Fungi Count in Water

Mold and Yeast in Well Water: The Contaminant Most People Never Think to Test For

When people think about well water contamination, bacteria tends to be the first concern. But fungi including mold and yeast can be just as problematic and are far less commonly tested for. Fungi enter well water through many of the same pathways as bacteria: unsealed or damaged well caps, cracks in the well casing, insect infestations, aging filtration systems, and surface water intrusion from nearby wetlands or lakes. The presence of fungi in a well is often a strong indicator that insects have found their way in through a compromised cap or casing, making this test an important diagnostic tool beyond just measuring microbial content.

The health consequences of fungi in drinking water should not be dismissed. Certain molds and yeasts can cause allergic reactions, skin irritation, and respiratory issues. Some fungi produce mycotoxins that can be aerosolized during showering and inhaled, and some of these toxins have been linked to immune suppression and cancer. For immunocompromised individuals, fungal exposure through drinking water carries an even more serious risk.

There is also something important that most people do not know. Certain molds naturally produce antibiotic-like compounds that suppress bacterial growth in well water, meaning a bacteria count test may come back low while mold and yeast are quietly present. A low bacteria count alone does not mean your water is clean. Testing for fungi alongside bacteria gives you a far more accurate picture of your well’s overall microbial health, and we strongly recommend pairing this test with our Total Bacteria Count test.

How It Works

Order your test and we will mail you a sample collection kit with easy to follow instructions. Collect a water sample from your tap and send it back to our in-house laboratory. Results are delivered within 2 to 3 business days from the date your sample arrives.

Understanding Your Results

Every test includes a free consultation with one of our in-house water quality experts. Once your results are in, reach out by phone or email if needed and we will walk you through exactly what was found, what it means for your household, and the right next steps if anything of concern is detected.

This test is recommended for private well owners as part of routine annual monitoring, anyone who has noticed a musty taste or odor in their water, immunocompromised households, anyone whose bacteria count came back unexpectedly low, and well owners who suspect insects may have entered their well through a compromised cap or casing.