ST. PETERSBURG — It wouldn't happen here.That's what St. Petersburg Mayor Bill Foster said Tuesday about Tampa's water problems last weekend.The city, Foster said, not only has backup generators (like Tampa) but also a water tower. So if one of the three pump stations failed, the system would be routed around the failed station.Even in a catastrophic event, he said, the water tower at Crescent Lake would provide pressure for at least 10 hours until a station could come back online.Foster also was incredulous to see and hear news reports blaming a squirrel for the problem."There's no reason why that should happen," Foster said. "A rodent shouldn't be able to knock out a water system."Told of his comments, Tampa officials defended their response.On Friday, Tampa and Tampa Electric Co. officials said the squirrel's fatal decision to chew into a power supply line was merely the first in a "perfect storm" of technical problems that resulted in the loss of power to the plant. Those failures knocked out two independent power supply lines to the plant, as well as a switch that normally turns on Tampa's backup generators."The biggest lesson here is that no utility can plan for every set of circumstances," Tampa Water Department director Brad Baird said. He said that's even a point made this week by the deputy executive director of the American Water Works Association."You can't protect against every foreseeable incident, however remote it might be, and if you could, it would be so expensive as to be infeasible," the association's Tom Curtis said.On Friday, service was restored to everyone in less than an hour, Baird said. But a boil-water alert lasted a day and a half more until testing showed that the water had not been contaminated when the pressure dropped."I challenge any electric or water utility to do better," he said.Aside from having or not having a water tower, Baird said there's another big difference between Tampa and St. Petersburg.Tampa supplies its own water, mainly from the Hillsborough River reservoir, he said, while St. Petersburg repumps water from the regional wholesaler, Tampa Bay Water."Service interruptions can happen in any city; St. Pete is not immune," Baird said. "If Tampa Bay Water were to have a major failure of St. Pete's water feed, it would not be a good thing for them."While hoping he didn't jinx St. Petersburg, Foster had a message for its residents: "I want people over here to feel comfortable."