Different methods are being used for the removal of unwanted material from waste sewage water such as mini sewage treatment plant, infiltration and filter bed. But as compared to all above methods introduction of marsh is more beneficial, as marsh efficiency is much better then above mentioned methods. Marshes also have important role in biodiversity. Domestic waste sewage water contains organic material, viruses, bacteria and pathogens, nitrate and phosphate. These all factor influence the external environment. Removal of nitrate and phosphate is necessary because if they are not removed they may cause rapid increase in the growth of algae. Algae have short life span so they die. Bacteria use a lot of oxygen for the decomposition of algae. So as a result there becomes deoxygenating in the marsh. Most of the animals die because of lack of oxygen in the water source. Marsh method is better as compared to other methods for the removal of organic material and nutrients. Subsurface flow is needed in wetland for getting the best result. Subsurface flow wetland system will make the process better and it will minimize the effect of odor and insects and these both things directly create bad effect on external environment. In the subsurface flow wetland Phragmites australis and similar plants are used. Bacteria grow on the roots of these plants and break down the nutrients. Waste water treatment marshes are best suited for smaller towns, villages and single family homes. They work best under relatively warm conditions, but many are used in temperate climate as well. For the removal of microorganisms, chlorine is to be used, as it is best way for the removal of it. A de-chlorination process is also necessary, otherwise this water will create bad effect on aquatic life.