Typical values from 173 sampled wells in Miami-Dade County · Full groundwater profile
Miami-Dade County Well Water at a Glance
Hard water with iron: 15.3 gpg and 0.47 ppm. The typical Miami-Dade well carries both scale-forming hardness and enough iron (above 0.3 ppm) to stain fixtures.
Drink it untreated? Test for arsenic first; it is the main risk here.
What usually fixes it:
- A whole-house sediment filter first, so sand and scale do not foul the stages after it.
- A dedicated iron filter for the 0.47 ppm iron, ahead of any softener.
- A 40,000-grain water softener for a family of four at 15.3 gpg (includes 5 gpg per ppm of iron).
See how a well water filtration system is laid out. Your own test result decides the final list.
Not sure what to install? Get a filter recommendation for Miami-Dade County homesNot on a well? Tap water from a utility is covered by its yearly water quality report (CCR), not by these well samples. Find your utility's report
On this page (7 sections)
Getting Your Well Tested in Miami-Dade County
- Environmental Public Health – Florida Department of Health in Miami-Dade County: 305-623-3500. How the office handles well samples
- Certified labs: how to find a state-certified lab (FDOH)
Contacts as listed on the official page, checked November 2026. Call before you go; hours and fees change.
What Are You Noticing in Your Water?
Pre-selected from Miami-Dade County well data. Untick anything you do not notice in your own water.
Confirm with a lab test before buying equipment.
Explore Florida Interactive Map
Explore Miami-Dade County and nearby counties
Nearly all homes in Miami-Dade County, in Southeast Florida, are on public water. The Florida Department of Health's 2018 inventory counts 0.4% of built parcels, roughly 2,066 properties, on private wells, mostly on rural lots outside utility service areas.
Most groundwater pumped in Miami-Dade County comes from the Biscayne Aquifer (USGS, 2015 withdrawals). Samples from 173 local wells put the median hardness at 15.3 gpg (very hard) and median iron at 0.47 mg/L. The county's largest communities are Miami, Hialeah and Miami Gardens.
In this guide
Groundwater Profile: Miami-Dade County
Across 173 sampled wells, the median hardness is 15.3 gpg (very hard). At 15.3 gpg, Miami-Dade wells run softer than Collier (18.7 gpg) and about as hard as Broward (16.4 gpg) next door.
Another address? Check hardness by ZIP code.
What shows up in local well samples:
- HardnessMedian 15.3 gpg; 99% of 173 sampled wells above 7 gpg
Calcium and magnesium dissolved from limestone. Leaves scale on fixtures and water heaters and reduces soap lather. Not a health risk.
Water softener sizing - IronMedian 0.47 mg/L; 61% of 157 sampled wells above 0.3 mg/L
Stains sinks, toilets and laundry orange-brown and can taste metallic. The EPA aesthetic guideline is 0.3 mg/L. See how to choose an iron filter for your test result.
Iron filter sizing guide - Chloride (salinity)Median chloride 54 mg/L
A salty taste and faster corrosion, often a sign of saltwater intrusion. The EPA aesthetic guideline is 250 mg/L.
Reverse osmosis guide
Hydrogen sulfide was above 0.1 mg/L in 8% of 51 wells tested in Miami-Dade County, so a rotten-egg smell is possible but not typical.
How Miami-Dade County Compares to Florida and the U.S.
See How Miami-Dade County Compares to Florida & the US
| Share of wells with… | Miami-Dade CountyMiami-Dade | FloridaFL | United StatesUS |
|---|---|---|---|
| Hard water (above 7 gpg) | 99% | 79% | 60% |
| Iron above 0.3 mg/L | 61% | 35% | 19% |
| Manganese above 0.05 mg/L | 7% | 8% | 21% |
| Dissolved solids above 500 mg/L | 31% | 22% | 15% |
| Acidic water (pH below 6.5) | <1% | 15% | 14% |
| Nitrate above 10 mg/L (EPA limit) | 0% | 2% | 4% |
| Arsenic above 10 µg/L (EPA limit) | 7% | 3% | 7% |
| Median hardness | 15.3 gpg | 12.4 gpg | — |
| Median pH | 7.1 | 7.2 | 7.3 |
Sources: Water Quality Portal (since 2000); US: USGS Circular 1332. Highlighted: well above the US share.
See what a typical Miami-Dade County well needs
Pre-filled with the Miami-Dade medians. Swap in your own results.
Testing Your Well in Miami-Dade County
The Florida Department of Health in Miami-Dade County oversees private well permitting in the county and investigates suspected contamination. For routine bacteria, nitrate or full-panel tests, use a laboratory certified by the Florida Department of Health.
What to test for in Miami-Dade County:
- Bacteria (total coliform and E. coli) and nitrate, at least once a year (Florida Department of Health recommendation)
- Hardness in grains per gallon (gpg) to size a softener
- Iron and manganese before choosing a filter
- Chloride and sodium, to catch saltwater intrusion
- After any flood, new well work or a change in taste, color or smell
Which tests to order and how: how to test well water.
After a positive coliform test, work out the bleach dose and shock the well and retest 10 to 14 days later.
Nearby Counties
Miami-Dade County borders these counties with published reports:
Broward County
16.4 gpg hardness · Hardness, IronCollier County
18.7 gpg hardness · Hardness, Hydrogen sulfideMonroe County
285.2 gpg hardness · Hardness, IronCounties with similar well water
Not next door, but the groundwater is much the same:
Frequently Asked Questions
Is well water in Miami-Dade County safe to drink?
Not without a test. Arsenic exceeded the 10 µg/L limit in 7% of 100 sampled wells. Only a lab result shows whether your well is one of them; treat or switch to bottled water until you know.
How many homes in Miami-Dade County use private wells?
The Florida Department of Health’s Florida Water Management Inventory (2018 data) found 0.4% of built parcels in Miami-Dade County on private wells, roughly 2,066 properties.
How hard is well water in Miami-Dade County?
15.3 gpg (262 mg/L) in the typical well, based on 173 samples: very hard on the USGS scale, against a Florida median of 12.4 gpg. 99% of sampled wells top 7 gpg, where a softener usually pays off.
Is iron a problem in Miami-Dade County well water?
The median iron level across 157 sampled wells is 0.47 mg/L, above the EPA aesthetic guideline of 0.3 mg/L, and 61% of wells exceed it. Orange staining is common, and an iron filter sized to your test result is the usual fix.
Is arsenic a problem in Miami-Dade County well water?
In 7% of 100 sampled wells, arsenic was above the 10 µg/L drinking water limit. It has no taste, color or smell, so only a lab test finds it; reverse osmosis at the kitchen tap or a whole-house arsenic filter removes it.
Why does my well water smell like rotten eggs in Miami-Dade County?
Hydrogen sulfide was above 0.1 mg/L in 8% of 51 wells tested in Miami-Dade County, so a rotten-egg smell is possible but not typical. The smell is a nuisance rather than a health risk at typical levels.
Does boiling well water make it safe to drink in Miami-Dade County?
For a bacteria problem, yes: boil for one minute (three above 6,500 feet). For anything chemical, no, because evaporation concentrates it. Our boiling well water myth buster explains the difference.
How often should I test my well water in Miami-Dade County?
The Florida Department of Health recommends testing private wells for bacteria and nitrate at least once a year, and again after flooding or well repairs. The Florida Department of Health in Miami-Dade County can explain how to collect and submit samples.
Written by Well Water Advisor Editorial Team.