According to WHO it is 500 ...
Published by Mir Sarfaraz Ali Khan
According to WHO it is 500 ppm if I remember correctly.
Sarfaraz
2 Comments
We also adhere to the 500 ppm upper limit. www.adedgetech.com
Published by Ronit Erlitzki
That is for drinking water, not raw water.
Published by Joseph Cotruvo, President at Joseph Cotruvo & Associates, Water , Environment and Public Health