Floods are the most common type of natural disaster and they impact human health and well-being. In cities such as Dar es Salaam, Tanzania, it is the poorest residents who experience the worst impacts from flooding. Yet although the negative effects of floods on drinking water quality are known, there is little empirical evidence on how they affect water access more broadly. This paper uses interviews from Dar es Salaam's Kigogo Ward to understand perceptions of drinking water source changes during floods. It frames these perceptions in the Sustainable Development Goals, which seek to achieve universal and equitable access to water. Results show that households experience flooding both inside and outside the house and that these episodes impact water quality, accessibility, and availability. In particular, floods can increase contamination, force residents to wait to fetch water, and require them to walk through floodwater to reach water sources. Floods also cause them to discard stored drinking water. These results demonstrate the need for additional research on the impacts of floods on water access.