The city of Boulder released its annual Drinking Water Quality Report on Tuesday.

The report is a yearly snapshot on various chemical levels in the city’s drinking water. It also provides insight on the behind-the-scenes aspects of the drinking water, from where it’s sourced to explaining that certain substances are found in the water at safe levels. Barker Reservoir, North Boulder Creek and Carter Lake are among the city’s sources of drinking water.

The report shows there were no levels of substances that violated government standards. However, there were three non-health-based violations.

The first violation stems from the documentation of chlorine levels at different measuring points at the Betasso Water Treatment Plant.

Chlorine residual is continuously measured in treated water with online instrumentation and verified through lab analysis. On four separate dates, the lab verification readings differed by a “greater than allowable margin,” according to the report.

The chlorine levels met regulatory requirements but staff “did not adequately document the steps taken to resolve the discrepancies per state regulations,” according to the report, which later said the violation was resolved as of November 2024 and staff have improved procedures for verifying discrepancies to prevent similar issues in the future.

Another violation was related to how the amount of particles in drinking water, or turbidity, was monitored. The report states turbidity was not measured at a compliance point for 18 hours — longer than allowable timeframe — due to a power failure that impacted the 63rd Street Water Treatment Plant, though downstream measurements showed that turbidity levels were within regulatory limits in this span.

The report states the city corrected the issue and updated a process to improve backup power to avoid issues in the future, and that the issue was resolved as of October 2024.The final violation was an “inadequate backflow prevention and cross-connection control program,” according to the report. In this case, an uncontrolled cross-connection control program means that its possible reverse flow of water leads to contamination from private properties. Backflow prevention mechanisms can keep this from happening.

“In 2024, property owners failed to install five backflow assemblies by state-mandated deadlines. This occurred without the city obtaining approvals for extensions, as required by a state policy change in late 2023. All five of the previously uncontrolled cross connections have been resolved as of November 2024,” the report says.