You may have picked up on this already or, now that you’ve been made aware of it, you’ll notice it on your next visit to Spain. 

Some buildings or houses in Spain have two or even more bottles of water placed at the property’s entrance in the street, usually strategically positioned on either side of the main door on the pavement. It’s also not uncommon to see bottles of water placed outside small shops and businesses.

In case you were wondering, it has nothing to do with Spain being a relatively hot country – it’s no selfless offering of H20 to passers-by or a way to keep the ground cool. 

It’s such a quirky sight that in 2018 a Reddit user posted a photo of a row of 5-litre bottles of water lined up on a residential road, asking “Spain. Why are there water bottles outside all the driveways and entrances?”.

The general consensus among Spanish commentators on the thread and other Spanish sources is that the practice is all about stopping cats and dogs from urinating on people’s doorways. 

Some claim that with cats the habit stops them from doing their business as they don’t want to ‘pollute’ clean water with their urine. 

There are also those that claim it has something to do with dogs and cats seeing their reflection in the water and being put off from the toilet break.

According to local daily La Gaceta de Salamanca, leaving bottles on building corners and entrances replaced the more dangerous tradition of sprinkling lye or sulphur on the walls and ground of homes and businesses in the Castilian city, but this was a huge health hazard that’s now been banned. 

So does the water bottle solution work? Well, some swear by it while others see it more as an old wife’s tale.

“We do not know if it is effective, but it is true that dogs can be scared because they see themselves reflected or because the sun causes a reflection on the water and, just like pigeons, it bothers them and they get frightened”, President of the Salamanca veterinary college Antonio Rubio told La Gaceta.

Others aren’t so convinced: “No scientific study has been carried out to check if it works but we know that it is not effective,” Vigo veterinarian Xiana Costas told her local daily El Faro de Vigo in northwestern Spain. 

“Probably at first a dog is put off peeing by the obstacle of the bottle but a more daring pooch will mark its territory no matter what. But I’ve never seen a dog that’s scared of a bottle.”

It’s not known whether this practice originated in Spain or somewhere else, but leaving bottles of water outside doorways or even tied to trees in communal gardens is also reportedly done in Italy, Mexico, Colombia, Argentina and even Japan. 

In most of these countries street dogs and feral cats are blamed for pee stains left on walls and doorways, but in Spain it’s often dog owners who are held responsible for allowing their pets to mark their territory in the wrong place. 

If you are a dog owner in Spain the recommended thing to do is to spray their pee with water mixed with a bit of washing up liquid or vinegar.

Cleaning up these territorial markings is according to veterinarian Costas also the best way to prevent more pongy pee from appearing on walls and corners of Spanish buildings. 

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