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.

New ruling probably apply to high end houses only next year. If all houses have to fix one, die-loh. Pump is not cheap. House prices already high enough to kill.

I plan to fix one in the back, water from gutter, rough filter, use small pump to set up automatic watering system for plants. Still planning stage.