Cheney's municipal drinking water gets a passing grade

CHENEY — The city’s drinking water has received the federal Environmental Protection Agency seal of approval when it comes to allowed level of contaminants contained with in the system’s eight wells, five reservoirs and 40-plus miles of piping.

According to the city’s annual Consumer Confidence Report for 2020, there were no violations in any of the 13 areas tested, with 11 elements within acceptable ranges. The only two elements outside the “maximum contaminant level (MCL)” — the highest level of a contaminant allowed in drinking water — were iron and manganese, both of which are classified as secondary contaminants tested for aesthetic purposes and not considered a health risk.

According to the report data, iron tested between 0.033 – 0.307 parts per million, with 0.3 ppm being the MCL while manganese came in at 0.053 ppm, with 0.05 ppm the MCL. Both elements lead to water looking yellow, gray or rust colored when the system is disturbed, Cheney Public Works Manager Dan Ferguson said.

“Part of it is the age of the system, part is the nature of the rock formations we’re drawing water from,” Ferguson said in explaining the elements presence. Both settle out as water flow slows down, but reemerge into the system when water is disturbed by something such as opening a hydrant.

Opening hydrants is also part of the city’s flushing procedures, and calls about colored water tend to increase during flushing. But flushing is essential to removing these elements, and Ferguson said the process has been made easier and quicker with the introduction into the city’s system of Well 3 in summer 2019.

The city recently completed its annual flushing program in April, needing only a couple weeks to do so — about two to three times faster than previous years.

“We were pleased with how quick it went this year,” Ferguson said. “Hopefully, every year from now on, as we have the resources, we’ll continue to do that.”

Levels of elements such as haloacetic acids — byproducts of drinking water disinfection — synthetic organic chemicals — runoff from pesticide and herbicide applications — and volatile organic chemicals — found in products such as gasoline, solvents and paints — were not detected in Cheney samples. Arsenic, which occurs from erosion of natural deposits and runoff from glass and electronic production wastes, ranged from undetectable to 2.0 parts per billion — with the MCL set at 10. Levels of chlorine, copper, lead, trihalomethanes — also a byproduct of drinking water disinfection — sodium, nitrate and fluoride were well below not only the MCL but also the MCLG — the goal below which there is no known or expected health risk.

The city adds chlorine as a disinfectant, as well as fluoride — which also occurs naturally in aquifer rock formations. Cheney’s level of the controversial element, which is tested for daily, ranges from 0.333 – 0.92 ppm, with the MCL and MCLG both set at four.

Ferguson said most of the system’s wells run between 0.2 – 0.3 ppm of fluoride, with 1,200-foot-deep Well 5 at Sutton Park the exception at 0.6 – 0.7, which is at or below the state standard of 0.7.

“It depends on where you’re pulling your water from,” Ferguson said. “In the case of Well 5, it’s pulling through a fluoride formation somewhere down there.”

The one area the city came up a bit short in its annual report was its Water Use Efficiency goal. The city’s goal is to account for 90% of the water it produces, and in 2020, it was only able to account for 85.5%.

Ferguson said some of that likely occurred from contractors and out-of-area firefighters coming in and filling their trucks’ water tanks directly from hydrants rather than at the city’s metered water filling facility at the Utility Building. The rest is likely from “pinhole-sized” leaks strewn throughout the city.

“It amounts to about 100 gallons per minute, which isn’t bad in a system as old as ours,” Ferguson said. “But, they all surface eventually.”

John McCallum can be reached at [email protected].