The tendinitis in my shoulder is keeping me from much progress on the house, or from doing a lot of things like driving without some pain and further damage involved. So I've been researching various things for the house on the web. There are so many great ways to save energy and water that it's all kind of dizzying. The cats are happier when I'm sitting at the computer than making construction noise, so they like the research, too.
Given that California frequently has droughts, and by nature has dry summers, saving water makes a lot of sense. Of course, what we could save is a drop in the bucket (hah!) compared with gets used for commercial and agricultural uses. And agricultural uses are a drop in the bucket compared with what gets used for raising and processing meat, which is particularly water-intensive (especially when 143 million pounds of it has to be disposed of -- ugh!). But it still makes sense to save what we can.
Some ways of saving water are too simple to pass up, like rain barrels (unless you live in Colorado, where collecting rainwater is illegal.) For less than $50 you can get a food-grade barrel and some fittings, and collect 55 gallons of rainwater, perfect for watering plants and gardens. We've got 7 downspouts around the house, plus one from the roof of the carport, so we could easily collect more water than we could use (at least until we plant a garden again or actually take care of the plants in the yard.) I'm envisioning a system of two or three barrels, with pipes draining them leading to a spigot in the back of the house near the current hose spigot. It's low enough that gravity would give it a pretty decent flow, and be near the backyard where most of our watering needs are.
At the other end of the complexity scale is adding a graywater system to collect the water from bathroom sinks, showers, and the laundry, then using that water to irrigate or for flushing toilets. It would involve not only a storage tank with a way to deal with overflow, but a pump to drive the system, and a way of using EBMUD water if the storage tank is empty. It would basically be a second DWV system, plus parts of a second water supply system to go to the toilets. A lot of work for limited payback, and it's not legal in all areas.
Another fairly simple way is a hot water recirculation system. You've doubtless left the shower or a sink running to let the water get warm, and all that nice, drinkable water just goes down the drain. Hot water recirculation systems get water from the hot side, and if it's not warm enough yet, push it back down the cold side (a more complicated but more efficient variation uses a separate return line.) Some systems keep hot water circulating all the time, so it's available "instantly". That would waste energy keeping water hot whether you're using it or not, not to mention add unnecessary wear and tear to the water heater. And without a dedicated hot water return, it would make all your cold water lukewarm. Other systems like the RedyTemp or the Metlund D'MAND are timer, motion or demand-activated.
Our hot water use doesn't follow any set schedule, so we'd go for a demand-activated system: you push a button, wait a couple minutes, and voilà, there's hot water a couple of feet down the pipe instead of waiting for the water to flow, the tankless heater to kick in, and then for the cold water to be flushed from the system. Those systems and others are very easy retrofits if you've got an outlet near the fixture furthest from the water heater. Since I had a hot water recirculation system in mind, I didn't go as far as plumbing a dedicated return line, but I did stick a GFCI outlet in the vanity in the new bathroom.
Now the only problem is figuring out which is the right system for us. Tankless water heater manufacturers will reduce the warranty if you use the wrong recirculation system, because very high flow rates can erode pipes and fittings and put additional wear and tear on a water heater. Anybody out there in readerland have personal experience with one of these systems, with or without a tankless heater?