A specific environmental problem is water in brownfields that are or may be contaminated by dangerous substances. Until now, little attention has been devoted to this issue, especially as regards the current modern approach in the area of so called integrated water management in brownfields. It should be stressed that these localities are abandoned and not maintained, usually with combined contamination, which makes them difficult to use. They can be both small and large, both rural and urban. Contaminated water can be in various forms, eg in lagoons, in sub-surface and surface reservoirs, ponds, etc. Occasionally, there can be located variable productions with variable capacities, which can still produce contaminated wastewater.