to remove than chlorine — they require a catalytic carbon filter, not just a standard carbon filter.

Question 4

Is Denver Water hard or soft?

Accepted Answer

Denver's municipal water is classified as hard water, averaging 7.8 GPG (133 mg/L). Water hardness in the Denver system varies by location and season, ranging from about 6.5 to 9.5 GPG depending on your specific neighborhood and the time of year.

Question 5

Does Denver Water add fluoride to the water?

Accepted Answer

Yes. Denver Water adds fluoride to maintain a level of 0.7 mg/L, which is the level recommended by the U.S. Public Health Service for dental health. This is consistent with state and federal guidelines.

Question 6

How can I get my Denver water tested?

Accepted Answer

Denver Water offers free lead testing for customers with concerns about their service line. For comprehensive water quality testing (hardness, TDS, contaminants), contact a state-certified laboratory. CSU Extension and commercial labs like National Testing Labs and Tap Score offer mail-in testing starting around $50.

Question 7

Does Denver Water have any known water quality issues?

Accepted Answer

Denver Water consistently meets or exceeds all EPA and state water quality standards. Lead levels have been well below the 15 ppb action level. No significant PFAS contamination has been detected. The water is safe by all regulatory measures.

Question 8

Why does my Denver tap water sometimes smell like chlorine?

Accepted Answer

Denver Water uses chloramines, which have a slightly different smell than free chlorine — sometimes described as a "pool-like" smell. If the smell is stronger than usual, it may be because water from a different treatment plant is flowing through your area, or there was recent main flushing. The smell indicates the disinfectant is doing its job; an activated carbon filter removes it easily.

Question 9

What is Denver Water's pH?

Accepted Answer

Denver Water adjusts pH to between 7.8 and 8.2 (slightly alkaline) to minimize corrosion of pipes and plumbing fixtures. This is also within the EPA's recommended range for drinking water.

Question 10

How do I read my Denver Water bill?

Accepted Answer

Denver Water bills in hundred cubic feet (CCF). 1 CCF = 748 gallons. Rates are tiered: the first block (0-6 CCF) is lower, higher usage costs more per CCF. Average Denver household uses 3-5 CCF per month. A water softener's regeneration cycles add water use but typically less than 0.2 CCF per month.

Denver Water FAQ