The later phases of Denai Alam by Sime Darby has rainwater harvesting system built-in by the developer.

Can read the owners' feedback on that thread.

Also thinking of doing it in my new house.

I've actually been asking around about a rainwater harvesting system. This is a reasonably new corner house. My main objective is not to save money but to have backup water supply when the mains go out, planned or unplanned.

It looks like there are two issues that usually come up. First is obviously cost, the people doing it out there will happily sell you at inflated prices, insisting you buy a pump for example when you don't even want one.

Second is the design of the house itself. My house for example has rain gutters coming down from all four corners of the roof, making it a bit more complex to reroute the water. The location of the tank itself is also a question, it's physically large (750l) and it's unclear how I can put the tank on the upper floor of my house when fully filled, the tank will weigh close to 800kg!

So as of now I'm not sure what I want to do yet. Will have to go visit the different showrooms to find out what I can get for my money first...

I know rainwater cannot be used for drinking or cooking. I can buy drinking/cooking water in bulk, however I cannot (or would not) buy the same for flushing toilets or washing bathrooms for example which is equally important.

I'm quite worried about the ugly structure as well, which is why I'm still unsure about this setup now....

With all the current water shortages, I guess it will be a wise decision getting your own water supply, at least to flush the toilets.