Reading Fluoride Laboratory Test Reports
Test results show fluoride concentration in milligrams per liter (mg/L).
Reports specify the sample source, sample date, and detection limits.
Concentration reflects the fluoride level in that specific well or tap tested, not a regional average.
Long-Term Effects if Fluoride Levels Are Not Addressed
Prolonged exposure to elevated fluoride can potentially affect dental and bone health.
Water fluoride concentrations above the federal Maximum Contaminant Level (MCL) of 4.0 mg/L are subject to health-based guidelines.
Some wells in San Bernardino County's aquifer have fluoride levels exceeding this MCL according to USGS sampling.
Water with fluoride below this threshold is unlikely to cause health-related fluoride concerns.
Understanding Public-System Records Versus Private Well Testing
Public water systems in San Bernardino County monitor fluoride concentrations regularly and comply with federal MCLs.
USGS groundwater sampling of 523 wells in the N100BSNRGB aquifer showed fluoride detected in most samples, with a median of 0.56 mg/L and a wide range up to 150.0 mg/L.
This sampling does not represent any individual well's fluoride level; private wells require specific testing to know exact concentrations.
Public records provide a regional overview but cannot substitute for a private well’s individualized test.
Changes in Water Quality at the Tap After Using a Fluoride Filter
A dedicated fluoride filter reduces fluoride concentrations in household water by selectively removing fluoride ions.
Filtered water typically shows lowered fluoride levels, improving taste and reducing potential fluoride-related impacts.
Water treated by the Pentair Fluoride Filter ships ready to configure for home use, allowing household control over fluoride content.
The filter is designed for residential applications and is effective for the reported fluoride range in the region.
Fixtures, Appliances, and Water Uses Affected First
Water used for drinking and cooking benefits most immediately from fluoride reduction.
Appliances using water—such as coffee makers or ice machines—may have extended lifespans due to less mineral buildup.
Fixtures like faucets and showers see less direct impact from fluoride but benefit indirectly from improved water quality.
Sources of Fluoride in San Bernardino County Groundwater
Fluoride naturally occurs in minerals that dissolve into groundwater from geological formations in the area.
Well depth influences fluoride exposure, with sampled wells ranging from 24 to 1540 feet deep showing varied levels.
No specific manmade fluoride sources are highlighted for this aquifer by government sampling data.
Summary
The USGS data for San Bernardino County's N100BSNRGB aquifer shows fluoride is commonly present in groundwater with a median level of 0.56 mg/L and some instances above the health-based federal MCL of 4.0 mg/L. To determine fluoride levels in your household water, a specific private well test is necessary. The Pentair Fluoride Filter directly addresses fluoride removal for residential water, helping households manage their fluoride exposure based on their well or tap water fluoride measurements.
Where this information comes from
Source: USGS groundwater sampling. Sampled 2026-05-13. These figures describe groundwater sampled in this area. They are not a test of any individual private well - only a test of that well can establish its own water.
On record: U.S. Geological Survey sampling of Fluoride in the N100BSNRGB aquifer (San Bernardino County): 1497 results from 523 wells, median 0.56 mg/L, range 0.08-150.0 mg/L; 146 above a health-based federal MCL (federal MCL 4.0 mg/L)