California Code, Health and Safety Code - HSC § 33394

Without the consent of an owner, an agency shall not acquire any real property on which an existing building is to be continued on its present site and in its present form and use unless such building requires structural alteration, improvement, modernization or rehabilitation, or the site or lot on which the building is situated requires modification in size, shape or use or it is necessary to impose upon such property any of the standards, restrictions and controls of the plan and the owner fails or refuses to agree to participate in the redevelopment plan pursuant to Sections 33339, 33345, 33380 and 33381.