Sewage overflow at Granite Creek leads to closure of park, environmental cleanup

The City of Prescott closed Granite Creek Park in downtown Prescott just after noon on Tuesday, March 21, 2023.  (Cindy Barks/Courier)

The City of Prescott closed Granite Creek Park in downtown Prescott just after noon on Tuesday, March 21, 2023. (Cindy Barks/Courier)

As heavy rainfall and snowmelt caused Granite Creek to swell this week, the sewer manholes located near the creek in downtown Prescott reportedly have overflowed, and the flow has entered the creek.

As a result, parts of Granite Creek Park, located off Sixth Street, have been deemed unsafe for public use and city staff, and the park has been closed since about noon Tuesday, March 21. Signs are posted at the entrances cautioning people not to enter the park.

In a news release on Wednesday, March 22, the City of Prescott reported that cleanup would be done according to state environmental standards.

“When stormflows subside, crews will begin cleaning and disinfecting affected areas per Arizona Department of Environmental Quality (ADEDQ) standards and requirements,” states the news release.

It adds, “Some of the affected areas are unsafe for the public or our crews to enter at this time.”

The news released noted that the Prescott area has experienced two very large storm events this week that each produced large amounts of precipitation.

“The combined effect of these storms and snowmelt has greatly increased flows in many creeks and streams, including Granite Creek,” it added.

The sewer system that is designed to transport household and commercial sewerage to the city’s two wastewater facilities “has been stretched to its maximum capacity due to stormwater inflow,” said the release. “City wastewater crews have been working continuously to stop any flow from leaving the sewer system, however manholes located near Granite Creek have exceeded their capacity, and flow has left the system and entered into the waterway.”

As city storm mitigation operations continue, streets and low-water crossings will be closed, as well as Granite Creek Park.

“We are working with our partners at the state, ADEQ, Arizona Department of Water Resources (ADWR) and Yavapai County, to ensure that the public is safe from excessive surface water flows, and we will continue to respond and mitigate any situation as it arises,” said the news release.

It adds that drinking water supplies have not been impacted. “City of Prescott drinking water is part of a closed system and is safe to drink,” stated the release.

The city will release further information as it becomes available. Future updates will be made available on the city website at, and on the city’s social media on Facebook and Instagram.

Meanwhile, in cooperation the Arizona Department of Environmental Quality, the city reminds residents:

• Not to enter, wade, swim or fish in area waterways until further notice.

• Untreated wastewater associated with sewer overflows can harm your health. Sewerage overflows carry pathogens, bacteria and other compounds that pose a risk to public health and the environment.

• City of Prescott Public Works staff is on-scene conducting clean-up activities and sampling. Vacuum trucks are capturing as much of the ongoing release as possible to reduce the volume going into Granite Creek, the news release stated. “Crews will remain on-site throughout the night and/or until the release from all manholes has stopped,” it said, adding, “The park will remain closed to protect the public.”

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