PORTLAND, Ore. (AP) — Portland officials are once again preparing to flush millions of gallons of treated water because someone urinated in a city reservoir.

Water Bureau Administrator David Shaff said 38 million gallons will be discarded after a 19-year-old was videotaped in the act Wednesday.

Three years ago, the city drained a 7.5-million-gallon reservoir at the same Mount Tabor location in southeast Portland.

The open reservoirs hold water that's already been treated and goes directly into mains for distribution to customers.

The urine poses little risk — animals routinely deposit waste without creating a public health crisis — but Shaff said he doesn't want to serve water that was deliberately tainted.

"There is at least a perceived difference from my perspective," Shaff said. "I could be wrong on that, but the reality is our customers don't anticipate drinking water that's been contaminated by some yahoo who decided to pee into a reservoir."

Water quality test samples have been taken from the reservoir, with results due Thursday. The water will be drained into the sewage system that eventually dumps into the Columbia River.

In the meantime, Shaff said the city has plenty of water to meet demand.

"It's easy to replace those 38 million gallons of water," Shaff said. "We're not in the arid Southwest; we're not in drought-stricken parts of Texas or Oklahoma."

The incident occurred shortly after 1 a.m., when Water Bureau security personnel noticed three men on camera at Mount Tabor Reservoir No. 5. One was seen on video urinating through an iron fence, officials said. Minutes later, two other young men attempted to scale the fence.

The three men, whose names have not been released, were cited for trespassing and excluded from Mount Tabor Park. A 19-year-old was cited for public urination.

The kidney-shaped reservoir built in 1911 is drained for cleaning each spring and fall. The spring draining was done about three weeks ago, the Water Bureau said.

The reservoir is one of five the city is in the process of replacing with underground storage to comply with federal regulations.

Floy Jones, co-founder of the group Friends of the Reservoirs, criticized the decision to drain the reservoir, saying there's no evidence any urine reached the water and it wouldn't harm anyone if it did.

"It's extremely wasteful," she said.

The man who urinated into Portland's water supply in June 2011 eventually pleaded guilty to misuse of a reservoir and was sentenced to community service.

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