Hi New2grammar and Khoff
When Singaporeans ask for water in a restaurant, they use the term pain water. Plain water may, nevertheless, have ice in it.
Standard English speakers would simply ask for water.
(Singapore English in a Nutshell by Adam Brown)
The author is an Associate Professor in the School of Arts of the National Institute of Education, Nanyang Technological University. He has taught at universities in Britain,Thailand and Malaysia. He holds a doctorate in phonetics frrom the University of Edinburgh, and has written widely on lingustics and English language teaching.