Since 2006, the Iowa Department of Natural Resources has issued 190 advisories at state park beaches because of high levels of microcystin produced by harmful algae. Among those advisories, 142 were issued in the last five years, with a record 37 advisories issued in 2016. Microcystin was also detected in treated drinking water of Des Moines in 2016. While harmful algal blooms (HABs) can have adverse impacts, such as increased drinking water treatment costs and limiting recreational usage of waterbodies, the economic impacts of HABs in Iowa have not been studied. The proposed two-year project will conduct a comprehensive assessment of the economic benefits of mitigating HABs in Iowa. The benefits from improved drinking water safety, recreational opportunities, property values, and water aesthetics will be monetized using state-ofthe-art economic valuation methods. In the first year of the project, we will conduct a survey of Iowa citizens to gauge their awareness and attitude toward HABs and related issues including concerns about lake beach advisories and excessive levels of microcystin in drinking water. The survey data will also be used to monetize the benefits of mitigating HABs. In the second year, we will integrate the housing transaction, lake visitation, and water quality data to quantify the impacts of HABs on property values and recreation activities in Iowa. This study will (1) advance the understanding of socio-economic impacts of HABs to Iowans; (2) support the evaluation and cost-benefit analysis of Iowa Nutrient Reduction Strategy and other conservation programs in Iowa; and (3) provide information for better designing water quality improvement policies in both regional and state scales.