Diamond Bar Will Stay Split Between Two ZIP Codes

With 1,764 surveys tallied, votes in opposition to consolidating Diamond Bar into one ZIP code outnumber those in favor.

The votes were 978 against, 768 in support.

That means slightly more than 3,000 Diamond Bar addresses will remain in the Walnut 91789 ZIP code, with 80 percent of Diamond Bar in the 91765. For those staying in the 91789 ZIP code, mail will continue to be delivered from the Walnut post office.

In October, residential and business addresses in the 91789 ZIP code were sent a survey by the USPS, asking if they would like to be brought into 91765 with the rest of Diamond Bar. The USPS said that if a majority of the votes were in favor, the change would occur in 2012.

City officials said that postal delays and border confusion are sometimes a result of the split ZIP codes, and the city also loses sales tax income annually from businesses in Diamond Bar's 91789 area. Earlier this year, City Manager Jim DeStefano said that in the past five years, $635,000 in sales tax belonging to the city has been recovered from Walnut, and Diamond Bar has paid $100,000 to Hinderliter de Lamas & Associates to retrieve the funds.

“If the ZIP code was right, we wouldn’t have to spend so much just to collect our money,” Council member Carol Herrera said at the time.