In 2019, Prague set out its Prague 2030 Climate Plan and Pražské vodovody a kanalizace, a.s. as the operator of drinking water supply and drainage facility in Prague and Pražská vodohospodářská společnost, a.s. responsible for infrastructure management (together with Prague Water) is a natural part of mitigation and adaptation activities. Both companies committed to reaching a net zero operational CO2 footprint in 2035. The carbon footprint of the company will be certified according to the ČSN ISO 14064-1 standard. The manuscript presents a roadmap of the early stage of the project, the calculation of the CO2 footprint and the ISO certification process together with planned mitigation activities. The main goal of the contribution is to share know-how about the application of carbon-wise management principles in a large utility company. This makes the paper useful for worldwide utilities on a similar stage of carbon footprint measurement and reduction.