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Hong Kong Drinking Water Standards (HKDWS)

The Government currently adopts the corresponding guideline values/provisional guideline values in the fourth edition of the World Health Organization’s Guidelines for Drinking-water Quality (“WHO Guidelines”) published in 2011 as the Hong Kong Drinking Water Standards.

Parameter Unit HKDWS
Metals (12 parameters)
Antimony μg/L ≤ 20
Arsenic μg/L ≤ 10
Barium μg/L ≤ 700
Boron μg/L ≤ 2400
Cadmium μg/L ≤ 3
Chromium μg/L ≤ 50
Copper μg/L ≤ 2000
Lead μg/L ≤ 10
Mercury μg/L ≤6
Nickel μg/L ≤ 70
Selenium μg/L ≤ 40
Uranium μg/L ≤ 30
Pesticides (33 parameters)
Alachlor μg/L ≤ 20
Aldicarb μg/L ≤ 10
Aldrin and Dieldrin μg/L ≤ 0.03
Atrazine and its chloro-s-triazine metabolites μg/L ≤ 100
Carbofuran μg/L ≤ 7
Chlordane μg/L ≤ 0.2
Chlorotoluron μg/L ≤ 30
Chlorpyrifos μg/L ≤ 30
Cyanazine μg/L ≤ 0.6
2,4-D (or 2,4-dichlorophenoxyacetic acid) μg/L ≤ 30
2,4-DB (or 4-(2,4-dichlorophenoxy)butyric acid) μg/L ≤ 90
DDT and metabolites μg/L ≤ 1
1,2-Dibromo-3-chloropropane μg/L ≤ 1
1,2-Dibromoethane μg/L ≤ 0.4
1,2-Dichloropropane μg/L ≤ 40
1,3-Dichloropropene μg/L ≤ 20
Dichlorprop (or 2,4-DP) μg/L ≤ 100
Dimethoate μg/L ≤ 6
Endrin μg/L ≤ 0.6
Fenoprop (or 2,4,5-TP) μg/L ≤ 9
Hydroxyatrazine μg/L ≤ 200
Isoproturon μg/L ≤ 9
Lindane μg/L ≤ 2
MCPA (or (2-methyl-4-chlorophenoxy)acetic acid) μg/L ≤ 2
Mecoprop (or MCPP) μg/L ≤ 10
Methoxychlor μg/L ≤ 20
Metolachlor μg/L ≤ 10
Molinate μg/L ≤ 6
Pendimethalin μg/L ≤ 20
Simazine μg/L ≤ 2
2,4,5-T (or 2,4,5-trichlorophenoxy acetic acid) μg/L ≤ 9
Terbuthylazine μg/L ≤ 7
Trifluralin μg/L ≤ 20
Disinfectants (3 parameters)
Chlorine mg/L ≤ 5
Monochloramine mg/L ≤ 3
Sodium dichloroisocyanurate (as cyanuric acid) mg/L ≤ 40
Disinfection by-products (14 parameters)
Bromate μg/L ≤ 10
Bromodichloromethane μg/L ≤ 60
Bromoform μg/L ≤ 100
Chlorate μg/L ≤ 700
Chlorite μg/L ≤ 700
Chloroform μg/L ≤ 300
Dibromoacetonitrile μg/L ≤ 70
Dibromochloromethane μg/L ≤ 100
Dichloroacetate μg/L ≤ 50
Dichloroacetonitrile μg/L ≤ 20
Monochloroacetate μg/L ≤ 20
N-Nitrosodimethylamine μg/L ≤ 0.1
Trichloroacetate μg/L ≤ 200
2,4,6-Trichlorophenol μg/L ≤ 200
Other Inorganic Chemicals (3 parameters)
Fluoride  mg/L ≤ 1.5
Nitrate (as NO3-) mg/L ≤ 50
Nitrite (as NO2-) mg/L ≤ 3
Organic Chemicals (24 parameters)
Acrylamide μg/L ≤ 0.5
Benzene μg/L ≤ 10
Benzo(a)pyrene μg/L ≤ 0.7
Carbon tetrachloride μg/L ≤ 4
Di(2-ethylhexyl)phthalate μg/L ≤ 8
1,2-Dichlorobenzene μg/L ≤ 1000
1,4-Dichlorobenzene μg/L ≤ 300
1,2-Dichloroethane μg/L ≤ 30
1,2-Dichloroethene μg/L ≤ 50
Dichloromethane μg/L ≤ 20
1,4-Dioxane μg/L ≤ 50
Edetic acid (EDTA) μg/L ≤ 600
Epichlorohydrin μg/L ≤ 0.4
Ethylbenzene μg/L ≤ 300
Hexachlorobutadiene μg/L ≤ 0.6
Microcystin-LR (total) μg/L ≤ 1
Nitrilotriacetic acid μg/L ≤ 200
Pentachlorophenol μg/L ≤ 9
Styrene μg/L ≤ 20
Tetrachloroethene μg/L ≤ 40
Toluene μg/L ≤ 700
Trichloroethene μg/L ≤ 20
Vinyl chloride μg/L ≤ 0.3
Xylenes μg/L ≤ 500
Microbiological (1 parameter)
E. coli cfu/100 mL 0
Radiological (2 parameters)
Gross alpha activity Bq/L < 0.5
Gross beta activity Bq/L < 1.0