Hooton also said that a new treatment plant and aqueduct at the Point of the Mountain would allow sending water in any direction around the valley from three different water plants. Also, he said his agency had access to numerous wells and other sources of water, again providing redundancy to help deliver supplies even if some major sources or pipelines go down.

Despite all those preparations, Hooton said in 2006 that it is always a good idea for residents to have some water stored. "Everybody needs to have a 72-hour kit and needs to supply themselves with water. They should have a gallon per day per person, plus some more for pets. You don't need an earthquake to need that. Something simple can happen like the water being off for a main break."

Dams and reservoirs

Related to water service is how well dams perform. Fortunately, federal and state actions over the past 15 years brought seismic upgrades to the major dams perched above Utah's populated areas.

"I am pretty comfortable that they could handle the seismic loading" from the big earthquake, state dam engineer Dave Marble observed in 2006.

But if a 7.0 had occurred before recent seismic upgrades, Marble said many might have failed and caused devastating floods downstream. Pineview Dam could have threatened Ogden, Mountain Dell could have threatened Salt Lake City and Deer Creek could have threatened Provo. Now all are considered seismically sound.

Breaks by any of them, of course, also would have devastated local water supplies.

Marble said a few smaller dams, which had to wait for upgrades while money went to higher-priority dams first, still would give officials anxious moments in an earthquake. But he thought in 2006 that most of them would also handle an earthquake.

He said that even if some of the dams that worry him the most did break, they are small enough "that they would not be catastrophic."

Electric power

Projections in 2006 also foresaw long restoration periods for electricity.

Of 241,000 households that initially lose service, projections said 176,000 would still be without it after three days; 100,000 would be without it after a week; 31,000 would still be without it after a month; and about 300 would still be without it after 90 days.

Dave Eskelsen, spokesman for Utah Power, said in 2006 that the key to how long power would be out is whether some large, custom-manufactured items like certain transformers failed or not.

"Often, you only need one — so the manufacturer builds it for you," so Utah Power would not buy many spares for emergencies, Eskelsen said. If such major components do go out, power in some areas would be out for extended periods.

Otherwise, Eskelsen said, "The network itself is able to weather some kinds of ground shaking pretty well."