water wagon; water tender
A vehicle equipped with a water tank, used for supplying water in firefighting, construction, or disaster relief.
The fire station is equipped with a water tender.
A water wagon was dispatched to the area with a water outage.
タンクローリー is a tank truck for transporting liquids like fuel or chemicals; 給水車 is specifically for water supply, often in emergency or construction contexts.
Compound of 給水 (water supply) + 車 (vehicle).