As stated by the OECD, “water security in many regions will continue to deteriorate due to increasing water demand, water stress and water pollution.” Indeed water supply and sanitation (WSS) utilities in many countries are already and increasingly faced with pressing water risks which include the risk of “water shortages (including droughts), water excess (including floods), inadequate water quality mainly due to pollution, as well as the risk of undermining the resilience of freshwater systems (rivers, lakes, aquifers)” (OECD, 2013). These risks are exacerbated by climate change which increases the magnitude and frequency of extreme events. As a matter of fact, WSS utilities are already commonly faced with qualitative and quantitative pressures on water resources, the intensity of which varies over time and space. These developments, as well as the financial constraints on the services (limited capacity to increase the price of water/sanitation in an inflationary context and strong constraints on post-covid public finances) are all elements that must be addressed to ensure the sustainability and resilience of the services in an environment now marked by threatened water security. This paper firstly presents an inventory of drinking water and collective sanitation assets in France. It identifies renewal needs as well as investment gaps thus underlining the magnitude of the infrastructure related challenges that the sector needs to address to ensure the sustainability and quality of water and sanitation services. In addition, this paper includes elements for evaluating the broader cost of water security. Indeed, in a context where climate change exacerbates water risks and encourages improving the resilience of water and sanitation services, the financial issues related to the proper management of assets cannot be limited to the sole issue of grey infrastructure renewal. It is also necessary to assess the financial challenges of water security through the management of water-related risks such as droughts, floods, and the preservation of aquatic environments. Thus, an assessment of environmental costs and damages generated by water and sanitation services is also provided to complete the analysis.