Cal. Pub. Cont. Code § 20421

The owners of three-fourths of the area of lands liable to be assessed, or their agents (who shall make oath that they are the owners or agents) are not required to present sealed proposals or bids, but may within 10 days after the first publication, or first posting if there is no publication, of the notice of the award of the contract, elect to take the work and enter into a written contract to do the whole work at the price at which the contract has been awarded. All work done under the written contract is subject to regulations which may be prescribed by ordinance of the legislative body.