The City of Boulder says it is notifying all residents and businesses of a drinking water violation that occurred in May or June 2017.

Boulder says testing revealed it exceeded the water quality standard for haloacetic acids, a byproduct of disinfection. The City of Boulder says the violation is not an emergency and does not require using an alternative water source.

Residents and businesses should expect letters about the violation beginning Thursday, November 2nd.

State and federal regulations require testing of haloacetic acids every three months. The average level of haloacetic acids during the third quarter of 2017 was 60 micrograms per liter, which is above the water quality standard.

The letter says the city expects to receive additional violations in January and April 2018 because of the high samples taken in 2017, but says the levels were resolved in June.

According to the Environmental Protection Agency, people who drink water containing haloacetic acids over the regulatory limit over many years may have an increased risk of getting cancer.

You can learn more about haloacetic acids on the EPA's website.

The full letter about the water quality violation is available on the City of Boulder's website.