What’s in Concrete Washout Water?

Concrete itself, once hardened, is inert and harmless to the environment. However, we know that concrete or cementitious washout wastewater containing mortar, grout, plaster, stucco, or cement is caustic and considered to be corrosive with a pH over 12. Concrete washout has a toxicity level greater than ammonia and near the same pH level as pouring Drano into a storm drain. Washout of concrete equipment must be done with careful regard to its impact on the environment. The wastes from concrete washout can harm the environment if allowed to runoff from construction sites. As populations have grown and construction has expanded into new areas, building sites without proper concrete waste disposal have become a significant environmental concern.