BELOIT, Wis. -- The Rock River is on the rise and as water levels crept up last week, the main branch of the U.S. Post Office in Beloit was forced to pack up the PO boxes and head for higher ground.

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The downtown Mill Street location has yet to flood, but the streets around it look more like swamps. With the water several inches deep, postal officials determined it was too dangerous for customers to drive through, WISC-TV reported.

"We've been pumping the parking lot pretty much nonstop this week, and doing a lot of sandbagging like everybody else," said Sue Janczak, manager of Postal Operations.

Mail carriers are making deliveries, although they are forced to drive through water to do it.

"We've been coming out the back side (of the office) and parking them on higher ground," said Janczak. "We're not leaving them in the garage which is one of the lowest points."

Customers who need to pick up their boxed mail or ship a package are being redirected to Hackett Elementary School on Grand Avenue. The hours are limited though -- between 9:30 a.m. to 3:30 p.m. each day -- which is a bit inconvenient for some customers.

"I was hoping they would keep it open until normal post office hours," said Nachiket Karnik. "If they have to move, I understand."

Janczak said that the mail is safe. Almost anything that could be damaged by water, should it continue to rise, has been moved to higher shelves. She also said that all mail being kept at the elementary school is safe as well. She said it's under lock and key as well as the watchful eye of an alarm system.

Starting on Tuesday, customers will also have the benefit of another location to buy stamps and ship packages. A mobile unit has been brought in from Chicago and is set up in the Eclipse Parking Lot, which is at the old Beloit Mall. It will be open normal post office hours, from 9 a.m. to 5 p.m.

The blue collection boxes outside the main post office are closed for the time being, but others elsewhere in the city are open, WISC-TV reported.