How hard is the water in Tempe?

Tempe water hardness ranges from 12.3-13.9 GPG (210-238 PPM), classified as "Hard" to "Very Hard." The hardness is relatively consistent across the city compared to some neighboring communities.

Why does Tempe water sometimes taste earthy?

Tempe's water is heavily influenced by the Salt River, which can develop algae blooms that release Geosmin—a compound that causes an earthy or musty taste. The city uses carbon filtration to address this, but the taste can be noticeable during peak bloom periods, typically in fall.

Where does Tempe get its water?

Tempe receives water primarily from the Salt and Verde Rivers via the Salt River Project. The Salt River tends to have higher TDS and chlorides, while Verde River water has higher carbonate hardness. The blend depends on reservoir levels and demand.

Is Tempe water safe to drink?

Yes, Tempe water is safe to drink and meets all EPA and state safety standards. The Municipal Utilities department regularly tests and treats the water supply. The earthy taste from Geosmin is harmless, just unpleasant.

Do ASU students need water filters?

While Tempe water is safe, many residents (including students) prefer filtered water for taste. A simple carbon filter pitcher will remove chlorine taste and the occasional earthy notes. For hard water issues like scale, a water softener is needed.

Tempe Water Quality: What Students and Residents Should Know

What This Means For You

At 13 grains per gallon (GPG), Tempe has hard water that falls in the middle range for the Phoenix metro area. Home to Arizona State University, Tempe serves a diverse population of long-term residents and students.

Tempe's water is heavily influenced by the Salt River, which is characteristically higher in Total Dissolved Solids (TDS) and chlorides compared to the Verde River. The city uses substantial carbon filtration to address the "earthy" taste (Geosmin) common with surface water supplies. Home to Arizona State University, Tempe has significant water demand.

While hard water is safe to drink, it can cause scale buildup in pipes and appliances, spots on dishes, and dry skin and hair. The occasional earthy taste from Geosmin is harmless but noticeable to sensitive palates.

Water Hardness in Tempe, Arizona

What This Means For You

Frequently Asked Questions

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