Fire water refers to water that has been used in fire fighting and requires disposal.
In many cases it is a highly polluting material and requires special care in its disposal

In many fire fighting situations, large quantities of water remain after the fire has been extinguished. The water contains materials present in the building and also contains dissolved and particulate materials from combustion processes and materials generated through quenching. Fire water can be particularly polluting when the building or site being extinguished itself contains potentially polluting materials such as pesticides, organic and inorganic chemical reagents, fertilizers, etc. Certain types of premises including farms and the chemical industry pose special risks because of the types of materials present. Premises containing quantities of plastics can also cause severe problems because of the taste and o dour imparted to the fire water. Releasing contaminated fire water into a river or other water source subsequently used to supply drinking water may render the untreated water supply unsuitable for drinking or food preparation.

Managing fire water frequently requires that the water be contained on site and then removed from site for specialized treatment. One of the recognized techniques is to contain the fire water in the drainage system using pneumatic bladders or lockable non-return valves which can be activated either automatically or manually