U.S. Geological Survey groundwater sampling in Navajo County, Arizona, within aquifer 220NAVJ, shows iron was detected in 18 out of 40 samples collected between 2010 and 2019 from 14 wells. Concentrations ranged from 4.3 to 30.6 micrograms per liter, with a median of 7.75 micrograms per liter. None of these results exceeded any federal thresholds.
1. How Iron Enters Groundwater in Navajo County
Natural mineral dissolution in aquifer rock
Iron bacteria thrive where iron minerals dissolve into groundwater due to natural geochemical processes in this region’s aquifer.
Presence of organic material supporting bacteria
Organic matter in the aquifer can promote growth of iron bacteria that oxidize dissolved iron, forming deposits and slime.
Well conditions influencing bacterial presence
Well depth and construction may create environments where iron bacteria colonize by providing oxygen and surface area.
2. Ruling Out Other Causes Before Testing for Iron Bacteria
Visual inspection for rust-colored slime or staining
Check faucets and fixtures for rusty deposits or slimy buildup, common signs of iron bacteria.
Basic water tests for iron and related parameters
Start with home test kits measuring total iron to identify elevated levels that might support bacteria.
Professional lab analysis for confirming bacteria presence
Certified labs can detect iron bacteria specifically, distinguishing from simple iron content variations.
3. Influence of Well Depth and Source Type on Expectations
Shallower wells may have higher bacterial activity
Wells closer to surface levels often have more oxygen, promoting iron bacteria compared to deeper wells.
Sample depth variability across Navajo County wells
Samples analyzed ranged from 554 to 3737 feet deep, indicating wide depth variation affecting iron and bacteria levels.
Groundwater source type affects iron and bacterial growth
Confined aquifers tend to have lower oxygen and iron bacteria presence than unconfined sources.
4. Special Considerations for Larger or Seasonal Households
Higher water usage impacts bacterial growth dynamics
Larger households may see accelerated iron bacteria buildup due to increased water demand and flow patterns.
Seasonal homes risk bacterial growth during inactivity
Periods of stagnation in seasonal properties can encourage iron bacteria proliferation in plumbing systems.
Water system maintenance frequency matters
Regular flushing and monitoring help manage iron bacteria risks, especially for low-use or second homes.
5. Comparing Navajo County Iron Data to Neighboring Regions
Regional geological similarities affect iron presence
Adjacent counties with comparable aquifer geology may share similar iron concentration ranges and bacterial occurrence.
Sampling methods and depths influence data comparability
Differences in sample well depths or laboratory methods can impact how one interprets comparative iron data.
Avoid extrapolating sampled area data to individual homes
Government sampling informs regional conditions but cannot specify a single household’s water quality.
Choosing between treatment options for iron bacteria requires a clear understanding of how iron enters your water, ruling out other causes, and considering your well’s characteristics. Testing your specific water source is essential before selecting a system. The Fleck Iron Bacteria & Slime Filter ships ready to configure and effectively addresses iron bacteria issues common in Navajo County residential wells.
Where this information comes from
Source: USGS groundwater sampling. Sampled 2019-08-23. 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 Iron in the 220NAVJ aquifer (Navajo County): 40 results from 14 wells, median 7.75 ug/L, range 4.3-30.6 ug/L; none above any federal threshold