Bacteria was found in a hydration station at U.S. Open host course Erin Hills on Thursday.
Health officials in Wisconsin said that evidence of E. coli bacteria was found in a station.
The Washington Ozaukee Health Department identified the bacteria in a drinking water sample collected from the hydration station connected to a well near the 12th hole, according to a news release sent to media.
While there were no reports of anyone falling ill at Erin Hills, the health department did say people who consume the tainted water could become sick with symptoms of gastrointestinal illness such as diarrhoea, vomiting, fever, nausea and abdominal cramps.
Complimentary bottled water will be provided at all hydration stations beginning Friday, and for the remainder of the event.
The USGA was under a lot of pressure to ensure this year's U.S. Open was controversy-free after Dustin Johnson was penalised one stroke last year following a questionable ruling.