Improvements on a system for treating residual water, presents a new solution for the conformation of a system for treating residual water and for such purpose, it basically consists of a lower blanket (1), preferably produced in PVC, and of a cover blanket (2), which is also preferably produced in PVC, in any color, which may be double-faced, including, in the present model still features a reactor (3), a deep chamber (4) and an anaerobic pond (5), and such elements may be excavated in the soil (S) or made of stonemasonry or any kind of suitable material for this purpose.