Hello, I went a few times to Huai Tung Thao Reservoir  few years back,  I don't recall if there was dual pricing at that time. 

 

Has anyone been there recently and might confirm the entry cost?    I read it might be 1000THB !   my old book says it was 20B

I think I paid 50 baht last time

 

The most enjoyable thing about this is arguing with the lady in the ticket booth while a long line of angry Thai drivers, who don't have to pay the same as you, wait behind you. Fortuitously, they have conveniently positioned a mom and pop shop near your stationary car so you can, in fact, pop out and get a beer or an ice cream while the lady with the ticket says 'mai dai' over and over again. It's the highlight of my family's day out.

50bht foreigner, 20bht Thai.