Officials in South Dakota's third most populous city, Aberdeen, are warning residents that their drinking water contains an elevated risk of disease.

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The Aberdeen Water Works Treatment Plant experienced mechanical malfunctions in two filters used to clean water and make it drinkable for residents, resulting in "an increased chance of disease-causing organisms in the drinking water," according to a public notice from the city, The Argus Leader reported Thursday.

The city noticed the malfunctions after a water sample taken July 10 tested at 5.35 nephelometric turbidity units — used to measure the presence of particles in water — which is more than five times the 1 NTU standard for safe drinking water in the state, according to The Argus Leader.

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The city's notice said it's not necessary for residents to boil or decontaminate their water, but that people with severely compromised immune systems, infants and older people are at increased risk of getting sick and should contact their health care providers before drinking the water.

One of the two malfunctioning water filters has been repaired, while the other filter remains offline until it can be fixed, according to the notice.