Attard

*1069 The plaintiffs in this action, Paul and Tamara Attard (Attards), formulated a creative solution to circumstances constraining development on their two properties in Contra Costa County (County), but they failed to obtain the necessary regulatory approvals for their plan. Notwithstanding that failure, the county issued them permits to develop the properties, including a permit for construction of an 8400-square foot home. By the time the county discovered its error and notified the Attards, they had made substantial progress toward installing a foundation for the new home on *1070 one of the properties. The county nonetheless revoked the permits, a decision that was affirmed by the county Board of Supervisors (Board).

The Attards filed a petition for writ of mandate challenging the revocation. In the petition, they contended the County was precluded from revoking their permits under the doctrines of vested rights and equitable estoppel. In addition, they contended they were exempt from local regulatory authority under the doctrine of sovereign immunity and were denied due process by the evident bias of one Board member. The trial court denied the writ petition, and we affirm…