One of the biggest resource wastes that we are often exposed to is running (and unused) water – straight from tap to drain. For example, we might be waiting for the shower water to flush the cold water that has been sitting in the pipes and the shower water to warm up. We might be brushing our teeth and not turning off the tap. What can you design to make use of this water? Yes, there are already recirculation systems that use the wasted heat (eg, radiant floor heating) or hot water recirculation systems that keep warm water near the point of use. Tankless water heater systems that are placed near the point of use can also address this issue.
But there is still an opportunity to collect the wasted water and use it efficiently by leveraging ease of use. For example, we could challenge ourselves to design a budget collection system that could be used to water the garden/house plants or wash the floor or rinse the shower door after use (control soap scum deposits).