HILO, Hawai'i — The latest tally of damage to Big Island county water systems from the Oct. 15 earthquakes is more than double original estimates, with inspectors finding cracks and leaks to reservoirs and distribution lines that will cost more than $10 million to fix.

The most expensive individual items are an estimated $2 million in repairs for two 50 million-gallon reservoirs above Waimea. One of the reservoirs had to be completely drained, and a second was partially drained when leaks were found after the earthquakes.

That reduced the amount of water that can be stored to serve the area, and the slim reserves combined with the relatively dry weather in the Waimea area recently may mean the county will have to issue water conservation notices soon, said Quirino Antonio, deputy manager of the Department of Water Supply.

"Pray for rain," said Antonio. The county still has one well and an intact 50 million-gallon reservoir to store surface water for the Waimea system, which serves 3,000 to 4,000 customers.

It will cost $1 million to repair a single 250,000-gallon steel tank at Waipunaula in South Kona that was damaged in the earthquakes, and $350,000 to $750,000 each to repair 14 concrete reservoirs that were damaged in Kohala and Kona, according to a report released yesterday by the county Department of Water Supply.

Antonio said the $10 million in damage approaches the total amount the water department would spend in an ordinary year on capital improvements to the system.

Antonio said he doubts the department would raise water rates to pay for the repairs. If necessary, the department might schedule the repairs over time to avoid any need for a rate increase, he said.

The total amount of damage from the magnitude 6.7 and 6.0 earthquakes is expected to top $200 million, including $17 million to county facilities. County officials were planning a briefing today to outline the progress that has been made since the earthquakes, and to review work still to be done.

Preliminary damage estimates released by the University of Hawai'i show university facilities statewide suffered about $2.5 million in damage.

Most of the damage was found at the university's flagship Manoa campus or its satellite facilities, including UH-Manoa's Institute of Astronomy, Mauna Kea Observatory and Haleakala Observatory. Damage also was found at UH-Hilo, Maui Community College, Hawai'i Community College, Leeward Community College and Honolulu Community College.

"Even here at Manoa, as much damage as there was, it wasn't serious enough for anybody to stop their operations," said Jim Manke, UH-Manoa spokesman.

The Institute for Astronomy's Mauna Kea Observatory on the Big Island suffered "possible structural damage" to a rotating enclosure and mechanical damage to the mount system. Damage there was estimated at $80,000. On Maui, at the Haleakala Observatory, the UH 1.8 Meter Pan-STARRS Telescope suffered about $100,000 in damage.

Hawai'i County officials yesterday also said more work is still to be done on homes that were deemed unsafe to occupy, or that had portions that were unsafe.

The county issued 67 red tags indicating that buildings were not safe to occupy, and issued another 227 yellow tags that mean portions of those buildings cannot be used until repairs are made.

The owners will need licensed contractors to repair those structures and get the county to remove the tags, said Noelani Whittington, community outreach coordinator for the county Department of Public Works. The average cost to restore the homes that were issued red tags "ranges upwards of $50,000," county officials said.

Staff writer Loren Moreno contributed to this report.

Reach Kevin Dayton at kdayton@honoluluadvertiser.com.