Miami water hardness is not one number. It depends on which WASD plant treats your water, and WASD's 2025 report prints no hardness figure for any system. Florida DEP's 2024 sample file does give calcium hardness medians at the main-system plant entry points: 45.3 mg/L at Hialeah, 69 mg/L at Orr, and 81.3 mg/L at Preston. Those are calcium hardness only. Total hardness runs higher. The WASD 2025 report also says the Alexander Orr Jr. plant uses lime treatment to reduce hardness, and the Preston plant uses enhanced softening. For the South Dade system, the DEP's 2024 file shows total hardness medians of 232 to 263 mg/L across its five plants. The WASD 2025 report describes no softening step there.
The utility printed on your bill is the one whose report applies to your address. It does not tell you which plant is feeding your block on any given day. The guide on hard water in Miami explains what those figures mean. If you want to read a utility report yourself, see how to read your utility's annual water report. If you are thinking about a filter or have questions about your home's setup, reach out to us and we will tell you honestly what we can help with.
