In Hayward, there are five numbers on almost every mailbox and it can be hard to avoid bad combinations, the Alameda Times-Star said.

The Bay Area has become more ethnically diverse, and that means accommodating practices such as feng shui, an ancient Chinese art of balance.

Real estate agent Lisa Coen, who launched her own feng shui consulting firm several years ago, said she has advised developers on how to make homes marketable to potential buyers who, for instance, would not want to live at the end of a cul-de-sac. Or who would not purchase a home where a door opens onto a staircase.

A rigid county code established the house street numbering system long ago, but builders are beginning to object, the newspaper said.

Coen said feng shui is "all about having the energy meandering through your home rather than having it get stuck."

Sometimes the cheapest solution is to have harmonious street address number combinations, she said.