S1 Data -

Given nearly one third of sub-Saharan Africa’s population lack access to an improved water source that is available when needed, service continuity restricts access to safely managed services. Household surveys, water regulators, and utilities all gather data on service continuity, but few studies have integrated these disparate datasets to quantify continuity-related risk factors and inequalities. This study aimed to assess the added value of utility and regulator data for international monitoring by assessing factors affecting piped water availability in urban and peri-urban Zambia. Household ‘user’ data from the 2018 Demographic and Health Survey (n = 3047) were spatially linked to provider data from an international utility database and regulator reports. Multilevel modelling quantified provider-related and socio-economic risk factors for households reporting water being unavailable for at least one day in the previous fortnight. 47% (95% CI: 45%, 49%) of urban and peri-urban households reported water being unavailable for at least one full day, ranging from 18% (95% CI: 14%, 23%) to 76% (95% CI: 70%, 81%) across providers. Controlling for provider, home ownership (odds ratio (OR) = 1.31; p p p p p p