City staff links recent brown water to filter project and higher demand; engineers to study flows

Brian, a city water‑works staff member, told the Coldwater City Council during public comment that a multi‑stage filter replacement project begun in February 2023 has coincided with higher-than-expected water demand and caused episodes of discolored water in parts of the system.

Brian said the plant normally treats iron and manganese in four filters; during the renovation one or more filters were out of service and plant operators shortened filter backwash cycles to maintain supply. "I had to shorten that up to about 8 minutes per backwash, and we were only getting out about 28,000 gallons of water a time. So, basically, what I was doing was doubling the amount of iron that I was putting back into the system," he said.

He described the plant as an iron‑and‑manganese removal facility and told the council the discoloration is primarily aesthetic. "It's all aesthetic the way it looks because there's no harm there. It's a secondary MCL, which means there's no contaminant there," Brian said.

City staff told council members that demand in the high‑pressure district has risen roughly 600,000 gallons per day over earlier averages, in part because of new industrial users and a 310‑unit apartment complex on that side of town. That increased draw has changed flow directions and periodically stirred sediment where pressure changes are greatest; high‑service pumps kicking on during peak draw also contribute to pressure surges that can mobilize deposits in mains, staff said.

The plant is sending samples of filter media and water to an outside laboratory in Newport News, Virginia, and will perform spring pressure and flow monitoring to better map the problem. Brian said engineers already are evaluating longer‑term options, including an additional water tower or a package plant on the high‑demand side of town, and cautioned that major infrastructure expansions would likely require multiple years and significant funding. "We don't have it budgeted at this time," he said of large capital options, and added that an engineering study is under way to identify cost‑effective solutions.

Council members and staff asked whether industrial draws could be limited or throttled; city representatives said they can slow variable‑frequency drive startups and otherwise stage pump starts but cannot unilaterally stop a private user's legal water use. Brian told the council the immediate priority is completing the filter work (he reported the filter project is essentially finished and one remaining leak will be repaired) and then flushing problem zones in the spring. He offered to provide routine updates while the city completes testing and monitoring.

The presentation and the council's questions made clear the city considers the discoloration an operational and engineering problem rather than a public‑health contaminant issue; staff said they will return with monitoring results and recommendations for capital improvements if the engineering review indicates them.