The Great Lotus catchment has a population of about 380 000 people. Approximately 24% reside in informal settlements, while 4% live in informal housing in the site and service areas. The informal population of the Greater Lotus River catchment is growing especially rapidly, due to its desirable location near to job opportunities, and large areas of "municipal open space". The Great Lotus River is characterized by poor water quality, with high nutrient loading, as well as very high faecal coliform counts. This is due to raw sewage effluent overflowing from blocked sewers into the storm water drains, occasional sewer pump overflows, as well as the inadequate or non-existent sanitation characteristic of the informal settlement areas. Despite recent efforts by the local authorities at sewer upgrading, the microbial counts in the storm water do not appear to be dropping.