The sewerage system in Iringa Municipality has a total length of 47.79 km and is relatively in good a condition. It covers the central business district area, serving 16% of total population. The main trunk sewer of the network (DN 300 Asbestos Cement) was constructed in year 2000. The lateral sewers comprise of different sizes of uPVC pipes that vary from DN 100 to DN 200. The trunk main of DN 300 is the sewer outfall, which joins the manholes to the wastewater treatment plant.

IRUWASA has waste stabilization ponds (WSPs). The WSPs are large, shallow basins in which raw sewage is treated entirely by natural processes involving both algae and bacteria (microorganisms). The plant has three units, namely; two anaerobic ponds in parallel, one facultative pond in series and two maturation ponds in series. Thereafter, the effluent from the maturation pond is discharged into two compartments of constructed wetlands for further treatment. The constructed wetlands are artificial wastewater treatment systems consisting of shallow (usually less than 1 m deep) ponds or channels in which aquatic plants have been planted. The treatment of the waste water in the shallow ponds relies on natural microbial, biological, physical and chemical processes.


IRUWASA owns two cesspit emptier trucks which collect domestic wastewater from septic tanks and pit latrines and subsequently transport the same to the sludge ponds for further biological treatment process in the Wastewater Stabilization Ponds (WSPs).


Wastewater quality monitoring is normally carried out several times a year. The parameters monitored are: Physical Analysis: PH, Conductivity, COD; Chemical Analysis: Ammonia, Total Dissolved Solids (TDS), Bacteriological Analysis; E-coli and BOD5.Generally the results from tests conducted do not meet the required effluent standards. In order to meet the required effluent standards IRUWASA is expanding the treatment plant by constructing 2 new maturation ponds. Additionally, IRUWASA has plans to introduce reagents for activating the microorganisms’ biological process in the wastewater stabilization ponds.


The gravity sewerage system in Iringa Municipality has a total length of 47.79 km. The sewerage services cover 16% of the total 151,345 inhabitants. The trunk sewer pipes are designed to handle about 3,746,000 liters of wastewater per day. The present treatment is at 4,320,000 liters per day and the total number of connections made is 1,975 as of December 2017 equivalents to 29,554 people. Iringa Municipal generates around 8,272,390 liters of wastewater per day.