The eutrophication in the Baltic Sea is a big issue which threatens marine ecosystems, increases the depletion of oxygen in the water and causes harm to aquatic animals. Human activities such as industries, agriculture, forestry and untreated sewage increase nutrient input (mainly nitrogen and phosphorus) which causes increased levels of plankton and bacteria. Sweden has suggested to prohibit recreational craft owners to discharge their untreated wastewater to the ocean. The aim for this study is to examine and analyze the different types of water treatment systems that exist today and to see what levels of bacteria and nutrients the effluent water has from the systems. This research will help the EU-commission to decide what demands you can put on the discharged effluent water on recreational crafts. The study shows that none of the existing systems is able to decrease the levels of nutrients in the effluent treated wastewater. This makes it hard for the EU-commission to decide on demands for recreational crafts. This may lead to increased use of drainstations of wastewater in harbors for owners.