Public Contract Code § 20418

The check or bond accompanying any proposal or bid which is accepted shall be held by the clerk until the contract for doing the work has been entered into, either by the lowest bidder or by the owners of three-fourths part of the frontage, whereupon the certified check or bond shall be returned to the bidder. If the bidder fails, neglects or refuses to enter into the contract to perform the work, the certified check accompanying his bid and the amount therein mentioned, shall be declared to be forfeited to the city and shall be collected by it and paid into the general fund, and any bond forfeited may be prosecuted, and the amount due thereon collected and paid into the general fund.