With the rapid growth of Bangalore city over the past two decades, the demand for water has increased significantly. As the commercial and industrial hub of Karnataka state with a population exceeding 10 million, the water demand by the Commercial, Industrial and Institutional (CII) sector in Bangalore is substantial. The city depends primarily on two sources of water – 1) local groundwater, and 2) surface water imports, from the river Cauvery pumped from a distance of about 100 km. With depleting groundwater in parts of the city and legal limits on water imports from the Cauvery, the city needs to efficiently and equitably manage its water to meet the needs of different sectors ensuring sustainability of the resource and resilience against drought and climate change. However, there are critical knowledge gaps on how much water is actually used by different sectors, particularly the CII sector. This report discusses the various sources of data related to water use by the CII sector and their limitations. We provide an estimate of CII water use for Bangalore city and discuss potential solutions that can help address the data gaps.