San Juan River: Mexican Hat
E. coli Monitoring 2019

Update July 25, 2019

The Division of Water Quality (DWQ) detected elevated levels of E. coli at Mexican Hat on May 23, 2019, during routine sampling. E. coli values reached 1203 Most Probable Number (MPN) per 100 mL, approximately three times higher than the health advisory threshold of >409 MPN per 100 mL.

Subsequent sampling by DWQ showed E. coli levels at Mexican Hat decreasing over time. Samples collected from July 13, 2019, to July 25, 2019, were all well below the health advisory threshold. The health advisory was lifted on July 25, 2019.

An advisory for E. coli can be lifted after four consecutive samples over two weeks fall below the advisory threshold.