While many residents are aware that Foster City shares its 94404 zip code with a small part of San Mateo, few understand the reason why.
Almost 90 percent of 94404 addresses are physically in Foster City, while the remaining ones are in San Mateo, including the Bridgepointe Shopping Center and the buildings surrounding it.
The system dates back to 1963 when the U.S. Postal Service introduced zip codes to help the system sort and deliver mail, but these numbers didn't necessarily follow the strict geographical boundaries of a city. At the time the 94404 zip code was designated to San Mateo, Foster City was in the process being developed.
"The distribution system was set up in 1963 with the original zip codes and that carried forward even through 71," said James Wigdel, USPS spokesman. "As time went by, Foster City of course incorporated (in 1971) and we continued to do the same sort plan or the same distribution."
Foster City has grown since, but postal carriers that deliver to the area are still domiciled in the San Mateo post office at 1630 South Delaware Street. Foster City has a post office where people can mail things and purchase mailing products, but it's not a distribution center.
Keeping it that way is a business decision, explained Wigdel.
"[San Mateo] is where the carrier station is but that's more a matter of efficiency," he said. "It's cheaper to send trucks to one station than to four stations, so it's better to consolidate and dispatch out of one station rather than a small station in Foster City and having an extra truck that would have to go there everyday."
Since the USPS is not taxpayer supported, Wigdel explained that this allows them to operate as efficiently as possible to keep their prices reasonable for the public.
However, many have fought over the years to get Foster City its own separate zip code.
In 2008, Former Mayor John Kiramis, who was vice mayor at the time, introduced a resolution to have 94404 designated solely to Foster City and the city council passed it unanimously. He also contacted several politicians for their help, including then-Congressman Tom Lantos, state Senator Leland Yee, U.S. Senators Barbara Boxer and Dianne Feinstein, and even the White House.
In the end, Kiramis realized it was not that simple. "Pursuing our own zip code would be impractical," he said. "Given the tough economic climate, this would negatively impact the business community - both big corporations and small businesses."
"Every single address, every single utility, every single piece of stationery that has the old zip code – all that stuff get's changed and it's a huge expense when you think about it," said Wigdel.
However, Kiramis said his efforts did fix the problem of 94404 addresses in Foster City showing up as being in San Mateo. He gave the USPS a list of every physical address in Foster City.
"What they did was to change in their computers that the first default for 94404 is in Foster City and not San Mateo," he said.
But some members of the city council claim the shared zip code is still a problem.
"When you order something online and put in the 94404 zip code, San Mateo pops up," responded Linda Koelling via email, who is vice mayor of Foster City. Mayor Kiramis made "a valiant attempt to have it corrected or changed, but did not achieve success," she said.
Kiramis begs to differ. He said the issue there is not all businesses purchase their mailing or address lists from the post office and some may be using outdated information. Even if 94404 shows up as being San Mateo in some business systems, once an order or mail gets to the post office, they know they're delivering to Foster City anyway, he added.
Meanwhile, Wigdel said there haven't been any complaints from customers regarding this or any issues related to the shared zip code.