The Lead in School Drinking Water (LISDW) Dashboard 2018-2020 contains data collected from 2018-2020. Schools voluntarily participated in testing their drinking water during this time. Testing was not mandatory under state law until 2021. We recently cleaned and updated the dataset used by the dashboard due to data quality issues. Issues included duplicated samples and missing data. In this round of data cleaning, we removed 1,330 unique samples from the previous dataset. These samples were either duplicates, contained missing information, or from sites/schools not covered by LISDW program. The removed samples came from 109 schools in 67 school districts.
Cleaning the data has resulted in differences between the updated dashboard and the individual PDF reports on the Washington Department of Health website. Additionally, because some PDF reports contain missing water fixture information and/or sample data, we cannot compare the initial and post-remediation testing results for different fixtures.
The 2018-2020 dataset is also not directly comparable to the data collected from 2022 onwards. This is due to different sampling standards and data collection categories, as well as data quality processes. The older dataset should be interpreted and analyzed on its own. The PDF reports should not be used for data analysis. If you have any questions or concerns, please contact LISDW program at leadfreekids@doh.wa.gov.