Where the minerals come from
The Biscayne Aquifer is porous limestone. Rainwater soaks through it and dissolves calcium carbonate along the way. The Miami-Dade Water and Sewer Department (WASD) pumps that water and treats it at regional plants; for most of Coral Gables, south of SW 8 Street, that is the Alexander Orr, Jr. plant, which uses lime treatment to reduce hardness.
Lime softening lowers hardness but does not remove every mineral. What is left shows up where water dries: glass, chrome, tile grout and the inside of kettles.
Where you see it in a Gables home
- Frameless glass shower doors common in renovated bathrooms
- Polished or dark fixtures, where white residue stands out
- Showerheads and aerators that lose flow as scale builds
- Dishwasher glassware with a cloudy film
- Water heaters, where scale builds inside the tank
Outdoors, white crust is usually hardness; orange stains are iron from irrigation wells, a different problem covered on iron stains in Coral Gables.
Testing first
Cleaning-product residue and soap scum can look like hard water. A hardness reading at your tap settles it. Jorge also checks dissolved solids and pH during the free in-home test.
Softener vs. conditioner
| Ion-exchange softener | Salt-free conditioner | |
|---|---|---|
| Removes hardness minerals | Yes | No; aims to change how scale forms |
| Spots on glass | Greatly reduced | Results vary; spots may still appear as water dries |
| Salt and drain | Needs both | Usually neither |
Living Water installs ion-exchange softeners. Read salt-free conditioner vs. ion-exchange softener. If your home is on septic, as about half of Gables properties are according to the city, plan the softener's drain route with the installer.
Scale and your appliances
Spots are the visible part. The same minerals settle inside water heaters, coffee makers, dishwashers and ice makers, where you do not see them until performance drops. Tankless water heaters, common in renovations, often have manufacturer guidance on descaling. If your appliances need frequent descaling or your showerheads clog every few months, that is a useful clue to share with Jorge during the test, because it helps size a softener to your real use.
Low-cost habits that help
- Squeegee glass after each shower
- Soak aerators and showerheads in white vinegar periodically
- Use a rinse aid in the dishwasher
If you are still fighting spots weekly, a softener may be worth a look. Call, text or WhatsApp Jorge at (305) 793-5974.
https://www.miamidade.gov/resources/water/documents/2025-water-quality-report.pdf
https://www.miamidade.gov/global/water/water-supply-and-treatment.page
https://www.coralgables.com/septic-sewer-conversion-program
Updated 2026-10-17 · Living Waters · Jorge Canela, Water Quality Specialist