WASH in Low income communities

Dhaka the capital city of Bangladesh has about more than 100 informal settlements having about 1,000,000 people ( estimated) taking water from Dhaka WASA system illegally mostly. Dhaka WASA following MDGs and now present SDGs trying to give legal water connections to them with the help of donors. Over the last  8 to 10 years it has given almost 6000 legal connections. The present operational model is called CBO (community-based organization), and there are local powers who are doing illegal business out of the water. What do you think about sustainable O & M model of WASH services in these low-income consumers?