Arsenic in Central Florida Water
Arsenic occurs naturally in groundwater throughout Florida. The Floridan Aquifer, which supplies most of Central Florida's water, contains varying levels of arsenic depending on the depth and location of the well. While Orlando's municipal water treatment facilities monitor and manage arsenic levels, private well owners in the Orlando area should be aware of the risk:
- Municipal water: Orlando's water system consistently reports arsenic levels below 2 ppb — well under the EPA action level of 10 ppb. Treatment processes remove naturally occurring arsenic from the aquifer before distribution.
- Private wells: Arsenic levels in private Central Florida wells range from 0-40+ ppb. Some wells in Orange, Seminole, and Osceola counties have been found to exceed the EPA limit. Testing is essential before choosing a treatment.
- Health effects: Long-term arsenic exposure is linked to skin, bladder, and lung cancer. The EPA estimates that 10 ppb arsenic in water could cause 600-2,400 excess cancer cases per year per million people. Short-term exposure causes nausea, vomiting, and nerve damage.
How RO Removes Arsenic
Reverse osmosis removes arsenic through the same physical barrier mechanism that removes other contaminants. The 0.001-micron RO membrane blocks both arsenite (As+3) and arsenate (As+5) — the two forms of arsenic found in water. Here is the removal efficiency by form:
| Arsenic Form | RO Removal | Notes |
|---|---|---|
| Arsenate (As+5) | 93-99% | More easily removed by RO |
| Arsenite (As+3) | 85-95% | Slightly harder to remove |
| Combined (typical well water) | 90-98% | Typical Orlando-area well water |
The pre-carbon filter in a 5-stage RO system also helps by oxidizing some arsenite to arsenate, improving overall removal. For wells with high arsenic (above 50 ppb), a combination of RO plus a specialized arsenic filter may be necessary to achieve safe levels.
RO vs. Other Arsenic Treatments
Here is how RO compares to other arsenic removal methods:
| Method | Arsenic Removal | Cost (Orlando) |
|---|---|---|
| Reverse Osmosis | 93-99% | $800-1,500 installed |
| Activated alumina | 90-95% | $500-1,000 installed |
| Ion exchange | 85-95% | $600-1,200 installed |
| Distillation | 99% | $150-300 + $30/year electricity |
Bottom line: Reverse osmosis removes 93-99% of arsenic from drinking water and is the most effective residential treatment for combined arsenic removal. For Orlando municipal water, arsenic levels are typically well below the EPA limit of 10 ppb. For private wells in Central Florida, arsenic can exceed safety standards — testing your well water is essential, and an RO system is the best treatment if elevated levels are found.
Arsenic in Orlando-Area Well Water
If you have a private well in the Orlando area, arsenic testing is essential. Here is what Orlando well owners need to know:
Arsenic prevalence: The Florida Department of Environmental Protection reports that 5-15% of Central Florida private wells have arsenic levels exceeding the EPA action level of 10 ppb. Orange County wells show particularly high arsenic in certain areas, including parts of southeast Orlando and Lake Nona.
Well testing frequency: Test your well for arsenic at least once every 3 years, even if previous tests were clean. Arsenic levels can fluctuate based on seasonal groundwater conditions, nearby agricultural activity, and natural aquifer variations.
Well treatment options:
- Under-sink RO for drinking water only: $800-1,500 installed
- Well-point arsenic removal system: $2,000-5,000 installed
- Whole-house RO: $3,000-8,000 installed (only for severe contamination)
Bottom line: For Orlando-area well owners, arsenic testing is essential. 5-15% of Central Florida wells exceed the EPA limit of 10 ppb. An under-sink RO system removes 93-99% of arsenic and costs $800-1,500 installed. Test your well at least every 3 years, and treat with RO if elevated levels are found. For municipal water users, arsenic levels in Orlando are consistently well below the EPA limit.
Health Effects of Arsenic Exposure
Understanding the health risks of arsenic in drinking water helps explain why RO treatment matters. Short-term exposure above 500 ppb causes nausea, vomiting, and nerve damage within hours. Long-term exposure above 50 ppb causes skin lesions and peripheral neuropathy over months to years. Exposure between 10-50 ppb increases cancer risk for skin, bladder, and lung cancers over decades. Even levels just above the EPA action level of 10 ppb carry measurable health risks over a lifetime. For Orlando families with elevated well water arsenic, the risk is real and cumulative.
Treatment Comparison for High-Arsenic Wells
For Orlando-area well owners with arsenic levels above 50 ppb, here are the most effective treatment options:
| Treatment | Removal | Best For |
|---|---|---|
| RO under-sink | 93-99% | Drinking water only |
| Activated alumina | 90-95% | Well water, moderate arsenic |
| Ion exchange | 85-95% | Well water, low-to-moderate arsenic |
| Whole-house RO | 93-99% | Severe contamination, all water uses |
For most Orlando well owners, an under-sink RO system is sufficient and cost-effective. Whole-house RO is only necessary for wells with arsenic levels above 200 ppb or for families concerned about arsenic exposure during showering and bathing.
Quick Arsenic Check
If you have a well in Central Florida and want to know your arsenic level quickly: test your water through your county health department or a certified lab. The Florida DEP maintains a public database of well water test results by county. Orange County well owners can also request a free arsenic screening through the Orange County Utilities program for eligible residents. Early detection is the best defense against arsenic exposure.
How much arsenic does reverse osmosis remove?
Reverse osmosis removes 93-99% of arsenic from drinking water. The RO membrane physically blocks both arsenite and arsenate forms of arsenic. For homes with elevated arsenic levels, an RO system is one of the most effective residential treatment options available, along with specialized arsenic removal filters.
Is there arsenic in Orlando water?
Orlando's municipal water from the Floridan Aquifer generally has low arsenic levels below the EPA action level of 10 ppb. However, arsenic can be present in well water throughout Central Florida at levels that exceed safety standards. If you have a private well, testing for arsenic is essential.
What forms of arsenic does RO remove?
RO removes both forms of arsenic: arsenite (As+3) and arsenate (As+5). Arsenate is removed at 93-99% efficiency by RO membranes. Arsenite is slightly harder to remove but still achieves 85-95% removal with a standard RO system. The pre-carbon filter also helps convert some arsenite to arsenate, improving RO removal.
How do I test my water for arsenic in Orlando?
Test your water through: (1) your municipal water quality report (annual Consumer Confidence Report), (2) a professional lab test ($50-100, recommended for well owners), or (3) a home arsenic test kit ($15-25). For well owners, include arsenic in your annual water test — it is one of the most important contaminants to monitor in Central Florida groundwater.
What is the EPA limit for arsenic in drinking water?
The EPA maximum contaminant level for arsenic in drinking water is 10 parts per billion (ppb), set in 2001. The WHO guideline is also 10 ppb. No level is considered completely safe, but 10 ppb is the threshold at which long-term exposure increases cancer risk.