- Watering. In addition to a small yard, I have lots of tropical plants. Banana trees are thirsty creatures.
- Car Washing. I was my car by hand, about once per week.
- Cleaning other random things, such as my lawn mower, the shovel, and my patio.
Savings: $1.50 per month.
Math: My rain barrel holds 50 gallons, and I easily empty it four times a month on these activities. Where I live, 1 gallon of water costs about .75 cents. 200 gallons * .75 cents = $1.50 per month.
Return on Investment: In just over 5 years I will have saved enough water to pay for the rain barrel. This might be a stretch for some people. I listed two reasons when I justified the purchase: 1) it would feel good to do my part to conserve while getting a little something for myself (lower water bills); and 2) I had a large credit on my Amazon account from various gift certificates I had received, so my real cost was the opportunity cost of not spending that money on something different.