By Laura Zuckerman
SALMON, Idaho (Reuters) - Residents of an Idaho town were ordered on Tuesday to boil drinking water for a third day because of sediments in the public water supply that could harbor harmful parasites like cryptosporidium and strains of e-coli bacteria, officials said.
About 500 customers in Idaho City in the southwest part of the state were affected by the boil water order, which is in place indefinitely, state water quality managers said.
Officials with the Idaho Department of Environmental Quality said the municipal water supply in the mountain town was showing unsafe levels of turbidity even after being treated with disinfectants like chlorine.
Turbidity is a measure of sediments and other materials in water that are considered likely to contain harmful parasites and bacteria when at levels above those established by federal safe-drinking water standards, said Todd Crutcher, engineering manager for the department.
The turbidity in the water system is tied to recent heavy rainfall and accelerated snowmelt in the mountainous region, which increased the amount of runoff of soils, woody debris and other materials entering a creek from which Idaho City draws surface water.
The local water supply periodically is out of compliance for turbidity during high water events usually seen in the spring, not winter, Crutcher added.
The timeline for when Idaho City households, restaurants and businesses can safely use tap water will depend on the lessening of runoff into the local creek, he said, adding that was dependent on weather.
“The short-term resolution will come as water flushes through the system and the creek clears,” he said.
Rain is predicted in coming days for the area, which lately saw unseasonably warm temperatures that sped up melting of mountain snows.
Crutcher said Idaho City was taking steps to prevent seasonal contamination issues by installing groundwater wells that will allow it to avoid drawing from surface waters during high flows.
(Reporting by Laura Zuckerman; Editing by Cynthia Johnston and Peter Cooney)