Nobody seems to know. My theory is that it creates lines of force that disturbs animals. I can measure the lines of force with my coat hanger divini...
In the neighborhoods of South Los Angeles and East Los Angeles there are bottles of water on the lawns. The bottles keep dogs and cats from pooping on the lawn. During the 70's I worked a lot in Venice California. At the time there was unenforced dog leash laws. I always bought smooth sole shoes, because every once in awhile I would accidentally stepped on the stuff. In areas with lots of dogs, there was lots of bottles of water, also lots of roofs of cars were dented from kids escaping from the dogs.
Step 1: Just start with 4 bottles
I got 3 bottles and one plastic container. 3 are Costco 1 gallon and the 4th is a plastic Lychee Nut Jelly container. Just fill them up with plain old water. The cap just keep it from spilling.
You don't need any additive in the water.