The construction of the drainage system of Tbilisi started in 1835. Generally they used brick sewers in which utility and sanitary waters as well as rainfalls flowed and empted in the river Mtkvari.
At present Tbilisi drainage systems with the diameter of 150- 1200 mm are built with brick, arch, concrete, reinforced concrete, ceramic, cast iron, asbestos cement and polyethylene pipes. The drainage system is self-flowing.
The total length of the system is 1600 km:
• 1000 km - street network
• 600 km – interquartile and yard network
The length of the main trunk sewer is 72 km. The waste waters run through the sewer to Gardabani Treatment Plant. There are 42 separating chambers on the main sewer.
There are 5 aqueducts on the River Mtkvari – Avchala, Didube, Metekhi, River Gldanula and River Digmuli.
The capacity of Gardabani Treatment Plant is 1, 0 million cubic meters/day.