Utilities make up a dependable expense in a family's budget. Along with grocery expenses, it's also a place that usually has a bit of slop that can be removed if things get tight.
And if cleanliness is next to godliness, certainly we all take regular showers or baths. The extent to which we do this directly affects our utility bills.
A typical shower or bath consumes on the order of 30 to 40 gallons of water. It's easy to estimate this:
- Start filling the tub. Note the time.
- Grab a pitcher — we used a gallon pitcher — and measure how long it takes to fill the picther. Ours took 20 seconds to fill. This is three gallons per minute (one gallon divided by one-third of a minute).
- When the tub is done filling for your bath, turn the water off and note the time. It took us 12 minutes to fill the tub to the proper level.
- Running the faucet at three gallons per minute for 12 minutes puts out a total of 36 gallons. Done.
You can figure out the amount of water used in a shower the same way.
This water goes down the drain. Now, of course, it's greywater (household wastewater), so it has more limited use.
But it's not useless. If you can tolerate keeping the tub full after taking a bath or shower, this greywater in most cases can be re-used to flush toilets. All you need is a couple of pitchers.
Flushing the toilet with greywater from the bathtub, then, involves repeating these steps:
- Pour about a gallon of water into the bowl quickly. If you can get by with less, great. This will flush the bowl and leave the water level low in the bowl.
- Pour one to two quarts of water slowly into the bowl to refill the bowl.
Note: Don't fill the toilet holding tank with the greywater. This can be hard on the flushing mechanisms, and might back-siphon into the fresh water supply if the water pressure drops. Pour the water directly into the bowl. (It will take the same path that all greywater would go.)
This might fall into the “more trouble than it's worth” category, but we've already re-used a tub's worth of water by doing this. We personally haven't seen any ill effects with the tub water hanging around for a few days, but one to two tablespoons of chlorine bleach per gallon would knock most of the nasties out of the water. It's an individual judgment of risk and trouble vs. reward. Even a few gallons saved is better than nothing.
If this is indeed more trouble than it's worth, then what about just capturing the water coming from the shower head as it's heating up? I get a gallon of water right there, and it's clean water, not greywater.
Anyone have more elaborate greywater systems (especially installed ones)?
In theory it’s a great idea but as you point out, it’s pretty hard to make work for a long term basis. I think focusing on lower length showers and efficient shower heads that reduce water flow but still give you a strong feeling flow are things that will add up to greater savings. The ideas you mention, while great, will be fleeting for most people as they’ll probably quit doing those things after a couple of tries.
The problem I’d have is the slow leak of my tub drain. It doesn’t hold water properly. I’d have to get another cover for the drain, but that’s pretty inexpensive. I just wonder the feasibility for large vs. small families. It would be easier for a couple or smaller family to leave the tub filled, but it wouldn’t save them as much money (by the time shower time rolls around again and the water still there needs to be drained anyway).
Interesting. Our water costs $4 per 1000 gallons, and our last quarterly bill was $80, so we used about 20,000 gallons. I suspect a large volume of water is for washing, both clothes and the dishwasher.
I think in an area where water is really scarce this may be a practical idea. If water is that precious, letting any go literally down the drain is a sin. Our main shower has no tub, it’s a walk-in, so no way to save the water. I’ll admit that during the summer when we’re watering the lawn, I wish I could divert the waste shower water out to the lawn instead of confining it to the septic.
We used to use this exact method quite a bit when I was a kid. My mom was pretty frugal and did not want to waste any water. We used to have some water shortages in the peak of the summer, so I think some of it probably was out of her habits.
I think it is still a good idea, thanks for posting on this. Clean water is a pretty scarce resource in a lot of parts of the world and will only become more scarce.