City Of St. Helena Fails Drinking Water Standard

ST. HELENA, CA — The city of St. Helena's water system recently failed a drinking water standard, city officials said Thursday evening.

"Although this is not an emergency, and our water is safe to drink and use, as our customers, you have a right to know what you should do, what happened, and what we are doing to correct this situation," said Jo Ann Burkman, acting chief operator for the city's water division.

The city routinely monitors its distribution system for the presence of drinking water contaminants. Testing results received for Nov. 10, 2020, and March 9, 2021, showed the system exceeded the standard or maximum contaminant level —MCL — for haloacetic acids, or HAA, Burkman said.

The standard MCL for haloacetic acids is 60 ug/L; the running annual average for the LSWTP Distribution System in the fourth quarter of 2020 measured 68 ug/L, Burkman said.

What Should Customers Do?

• Customers do not need to boil their water or take other actions, the city said.
• This is not an emergency, according to the city. If it had been, customers would have been notified immediately. Tests taken during this same time period did not indicate the presence of bacteria in the water.
• The current notification was not for inadequately treated water; however, it is important to note that if water is inadequately treated it may contain disease-causing organisms. These organisms include bacteria, viruses and parasites that can cause symptoms such as nausea, cramps, diarrhea and associated headaches. These symptoms, however, are not caused only by organisms in drinking water, but also by other factors. Customers who experience any of these symptoms and they persist, may want to seek medical advice.
• People with severely compromised immune systems, infants, and some elderly may be at increased risk. These people should seek advice about drinking water from their health care providers. General guidelines on ways to lessen the risk of infection by microbes are available from U.S. Environmental Protection Agency Safe Drinking Water Hotline at 800-426-4791.
• Customers with other health issues concerning the consumption of this water may want to consult with their doctor.

What Happened? What Is Being Done?

The Glass Fire of September and October 2020 destroyed the pre-oxidant sodium permanganate building structure and injection system for the Louis Stralla Water Treatment Plant, resulting in increased organic and non-organic loading in the source water. To ensure sufficient disinfection of the public drinking water, operations staff increased the chlorine dosage and chlorine points of injection.

"The increased chlorine dose resulted in higher levels of disinfectant Haloacetic Acids byproducts, or HAA5," Burkman said.

The city received a water quality citation for exceeding the MCL in samples taken Nov. 10, 2020, at Knoll Place in the Knoll/Meadowood booster pump for Zone 4, and March 9 in storage tanks I and II of the distribution system at Knoll Place, 3029 Helena Highway.

The citation was for failure to comply with state water regulations by ending the fourth quarter of 2020 measuring 0.068 ug/L, above the Maximum Contaminant Level of 60 ug/L, and exceeding the MCL in the first quarter of 2021 at four sites: (1) Knoll Place at 29.6 ug/L; (2) 3029 Helena Hwy at 63.7ug/L; (3) Storage Tank I 96.4 ug/L; and (4) Storage Tank II 114.57 ug/L.

To reduce the level of disinfection byproducts, the city is working to:

• Restore the sodium permanganate chemical feed system with an estimated completion date of May 15;
• Replace the mixer in Tank II, which was installed Thursday, April 8;
• Continue Volatile Organic Carbon — VOC— sampling; and
• Continue jar testing.

Additionally, the LSWTP storage tanks and the underground Clearwell structure, which stores finished potable water, have been professionally inspected and were being cleaned Thursday and Friday, Burkman said.

View the full notice from the city of St. Helena: