Nitrate levels in the Worden and Ballantine water system have fallen, but warnings to avoid drinking the tap water remain in place.
The Worden Ballantine Yellowstone County Water & Sewer District said Thursday on its website that the most recent tests showed 5.57 milligrams per liter of nitrates in the water, which is well below the federal allowable limit of 10 milligrams per liter.
District officials said they have confirmed the water source is contaminated by surface water, and they haven't where or how so they can mitigate the contamination.
Nitrate usually enters the water system from fertilizers, septic systems, and manure storage or spreading operations. Drinking contaminated water can cause digestive and breathing problems in infants, and its presence can indicate other contaminants harmful to adults, such as bacteria or pesticides.
The Worden Ballantin water district first issued a drinking-water alert for infants in June, after tests showed nitrate levels at 12.4 milligrams per liter.
On Aug. 20, Yellowstone County Health Officer John Felton advised all water users in Worden and Ballantine, including Huntley Project schools, not to drink tap water.
Since then, donations of bottled water have poured into the district's main office in Worden and Huntley Project schools from groups all over south-central Montana.
To donate or distribute water, call Gary Fredericks at 406-696-5507.