On Thursday night of last week, my wife and I drove to Cambria, California to meet some long-time friends. The drive took about 4 hours. Our plan was to:

see the sea:

visit Hearst Castle:

taste wine at local wineries:

and just hang out with friends:

So we were prepared for those activities. What we were not prepared for was the severe water shortage that Cambria is facing. The situation is so dire that businesses posted signs that bathrooms were not available:

Even the splendid Hearst Castle had port-a-potties for visitor use instead of wasting water by flushing.

There were 6 of us staying at a rental house that was limited to 50 gallons per day. Placards pleading for water conservation were posted throughout the house:

We obliged by showering as quickly as possible every other day in groups of 3. We only flushed the toilets when really necessary (#2 versus #1).

Back here in the Bay Area we routinely conserve water but not in such drastic fashion. The Cambria experience made me consider how water flows in our own home.

Since salt water desalination is a technology whose day will not come for quite some time, perhaps homes should be plumbed as follows?

This plumbing configuration seems to make sense as the water that fills toilets does not have to be drinkable. The toilets can be filled from a reservoir that collects water when it goes down the drains from the other fixtures and appliances. Though this kind of plumbing may be more expensive, better use of home water is certainly preferable to the rationing we experienced in Cambria. Gray water is a generic term that describes water from showers, bathtubs, laundry, and bathroom sinks. Properly treated, this water can be recycled and reused for landscape irrigation and certainly, flushing toilets.

Maybe we could get even fancier and collect rainwater in addition to gray water?

Luckily I am not alone in my thinking.

Pondering water conservation is alive in the lab.