From limestone to your faucet
The Biscayne Aquifer is porous limestone, and groundwater picks up calcium moving through it. At the northern plants, lime is added to soften the water and the particles settle out as lime sludge before filtering and disinfection. What's left at your tap varies; WASD's report doesn't list a hardness number per home.
Private well water skips that plant step entirely, which is why well homes often see heavier scale than neighbors on county water.
Where it shows up
- Glass shower doors, mirrors and windows hit by sprinklers.
- Faucet aerators and shower heads.
- Dishwasher glassware.
- Water heaters and tankless units.
- Pool tile lines and cars washed with hose water.
Where you see it most, and how quickly, is part of what Jorge asks about during the visit.
Windows near sprinklers
In a town with 23 lakes, many sprinkler systems don't run on county water. Spots on windows near sprinkler heads often come from irrigation water, which can carry more minerals and iron than treated tap water. That's an irrigation fix, not an indoor softener. See orange stains in Miami Lakes.
Test first
Jorge measures hardness and dissolved solids at your tap and asks how fast spots appear. Low hardness means habits will do; higher hardness may justify a softener. Private wells usually test harder than county water.
Pattern matters: spots that appear within hours point to higher hardness than spots that build over weeks.
Softener vs. conditioner
| Ion-exchange softener | Salt-free conditioner | |
|---|---|---|
| Removes hardness | Yes | No, changes its behavior |
| Spots on glass | Reduced | May still appear |
| Needs | Salt, drain | No salt |
After measuring, Jorge walks through both options, and if your hardness is low he'll recommend neither.
Scale inside appliances
Scale builds wherever water is heated: tank and tankless water heaters, coffee makers and dishwashers. If your measured hardness is notable, softening slows how quickly that returns. Either way, follow the appliance maker's descaling and flushing guidance.
Habits that help
- Squeegee glass after showers.
- Soak aerators and shower heads in vinegar now and then.
- Use rinse aid in the dishwasher.
- Flush tankless heaters per the maker's guidance.
Call, text or WhatsApp (305) 793-5974 for a free hardness test.
If spots come back within days despite these habits, that's a sign hardness at your tap is worth measuring and possibly treating.
https://www.miamidade.gov/resources/water/documents/2025-water-quality-report.pdf
https://www.miamilakes-fl.gov/our-community/history/
Updated 2026-10-17 · Living Waters · Jorge Canela, Water Quality Specialist