It is a myth, based on last century facts, that sorting out existing water supplies and waste water management requires large amounts of capital (although good administration is very necessary).  
Modern electronics, costing less than 10 smartphones, can trace leaks in water mains and sub-mains.  Indeed some send details of the leaks to smartphones...
Then a new digger, costing the same as a new car, or a second-hand digger costing the same as a second-had car, a digger operator, and one or two chaps with shovels, spanners, saws, glue, sand, and a bit of savvy can cut out the leaky pipe and put a new one in.  These days it does not have to be iron pipe for the mains, plastic, glass fibre or carbon fibre if you are being fancy, do better, being more flexible.  There are plenty of connection systems to join the new to the old.
Hardly operations requiring "large amounts of capital."  It does need political will though.