Techonology that is expensive today will be much cheaper in 20 years. The first smart phones were too expensive for developing countries.

Economies and research of scale can make nanotech filters cheaper. The same goes for computer chips and sensors

Existing sink companies don't have the internal culture to produce high tech sinks that are actually good. It seems to need a different mindset.

Peter Thiel speaks a lot about how there little innovation in atoms over the last decades. There's room for innovation in the bathroom and the kitchen.

It's not only about saving water. If you get a sync to recycle water you can do things like automatically adding soap to the water when washing your hands.