Helena warns of discolored water as Missouri River plant starts up
Some Helena households may see cloudy water or a slight odor as the Missouri River plant comes online for summer demand. City officials say the water remains safe to use and consume.
Some Helena households noticed cloudy tap water or a slight odor as the Missouri River Treatment Plant began supplementing the city’s water supply for the summer irrigation season. City officials said the change is expected during the seasonal switch and that the water remains safe to use and consume.
The warning comes as Helena shifts into a higher-demand mode that relies on multiple sources, including the Missouri River Treatment Plant east of Helena and the Tenmile Water Treatment Plant west of Helena. When the Missouri River plant is turned on, the city says slight discoloration or odor can occur, usually because water is moving through the system differently and can stir up sediment. The city’s advice is simple: let the tap run until the cloudiness disappears.
Helena’s system faces a sharp summer spike every year. In 2021, the city produced 2.16 billion gallons of water, averaging 5.9 million gallons a day, with a single-day high of 16.6 million gallons. July was the busiest month, at 361.8 million gallons. City meeting notes have said water use rises from about 4 million gallons a day for most of the year to roughly 15 million to 16 million gallons a day in summer, which is why the Missouri River plant typically comes online during irrigation season.
That seasonal role is nothing new. City planning documents say the Missouri River Treatment Plant was built in 1958, and the facility is designed to help the city keep up when lawns, gardens and other warm-weather demands push the system harder. Helena’s 2023 consumer confidence report says the plant operates as a zero-discharge facility because backwash water is reused for managed irrigation and recirculated, while state-certified staff monitor and treat the water through SCADA controls.
The city has also been managing the system around maintenance work. In October 2025, Helena announced a multi-phase project that limited Tenmile output and brought in Missouri River water to help keep service steady, with construction paused during summer because of irrigation demand. That same operating pattern is what makes a brief change in taste, odor or color familiar in Helena, even if it can be alarming at the sink.
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