The popular Diamond Head State Monument has reopened today after closing down mid-day Sunday due to a water outage suspected to have been caused by vandalism.

The Department of Land and Natural Resources said hundreds of people, including many with reservations, had to be turned away Sunday after a park employee noticed no water flowing into the park at 8 a.m., but which has since been restored.

The reservation system was also suspended during that time but is working now.

“That meant no restrooms, no ability for visitors to wash their hands, no bottle filling stations, and no drinking fountains,” said Matt McConnell, the park’s interpretive center manager. “For everyone’s health and safety we had to close the park.”

The problem was eventually isolated to a backflow preventer that appears to have been tampered with, officials said.

DLNR on June 4 was provided with photos showing a water hose siphoning water into an encampment of houseless individuals on the lower slopes of Diamond Head.

The hoses were removed, and officials believe the backflow preventer may have been vandalized in retaliation.

Those who could not use their reservations on Sunday can call the Division of State Parks administrative office Tuesday at 808-587-0300 or file for a refund online.

Updates are available at www.dlnr.hawaii.gov/dsp.