If you notice a sulfur or rotten-egg smell from your household water in Hillsborough County, this checklist helps you understand what government water quality data show for the local aquifer (112NRSD) and what to do next.
1. What the measured sulfide range means against federal standards—and what it does not
Sulfide was detected in all 13 samples from 11 area wells.
The U.S. Geological Survey sampled wells between 14 and 64 feet deep from 2010 to 2012. Sulfide concentrations ranged from 0.0 to 0.8 mg/L with a median of 0.33 mg/L.
No samples exceeded federal health-based thresholds for sulfide.
All measured sulfide values were below any federal limit. Detection does not indicate a violation or unsafe water. Sulfide primarily affects water odor and taste, not safety at these levels.
2. What to write down before seeking treatment advice
Note the strength and consistency of the sulfur smell at different faucets.
Is the odor present only at cold or hot water taps? Does it vary over time or with water usage?
Record recent water testing results, if available.
Testing for sulfide or related compounds from a certified laboratory gives your specific well data.
Document any water system changes or plumbing work done recently.
This may affect odor sources inside the home separate from the aquifer.
3. The order to rule out causes—starting from cheapest to most detailed
Check for water heater-related odors.
Sometimes hydrogen sulfide gas forms in water heaters, causing smell only in hot water.
Flush your water system thoroughly.
Flush all faucets for several minutes to clear stagnant water that can increase sulfur smell.
Consider professional water testing for sulfide and related compounds.
This confirms your household’s actual levels rather than relying on area aquifer data alone.
4. A worked example: interpreting the local water record
Median sulfide 0.33 mg/L indicates consistent but low-level presence.
While sulfide is detected in all tested wells, levels were relatively low and never above federal standards. This suggests that some sulfur smell might be expected in groundwater but does not confirm your situation.
Range up to 0.8 mg/L means some wells had higher concentrations.
If your well is among those, odor could be stronger. Testing your water is the reliable way to find out.
5. What happens if sulfur smell remains untreated long term
Persistent sulfur smell can be unpleasant and affect water use satisfaction.
While it does not indicate a health risk at these levels, odor can impact taste and household comfort.
Over time, sulfide can cause corrosion and staining.
Its presence may degrade plumbing materials or fixtures if unaddressed.
Closing: What this area data does not tell you
The sulfide levels measured by the U.S. Geological Survey represent samples from multiple wells in Hillsborough County’s aquifer 112NRSD, not your private well. This data cannot determine the concentration or safety in your household water. Only a direct test of your water can provide that information.
For addressing detectable sulfur smell, a Fleck Rotten-Egg Sulfur Smell Filter ships ready to configure and is designed specifically to reduce sulfur odors effectively in residential settings.
Where this information comes from
Source: USGS groundwater sampling. Sampled 2012-11-14. 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 Sulfide in the 112NRSD aquifer (Hillsborough County): 13 results from 11 wells, median 0.33 mg/L, range 0.0-0.8 mg/L; none above any federal threshold