The Navy said it is working on the placement of a new $500,000 groundwater monitoring well near the Red Hill Bulk Fuel Facility to check water quality and evaluate how groundwater moves in the vicinity.

The monitoring well is one of four new wells to be installed in coming months in accordance with the Administrative Order on Consent agreement with the Environmental Protection Agency and State of Hawaii Department of Health.

Concern about the safety of Hawaii’s potable water supplies were heightened after the Navy in 2014 detected a leak of 27,000 gallons from a Red Hill tank, which is situated atop a large aquifer.

The Navy said it broke ground on the well earlier this month, but digging was put on hold due to Tropical Storm Darby.

“Public records confirm that all drinking water remains safe, and this well is more tangible evidence that we are committed to keeping the drinking water safe,” Rear Adm. John Fuller, commander of Navy Region Hawaii, said in a news release.

Construction of the latest monitoring well is expected to be completed by the end of August, the Navy said. The Navy said it will continue to routinely take water samples and send them to an independent accredited commercial laboratory for analysis.

Since 2006, the Navy has invested nearly $200 million to modernize Red Hill, it said.