Turtle Bay announced Thursday that treated wastewater had accidentally overflowed onto its golf course on Sept. 18.

The announcement is a requirement.

The Turtle Bay Wastewater Treatment Plant reported the spill that day to the Department of Health of an estimated 26,000 gallons of treated R2 wastewater ponded near the 17th tee box of the Fazio golf course at the resort.

It occurred between 1:30 p.m. and 2:15 p.m.

At a minimum, 300,000 gallons of R2 wastewater is used to irrigate the golf course daily.

Turtle Bay explained that an irrigation valve was inadvertently left closed, which caused an unused section of line to backfill with treated wastewater.

Crews took measures to allow the irrigation water to dissipate through the system, and the area was treated as a precaution with a light chlorine solution. The water that ponded soaked into the ground.

No wastewater flowed into any stream or ocean areas, the company said.

Testing is ongoing to determine whether any contamination of the affected area occurred.

Turtle Bay began efforts to “confirm protocols to make sure the valve remains in the proper position” to prevent further incidents by Aqua Engineers, which operates and maintains the plant and related systems.

The wastewater treatment plant normally discharges the treated wastewater into the golf course’s irrigation ponds, which are features of the golf course. Signs indicate the ponds contain R2 water.