In our Dispensers for Safe Water program, which provides access to safe drinking water by installing chlorine dispensers near community water sources in Kenya, Uganda, and Malawi, we verify their use by measuring the adoption rate of chlorine among the households that our dispensers serve. Through the survey conducted in late 2017, we found that our population reached declined from 4.7 million, which is based on surveys conducted for each new dispenser installation during program scale-up from 2012-2016, to 4.0 million people program-wide today.