Are any Iowa state agencies required to do efficiency analysis of their spending? In 2017 North Dakota mandated BCA for water projects seeking state funds--anything similar in Iowa?
To my knowledge, there is no requirement that new regulations be first subject to a cost-benefit analysis in the State of Iowa. This is in contrast to the federal government which under Executive Order 12866 requires that the Office of Management and Budget must conduct a cost benefit analysis before any major regulation can be implemented, and that existing regulations must be subject to periodic evaluation.
The closest requirement in Iowa government is a rule that all tax credits must be subject to periodic review for their effectiveness and to insure that the outcomes of the tax credit are consistent with the objectives. A list of past reports can be found at https://tax.iowa.gov/reports?term_node_tid_depth=80
 This was issued by President Clinton, amending an earlier executive order issued by President Reagan. See https://www.foreffectivegov.org/node/3470 for a good summary of cost-benefit analysis in the federal government.