Developing countries have been experiencing a severe health crisis due to the COVID-19 pandemic, and the relationship of this event with access to basic sanitation services is still not well known. In this study, we analyzed sanitation coverage indexes and correlated them with COVID-19 indicators using data from municipalities in São Paulo, which is the most populous Brazilian state and leader in COVID-19 cases. Indicators of 626 municipalities were assessed by state-level and population strata considering water and sewage services. The correlation analyses indicated that a more inadequate coverage of the sewage collection service might be related to the COVID-19 lethality rate in large-sized municipalities (> 100,000 inhabitants).These indicators can be used as subsidies to formulate evidence-based public policies and highlight the need for investments in promoting and monitoring water and sewage services, especially in a pandemic context.