June 14, 2026
Rio, WI Water Quality Report 2026
Unlock the full breakdown — detected levels vs. legal limits, plus what removes each one.
Full contaminant breakdown
EPA Six-Year Review compliance monitoring, 2012–2019 — the most recent national compliance dataset EPA has published. See the sections above for more recent violation and PFAS records.
| Contaminant | Avg. detected | Highest sample | Federal limit | Avg. vs. limit |
|---|---|---|---|---|
| DichloromethaneEPA health goal: zero | 2.4 ppb | 2.4 ppb | 5 ppb | 48% |
| Nitrate + nitrite | 3350 ppb | 6690 ppb | 10000 ppb | 33% |
| Nitrate | 3160 ppb | 4420 ppb | 10000 ppb | 32% |
| Fluoride | 1210 ppb | 50200 ppb | 4000 ppb | 30% |
| Radium (combined)EPA health goal: zero | 1.19 pCi/L | 3.28 pCi/L | 5 pCi/L | 24% |
| LeadEPA health goal: zero | 2.62 ppb | 5.2 ppb | 15 ppb (action level) | 17% |
| Gross alpha radioactivityEPA health goal: zero | 1.74 pCi/L | 2.5 pCi/L | 15 pCi/L | 12% |
| Copper | 70.8 ppb | 162 ppb | 1300 ppb (action level) | 5% |
| Total trihalomethanes (TTHMs) | 3.04 ppb | 6.57 ppb | 80 ppb | 4% |
| Barium | 12.8 ppb | 13.2 ppb | 2000 ppb | 1% |
| Styrene | 0.12 ppb | 0.12 ppb | 100 ppb | <1% |
| Haloacetic acids (HAA5) | 0.076 ppb | 0.078 ppb | 60 ppb | <1% |
Also tested, no detections: 1,1,1-Trichloroethane, 1,1,2-Trichloroethane, 1,1-Dichloroethylene, 1,2,4-Trichlorobenzene, 1,2-Dichloroethane, 1,2-Dichloropropane, 2,4,5-TP (Silvex), 2,4-D, Alachlor, Antimony, Arsenic, Atrazine, Benzene, Beryllium, Cadmium, Carbofuran, Carbon tetrachloride, Chlordane, Chlorobenzene, Chromium (total), Dalapon, Dinoseb, Diquat, Endothall, Endrin, Ethylbenzene, Glyphosate, Heptachlor, Heptachlor epoxide, Hexachlorobenzene, Hexachlorocyclopentadiene, Lindane, Mercury (inorganic), Methoxychlor, Nitrite, Oxamyl, PCBs, Pentachlorophenol, Picloram, Selenium, Simazine, Tetrachloroethylene (PCE), Thallium, Toluene, Toxaphene, Trichloroethylene (TCE), Vinyl chloride, Xylenes (total), cis-1,2-Dichloroethylene, o-Dichlorobenzene, p-Dichlorobenzene, trans-1,2-Dichloroethylene.
Reverse osmosis (drinking water)
The treatment category most often matched to dissolved contaminants like lead, arsenic, nitrate, fluoride, and radiological contaminants detected in this system.
Shop reverse osmosis →Whole-house carbon filtration
The treatment category most often matched to disinfection byproducts (TTHMs, haloacetic acids), chlorine taste and odor, and organic compounds detected in this system.
Shop whole-house systems →Source: U.S. EPA Six-Year Review 4 compliance monitoring data (2012–2019), the most recent nationwide compliance dataset EPA has released, reported at the water-system level. A detection is not a violation. “Avg. vs. limit” compares the average of laboratory detections to the federal MCL or action level; individual faucets can differ — household plumbing affects lead and copper, and a state-certified laboratory test of your own tap is the only way to confirm levels in your home. Treatment categories are general matches, not a certification claim for a specific product and contaminant.
Water Utility: Rio Waterworks
Population Served: 1,095 residents
Data Sources: EPA SDWIS + EPA UCMR5
Report Year: 2026
Rio, Wisconsin drinking water is supplied by Rio Waterworks. All US public water systems must test drinking water and report results to the EPA under the Safe Drinking Water Act. This report summarizes health-based violations and PFAS detections recorded in federal databases to help you make informed decisions about home water filtration.
EPA Health-Based Violation History
The following contaminants exceeded EPA maximum contaminant levels (MCLs) at this utility since 2010:
| Contaminant | Violation Years | Filter Solution |
|---|---|---|
| Lead And Copper Rule Revisions | 2024 | Whole House Filters |
Source: EPA Safe Drinking Water Information System (SDWIS), updated quarterly. Health-based violations only.
Should You Filter Your Rio Water?
Even utilities with no EPA violations may have contaminants present below legal limits but above health guidelines. The EPA sets maximum contaminant levels based on what is feasible and affordable to treat at scale -- not necessarily what carries zero health risk. Many independent health organizations recommend filtration for households with children, pregnant women, or immunocompromised individuals regardless of utility compliance status.
Protect Your Rio Home Water
PureWaterGuys.com carries filtration systems designed to protect every tap from lead and copper. We ship to all Wisconsin addresses with free expert guidance on the right system.
Shop Whole House Water Filters →Take the Water QuizFrequently Asked Questions
Is Rio tap water safe to drink?
Rio Waterworks is required to meet EPA federal drinking water standards. However, meeting legal standards is not the same as being contaminant-free. Trace levels of disinfection byproducts, PFAS compounds, and other regulated contaminants are common in US municipal water systems.
Does Rio water have PFAS?
PFAS monitoring data for this utility may not yet be published in EPA databases. We recommend a reverse osmosis system for maximum protection regardless of local results.
What water filter works best for Rio?
A whole-house carbon block filter removes chlorine, chloramines, and many VOCs. For PFAS, arsenic, and nitrates, a reverse osmosis under-sink system provides the highest reduction rates. Take our free 2-minute quiz to find the right system for your home and budget.
Data sourced from EPA SDWIS and UCMR5 federal databases. PureWaterGuys.com is not affiliated with any municipal water utility. Contact your utility's annual Consumer Confidence Report (CCR) for complete local data.