War water is water in which iron has stood - nails, rusted iron, sometimes a piece of the war water 'mother' that a supplier sells - and it is the tradition's aggressive protective: it is put down at a door to keep harm out and, in its hostile use, thrown at a doorstep or a car to bring trouble to an enemy. The logic is the logic of iron and rust, of the blade and the blood, and it belongs to the same family of ideas as the horseshoe nailed above a door. Long records it as one of the standard bottled goods of the trade, sold with a printed instruction sheet that the tradition itself never had.
It is poured in a line across a threshold, at the four corners of a property, or against the door of an enemy; it is added to a wash or used to 'dress' a step. In some accounts the bottle is shaken first and the water is not allowed to become clear. It rusts and stains whatever it touches, which is part of the effect and part of the problem.
War water has an openly aggressive use, and the tradition names it honestly: it is not a barrier like brick dust but a declaration. Pouring it at someone else's door is an attack, it damages property, and it is the kind of work the tradition's own ethic requires to be justified. The water itself is a biological and chemical hazard - rust, soil and standing water - and it should not be handled or kept where children can reach it.
Every entry that names War Water, grouped by the system it comes from.