The environmental study of the sewerage systemof the San Andres lsland Realized by the groupTecnoambiental conducted in 2007, covers the northof the lsland. it was determined that it presentsproblems in the networks by the topographicalconditions. which were conducted by reviewing thefe atures hydraul ic system as shear, minimum speedand depth of the pipeline among others; whose rankswere compared with those set out in the TechnicalRegulations Sectors drinking water and basicsanitation - RAS 2000.Likewise assessed the impacts to the environmentgenerated by the disposal of waste water whichis discharged into the sea without prior treatmentthrough the undersea outlet, for that reason were arepredesigned units Plant Wastewater Treatrnent whichto be implemented will decrease the impacts to anecosystem as fragile as the one presented at sea.