 According to Orlando and Arias, there is not a national water quality inventory but rather regional and sporadic studies.For instance the National Planning Division, in a study of 1989 and 1993, estimated that the level of organic material discharged in Colombian water resources is 9,000 BOD per day, of which 4,000 are discharged solely by the agricultural sector.Water supply and sanitation in Colombia has been improved in many ways over the past decades.