In the IEA Global EV Outlook 2022, Norway, Iceland, and Sweden were reported to have the highest electric car shares of the new car market: 86%, 72% and 43%, respectively. Electrification of the transport sector has multiple benefits but has also raised some concerns. Fires in electric vehicles are reported almost daily in the media and social media channels. However, fires starting in an electric vehicle traction battery (i.e., lithium-ion battery) are rare. If the traction battery catches fire, it can be difficult to extinguish since the battery pack in an electric vehicle is generally well protected and difficult to reach. To cool the battery cells, firefighters must prolong the application duration of suppression agent. This results in the use of large amounts of water, that potentially could carry pollutants into the environment. In this work, the analysis of extinguishing water from passenger vehicle fires are reported. Three large-scale vehicle fire tests were performed, the vehicles used were both conventional petrol fuelled and battery electric. Tests were performed indoors at RISE, Borås and the test setup allowed analysis of both combustion gases and extinguishing water. Results show that all analysed extinguishing water was highly contaminated. Additionally, the ecotoxicity analysis of the extinguishing water showed that the extinguishing water was highly toxic towards the tested aquatic species, independent of the traction energy of the vehicle.