High utility bills often coincide with cold-weather spells, but many Palo Altans received an unwelcome shock this month when they saw their bills jump by more than $200, in some cases because of a staffing shortage in the Utilities Department.

The unexpected jump has prompted a flurry of complaints from Palo Alto's utility customers, who already pay some of the highest water rates in the area and who saw their gas expenditures spike to new heights. Resident Sara Pickett wrote in a letter to the City Council last week that her family is "dedicated to 'sipping' energy – water, electricity, gas." Her trash bin, she said, is the smallest size possible, and her house on a recent morning was 55 degrees. Yet the bill she received last week was more than $500, up from $175 the prior month.

"How is this possible?" the asked.

She noted that there was an error on the bill that led to a reduction of $50, but the increase remained a puzzle.

"I like to 'do the math' and understand my bill each month so that we can make changes to reduce our utilities," wrote Pickett, who lives in a three-bedroom Eichler house. "I am stumped this month."

While Pickett was stumped, Helen Bobgrove was "appalled" by a bill that left her feeling "as if I have been robbed." Bobgrove noted in an email that there was no evidence that her electric meter was ever read by the meter reader. Elizabeth Browne received a utility bill last week for $526.59, more than $300 higher than her November bill.

"I'm quite upset about this billing, can't afford such an increase on a fixed income, and need to have this rectified," Browne wrote.

Palo Alto officials said there were several possible reasons for the drastic increase, including cold weather and a shortage of meter readers in November and December. Debra Katz, spokewoman for City of Palo Alto Utilities, said the staffing shortage had forced the department to rely on "estimated" rather than "actual" meter readings, with the estimate based on prior year's usage. The estimated readings applied to a small portion of the city, she said. Meter readers typically run 104 routes in Palo Alto, she said. But because of a combination of injuries, vacations and staff turnover, there was a reader shortage that forced the city to estimate utility usage on six routes in November and on two routes in December.

Because the meter-reader shortage coincided with one of the coldest periods in recent memory, the estimated reading was far lower than the actual reading would've been, Katz told the Weekly. Gas usage, she said, was about 20 percent higher than at the same time last year. In fact, it was the highest gas usage that the city has seen in eight years, she said.

Katz said the estimated readings impacted about 1,400 out of the department's roughly 29,000 accounts, with the December estimates applying mostly to the Duveneck/St. Francis area.

Estimated readings, she said, are a long-standing practice, though a very uncommon one that typically goes unnoticed.

"We've been estimating bills occasionally when needed and it has not created a problem in the past," Katz said. "We had a perfect storm of variables here -- no rain, freezing weather and a shortage of meter readers, which means we estimated more bills than usual."

She noted that the staffing shortage will remain for at least the next two months, though estimated bills would be limited to one or two routes. Estimates will be marked with a small letter "e" next to the usage data.

The rash of customer complaints prompted City Manager James Keene to meet with Utilities staff this week to discuss the high bills. This morning, the department offered an explanation on the city's website, which cited the combination of cold weather and "estimated" readings as reasons for the higher bills.

When asked whether the incentives that a lower-than-expected bill can give utilities customers mixed signals, Katz acknowledged that the city will in the future notify customers in advance that the bills they will receive will not be based on actual readings.

In at least one case, the high bill was indeed erroneous. Utility officials discovered that they had made an error on Pickett's bill and ended up reducing it $150.60, to a slightly less eye-popping $374.50. David Yuan, of Palo Alto Utilities, noted in his response that Pickett's gas usage had gone up in December, which was not surprising because the month was "much colder than previous years."