Anne and I arrived in Jakarta, and it was raining. And it rained every day that we were there. It's clear that Jakarta (and most of Indonesia) does not have a water shortage problem.
What they do have is a water sanitation problem, as in open sewers everywhere and tap water that you cannot drink.
These problems are related, of course, since sewage will leak into groundwater (and perhaps piped treated water), making it unsafe to drink.
And then there's the smell. if you can imagine an entire city that smells like an overflowing, rancid toilet, then you can imagine what Jakarta smells like. Although I am sure that rats and other vermin like that situation, I am also sure that people do not.
Although it's probably not fair to criticize or draw conclusions on a few days' observation, I'd wager that local water and sanitation managers suffer from shortages of cash (unpaid bills or underbilling), effort (monopolistic bureaucracy) and/or ethics (corruption is BIG in Indonesia). These aspects, in some combination, probably explain why the water is not drinkable and the sewage is not treated properly.
Oh, and all those plastic water bottles floating around? Just charge a $0.02 tax and give $0.01 for each that is turned in. There are plenty of poor people to pick up all the bottles...
On a non-water related note, I'll also mention that Jakarta has terrible air quality. My eyes were watering and I had a headache after a few hours of walking around town. Of course, local residents do not walk that often, but their actions are more like the problem than the solution -- traffic in Jakarta is terribly congested. There are so many cars, motos and tri-wheelers struggling to get around that they move at an average speed that I could usually beat by walking.
As any economist will tell you, the solution to congestion is to raise prices -- via tolls on access to central Jakarta, for example -- but an easy first step would be to ban the use of tri-wheeler Bajaj scooters. These Indian machines have two-stroke engines and no sign of pollution control. Each one, I'd bet, puts out the pollution of 10 cars. If they were banned, people could still get around with taxis, buses, cycle-rickshaws, etc.
Bottom Line: Big cities in developing countries often have inadequate infrastructure, and Jakarta's is probably responsible for the premature deaths of many people.