Cal. Water Code § 74870

The bonds as issued may be sold at such times and in such amounts as the board deems expedient, after a notice inviting bids therefor has been published in the district pursuant to Section 6062 of the Government Code. A certified check payable to the district for at least 2 percent of the amount of the bonds offered shall accompany each bid, conditioned that the bidder will accept and pay for the bonds bid for if awarded to him, otherwise such check shall be forfeited to the district and the amount thereof paid into the treasury. If no bids are received the bonds offered may be sold at private sale.