Miami-Dade Water and Sewer Department publishes a water quality report each year. The 2025 report covers monitoring from January 1 through December 31, 2025. Service boundaries vary across the county, and not every address is served by WASD. Your water bill tells you which utility serves you. Our guide on does Miami have hard water has more on what the report does and does not say.
According to the 2025 WASD report, the main system draws groundwater primarily from the Biscayne Aquifer, a shallow porous-rock formation beneath South Florida that rainwater seeps into and fills. The Alexander Orr Jr. plant uses lime treatment to reduce hardness before disinfection and filtration. The Hialeah Water Treatment Plant also uses lime softening, disinfection, and filtration, and adds air stripping to remove volatile organic compounds. The Hialeah Reverse Osmosis Water Treatment Plant is a separate plant that draws from the Upper Floridan Aquifer at roughly 1,400 feet deep and uses reverse osmosis before pH adjustment and chlorine disinfection. The 2025 report prints no hardness figure for any part of the system; if you want a number, the utility is the right place to ask. If you want help reading the full report, our page on how to read your utility's annual water report walks through what the columns mean.