Test: Harvey floodwaters contain hugely unsafe amounts of bacteria

The three water samples for total coliform bacteria were 57,000 CFUs, 43,000 CFUs and 45,000 CFUs. (Colony-forming units, or CFUs, estimate the number of bacteria or fungal cells that have the ability to multiply in a sample.) The EPA standard for recreational water, which applies to swimming pools, is less than 100 for total coliform, said Sevukan.

Hearing these numbers, Wilma Subra, president of the Subra Company, an environmental consulting firm, audibly gasped.

“First of all, the drinking water for coliform should be non-detect and here you have these very, very elevated levels,” she said. “These levels indicate the potential for sewer plant malfunction or sewer plant continuing to discharge untreated or partially treated waste.”

Along with the coliform analysis, Sevukan had three sample test results for E. coli, which is part of the total coliform number: 8,600 CFUs, 3,700 CFUs and 6,300 CFUs. Again, the EPA drinking water standard for E. coli is zero, noted Sevukan, though the EPA’s recreational water standard is also zero for E. coli.