If you have a cat or a dog, perhaps you've wondered why they seem to prefer the water in your toilet to the water in their water-dish. Political statement on your water quality, you think? A preference for strongly scented drinking materials? Actually, none of these.
See, I'm pretty sure you don't change the pet's water dish until it's empty, but you flush the toilet on a regular basis. This means the water in the toilet is fresh and cold, like a running river, and the dish gets tepid and stale, like a stagnant pond. Running river water is cool and nice, stagnant ponds are associated in your pet's instincts with disease.
Also, you have to water your lawn or garden, and it's a pain.
So I got an idea to kill two birds with one stone as it were. The pet's water dish is connected to two pipes. One pipe drains the unconsumed water to water your lawn. The other refills from your municipal water supply. The pet likes it, as it reminds the instincts of a running river, and your lawn likes it, because it gets water on a regular basis. And you like it, because you don't have to bother with moving the sprinklers around, yet again. The grass doesn't mind that the water is a little stale, because, hey, free water.
Or, instead of timing, it could be set to be reset by pet. The pet would press a button, flushing the old water out to the grass and producing new water. Lap lap lap lap.
Oh, and for efficiency's sake, the grass watering part should be below ground, trickling up. Less water lost to evaporation that way.