OUT WITH THE OLD, IN WITH THE NEW–The water tank sitting in the hills of Thousand Oaks near Lone Oak Drive, as seen from the parking structure of the Thousand Oaks Civic Arts Plaza, will be replaced. WENDY PIERRO/Acorn Newspapers In a couple of months, residents near the Thousand Oaks reservoir water tank on Lone Oak Drive will notice some activity on their hill that will make them safer in the event of a sizable earthquake.

The 7-million-gallon tank that rises above the hill and sits behind dozens of homes was built in 1965. It’s not considered seismically safe. The vintage steel tank will be replaced with two concrete tanks that will be buried into the hillside and also store 7 million gallons.

“The old tank is showing wear,” said Eric Bergh, Calleguas Municipal Water District manager of resources.

The $13-million reservoir replacement should begin at the end of February and be completed in the autumn of 2012, Bergh said.

The original tank could have been retrofitted and repainted, but the new tanks will enable more water pressure, making them more compatible with the hydraulic pressure zone where the tanks are connected. Access to the tanks will also be improved, as will an emergency overflow and drain, electric controls and security.

“The buried reservoir will immensely improve the aesthetics,” Bergh said.

Before the old water tank is demolished, a new 2.6-million-gallon reservoir will be built next to it. Then the old tank will be removed and a 4.4-million-gallon buried reservoir will take its place.

—Nancy Needham