The attached three data files are useful for future researchers who are interested in investigating the composition of electricity load and its underlying demand response potential at U.S. drinking water treatment plants. Each file contains 12 separate spreadsheets that correspond to the 12 months in 2018. Each spreadsheet is organized in the form of a 'process×state' matrix - each row is a key unit process identified in the manuscript entitled 'Assessing the demand response capacity of U.S. drinking water treatment plants' and each column is a state in the U.S. - Each entry (value) in 'US DWTP flows (MGD) 2018' describes the average flow (i.e., daily volume) of drinking water treated by a unit process in a state in a month in 2018. The unit is million gallons per day (MGD). - Each entry (value) in 'US DWTP flows (m3D) 2018' describes the average flow (i.e., daily volume) of drinking water treated by a unit process in a state in a month in 2018. The unit is cubic meter per day (m3/day). - Each entry (value) in 'US DWTP load (MW) 2018' describes the average load of a unit process in a state in a month in 2018. The unit is megawatts (MW).