In Hai Phong, w'ater-quality monitoring has been conducted since 2006 in channels, lakes, estuaries and rivers of the Re River, Gia River and Da Do River. However, the number of parameters covered and the frequency is not sufficient, given the limited city budget (City of Hai Phong, 2015). In addition, to strengthen pollution source control with industry, the city should invest in installing real-time monitoring stations in major water systems and make the data available to the public. The sewer system of Hai Phong City, which is similar to other systems in urban areas across the country, is a tributary drainage system in which rainw'ater and w'astewater flow through the same system.