It is an increasingly common sight in gardens, entrances and sidewalks: a transparent plastic bottle full of water, resting on the ground or hanging near the door. Far from being carelessness, it is a home trick that thousands of people use for a very specific purpose.
What the water bottle trick is for
The most widespread use of this trick is to keep dogs and cats away, both strays and neighbors’ pets, to prevent them from approaching the entrance, garden, or sidewalk of the house. The idea is to discourage animals from urinating, defecating, or digging in those spaces, a common problem in residential areas.
Many people place it at the garden gate, in flowerbeds, next to plants, or in corners where animals usually stop. Its popularity is due to the fact that it is a cheap, simple, and chemical-free method: it only requires a transparent bottle and water.
Why thousands use it in their homes
According to popular belief, the secret lies in the light and reflection. The bottle full of water acts like a kind of lens: it refracts sunlight and creates moving flashes and reflections that would be annoying or disconcerting for animals.
In the case of cats, it is believed that the reflections and refraction of light make them uncomfortable and keep them at a distance. For dogs, another theory is added: when they see their own distorted reflection or the flashes, they would become disoriented and prefer to avoid the area.
Some versions of the trick suggest that the effect is stronger if several bottles are placed or if a little bleach or vinegar is added, whose smell is also unpleasant for animals.