Air Quality
Drinking Water
Environmental Response and Remediation
Waste Management and Radiation Control
Water Quality
Executive Director’s OfficeUpdate January 8, 2019
Follow-up samples collected by the Davis County Health Department (DCHD) in September, October, and November 2019 showed E. coli levels decreasing from concentrations well above the maximum water quality standard in late September 2019 to well below the maximum water quality standard in November 2019.
Utah uses the Most Probable Number (MPN) method to estimate the concentration of E. coli in a water sample. The presence of a high number of indicator organisms such as E. coli signals a higher probability of pathogens in the water. The threshold of 409 MPN of bacterial density per 100 milliliters (mL) of water relates to a risk factor of 8 illnesses per 1,000 swimmers. As the value of the MPN increases above 409 MPN, the risk of illness if exposed to contaminated waters also increases.
Sample results
- September 26, 2019: >2419.6 MPN per 100/mL
- October 24, 2019: 1119.9 MPN per 100/mL
- November 26, 2019: 93.35 MPN per 100/mL
Update September 13, 2019
The Davis County Health Department (DCHD) issued a health advisory for Maybey Pond on September 11, 2019, after samples collected on August 26, 2019, and September 10, 2019, showed E. coli levels above the maximum water quality standard. Advisory signs have been posted.
Maybey Pond will be monitored on a regular basis during the advisory. The advisory will remain in place until consecutive samples over two weeks fall below the water-quality standard.
Utah uses the Most Probable Number (MPN) method to estimate the concentration of E. coli in a water sample. The presence of a high number of indicator organisms such as E. coli signals a higher probability of pathogens in the water. The threshold of 409 MPN of bacterial density per 100 milliliters (mL) of water relates to a risk factor of 8 illnesses per 1,000 swimmers. As the value of the MPN increases above 409 MPN, the risk of illness if exposed to contaminated waters also increases.
Sample results
- August 26, 2019: 816.4 MPN per 100/mL
- September 10, 2019: 1046.2 MPN per 100 mL
