Santa Cruz County officials have updated affordable housing rules to help promote the building of smaller units. The rewrite of the Affordable Housing Program was approved by the Board of Supervisors yesterday following a year-long effort. Developers will now be required to pay a baseline fee of $2 per-square-foot. The fee will increase with a project’s square footage. The collected fees will provide an additional $650,000 in annual revenue. Planning officials will report on the impact of the update in two years.