Saving Warmup Water

A Spanish company is implementing an invention that has occurred to me over the years; is there a way to capture water that is wasted between the time someone turns on the hot water and when that water actually gets hot. During that time the perfectly good, treated water runs down the drain. The invention is called the Water Drop by the Spanish company esferic. The device is a bag that is attached to a shower hose or the sink faucet to collect that wasted water. A more elaborate  option have a switch that would divert that water to an outdoor collection system through additional plumbing, a much more expensive method.

Waterdrop bag