Some houses near where I live (in CM) have a row of plastic bottles filled with water lined up in front of their garden fence, on the outside.

What is the purpose of this? I'm thinking to repel evil spirits or something?

Some people think it keeps dogs away from their place and dropping their 'business' there.

non-Parking place markers ...

guy near us puts plastic bottles beside his beautiful 21in mag wheels.I think its supposed to deter dogs ?

Stops dogs marking the area

There are several reasons a common one is used to keep the "good' spirits" of a house happy thus keeping 'evil" spirits away. Sometimes you may see red colored water as this is a very common drink (usually red fanta) that is supposedly enjoyed by the spirit ghost. Less of a true belief these days mostly done based on old traditions but still followed.

not in this case

Stops dogs marking the area

Especially the ones that have rabies (hydrophobia)

Put some out yourself and then they will think that you really have Thainess.

I have also seen this where I live in Buriram and also wondered why!!!!!!!

Also on balconies to scare off pigeons. Distorts images as the bottle acts as a lens scaring off dogs, cats, pigeons etc. (I think).

I leave empty beer bottles around my house to mark my territory.

As mentioned, used to keep dogs away. Often see them next to the wheels of vehicles parked on the street to keep the dogs from pissing on them. Apparently it is the distorted reflection of them in the water that does it.

Stops dogs marking the area so say

many dogs are like mine, anything plastic = place to wee...

LOL... yes, it's to stop dogs lifting their leg on the owners wall.

My neighbours do it. My dog is partially sighted and usually knocks the bottles over while sniffing along the wall. Then he pisses on the bottles.

I leave bottles of water in my fridge instead of beer to scare off unwanted guests.

I leave bottles of water in my fridge instead of beer to scare off unwanted guests.

Dangerous move. You might be tempted to drink it.

does it keep the dogs away?

just asked the Big Boss and her friends all eating Papaya pock pock for the new year and they say that the bottled water thing only works keeping cats at away!

Well that's one Thai mystery solved, thanks all.

Personally I think it looks terrible, really messy and untidy. I'd rather pick up dog poop from outside my house than have it surrounded by plastic bottles.