Mr Tan Nguan Sen has over 40 years of public service with PUB, having served across key operational departments covering the full water loop. His work has spanned policy development, planning and design, project management, and operations and maintenance.

Mr Tan served as Director of the Catchment and Waterways Department from 2006 to 2014, Chief Sustainability Officer from 2014 to 2018, and Senior Consultant from 2018 to 2024. He played a pivotal role in driving stormwater management, water resource, and sustainability initiatives, including the development of the Active, Beautiful and Clean (ABC) Waters Programme, which integrates waterbodies and waterways into Singapore's urban environment. He has also been involved in the planning and implementation of floating solar PV projects and climate adaptation initiatives, and provides guidance on coastal protection policy and technical solutions.