What is the main determinant cause of Singapore success? Water?

https://sg.news.yahoo.com/mahathir-believes-singapore-rapidly-developed-030901104.html

Mahathir believes that the main determinant cause of Singapore success is water.

However, Malaysia has more water than Singapore.  How come Malaysia is not as successful as Singapore when it has more water resources?  The exchange rate for MY:SG should be 1:3, not 3:1 if Mahathir is right about SG's success.