When a property is registered a plan is submitted the size comes from this.How is the sqm of the built up property assessed?
I have not heard of an extra tax for a pool but anything is possible. If the house plan includes a pool then I guess they use that.
Cannot see where a pool tax comes from and as Crazy88 points out what is the difference between a large pond that is used for swimming and a pool?
Ask a lawyer and get an answer if you do not like the answer ask another lawyer who will give you another
How can Thai lawyers ever maintain face unless they just make things up when they do not know the answer.For sure if they are like the Thais I have asked directions from they will never say 'I do not know'