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International Comparison of Water Quality

Comparison of TWD's Tap Water Quality with U.S., Japan, E.U., W.H.O.'s Guidelines, and Water Quality Standards of EPA, R.O.C.

Microbial Parameters
Parameters	TWD Tap Water Quality	Maximum Contaminant Level
Parameters	TWD Tap Water Quality	Taiwan (2020)	U.S. (2018)	Japan (2015)	E.U. (2015)	W.H.O. (2017)
1.Total Coliforms (CFU/100ml,MPN/100ml)	<1	6	5.0% ^＊1*2	0^*3	0	0
2.Total Bacterial Count (CFU/ml)	1	100	-	100	^*4 (22˚C)	0

Unit : mg/L (unless specified otherwise)
Maximum Contaminant Level Goal（MCLG）：The level of a contaminant in drinking water below which there is no known or expected risk to health. MCLGs allow for a margin of safety and are non-enforceable public health goals.
*1.No more than 5.0% samples total coliform-positive in a month. (For water systems that collect fewer than 40 routine samples per month, no more than one sample can be total coliform-positive per month.)
*2. Fecal coliform and E. coli are bacteria whose presence indicates that the water may be contaminated with human or animals wastes.
*3. Drinking water standard of Japan set E-coli only.
*4. Acceptable to consumers and no abnormal change.

Physical Parameters
Parameters	TWD Tap Water Quality	Maximum Contaminant Level
Parameters	TWD Tap Water Quality	Taiwan (2019)	U.S. (2018)	Japan (2015)	E.U. (2015)	W.H.O. (2017)
1.Odor (TON)	2	3	3^＊5	^*4	^*4	^*4
2.Turbidity (NTU)	0.10	2	TT^＊6	2	^*4	-
3.Color (Pt-Co units)	2	5	15^＊5	5	^*4	-

Unit : mg/L (unless specified otherwise)
NTU = nephelometric turbidity unit.
*5. National Secondary Drinking Water Regulations (NSDWRs or secondary standards)
*6. TT :Treatment technique required

Chemical Parameters
Parameters	TWD Tap Water Quality	Maximum Contaminant Level
Parameters	TWD Tap Water Quality	Taiwan (2019)	U.S. (2018)	Japan (2015)	E.U. (2015)	W.H.O. (2017)
(A) Substances affecting health
1. Arsenic (As)	ND （< 0.0012）	0.01	0.01	0.01	0.01	0.01
2. Lead (Pb)	ND （< 0.0007）	0.01	0.015^＊7	0.01	0.01	0.01
3. Selenium (Se)	ND （< 0.0010）	0.01	0.05	0.01	0.01	0.04
4. Chromium (Cr)	ND （< 0.0004）	0.05	0.1	0.05 (Cr⁶⁺)	0.05	0.05
5. Cadmium (Cd)	ND （<0.0005）	0.005	0.005	0.003	0.005	0.003
6. Barium (Ba)	0.006	2.0	2.0	-	-	0.7
7. Antimony (Sb)	ND （<0.0004）	0.01	0.006	-	0.005	0.02
8. Nickle (Ni)	ND （< 0.0003）	0.02	-	-	0.02	0.07
9. Mercury (Hg)	ND （< 0.00004）	0.001	0.002	0.0005	0.001	0.006
10.Cyanide (CN-)	ND （< 0.003）	0.05	0.2	0.01	0.05	-
11.NO- 2-N (Nitrite Nitrogen, as N)	ND （< 0.0004）	0.1	1	0.04	0.1	3
Disinfection by-product
12.Trihalomethanes (THMs)	0.00607	0.08	0.08	0.1	0.1	*8
13. Haloacetic acids (sum of concentrations of Monochloroacetic acid(MCAA), Dichloroacetic acid, Trichloroacetic acid(DCAA), Monobromoacetic acid(MBAA) & Dibromoacetic acid(DBAA))	0.0138	0.060	0.06	0.02 (MCAA) 0.03(DCAA) 0.03(TCAA)	-	0.02(MCAA) 0.05(DCAA) 0.2(TCAA)
14. Bromate	ND （<0.0007）	0.01	0.01	0.01	0.01	0.01
15. Chlorite	ND （<0.02）	0.7	1	-	-	0.7
Volatile Organics
16.Trichloroethylene	ND （<0.00045）	0.005	0.005	0.01	^*10	0.02
17.Carbon Tetrachloride	ND （<0.00048）	0.005	0.005	0.002	-	0.004
18.1,1,1-Trichloroethane	ND （<0.00048）	0.20	0.20	-	-	-
19.1,2-Dichloroethane	ND （<0.00048）	0.005	0.005	-	0.003	0.03
20.Vinyl chloride	ND （<0.0004）	0.0003	0.002	-	0.0005	0.0003
21.Benzene	ND （<0.00047）	0.005	0.005	0.01	0.001	0.01
22.Para-Dichlorlbenzene	ND （<0.00045）	0.075	0.075	-	-	0.3
23.1,1-Dichloroethene	ND （<0.0005）	0.007	0.007	-	-	-
24. Dichloromethane	ND (<0.00054)	0.02	0.005	0.02	-	0.02
25. 1,2-Dichlorobenzene	ND (<0.00047)	0.6	0.6	-	-	1
26. Toluene	ND (<0.00046)	0.7	1	-	-	0.7
27. Xylenes	ND (<0.00068)	0.5	10	-	-	0.5
28. cis-1,2-Dichloroethene	ND (<0.00048)	0.07	0.07	0.04^*9	-	0.05^*9
29. trans-1,2-Dichloroethene	ND (<0.00044)	0.1	0.1	0.04^*9	-	0.05^*9
30. Tetrachloroethene	ND (<0.00046)	0.005	0.005	0.01	^*10	0.04
Pesiticides
31.Endosulfan	ND （<0.0000062）	0.003	-	0.01	^*12	-
32.Lindane	ND （<0.000003）	0.0002	0.0002	-	^*12	0.002
33.Butachlor	ND （<0.000062）	0.02	-	0.03	^*12	-
34.2.4-Dichlorophenoxyacetic acid	ND （<0.000015）	0.07	0.07	0.02	^*12	0.03
35.Paraquat^*11	ND （<0.00278）	0.01	-	0.005	^*12	-
36.Methomyl	ND （<0.000195）	0.01	-	0.03	^*12	-
37.Carbofuran	ND （<0.000185）	0.02	0.04	0.005	^*12	0.007
38.Isoprocarb	ND （<0.000171）	0.02	-	0.01	^*12	-
39.Methamidophos	ND （<0.000010）	0.02	-	-	^*12	-
40.Diazinon	ND （<0.000023）	0.005	-	0.003	^*12	-
41.Parathion	ND （<0.000066）	0.02	-	-	^*12	-
42.EPN	ND （<0.000068）	0.005	-	0.004	^*12	-
43.Monocrotoohos	ND （<0.000036)	0.003	-	-	^*12	-
Persistent organic pollutants, POPs
44. Dioxin (pg WHO-TEQ/L)	0.004	3	3	30^*13	-	-
(B) Substances probably affecting health
1.Fluoride (F-)	0.07	0.8	4.0^*14	0.8	1.5	1.5
2.NO3-N (Nitrate Nitrogen ,As N)	0.48	10.0	10.0	10	50	50
3.Silver (Ag)	ND （<0.0006）	0.05	0.1^*5	-	-	-
(C)Substances affecting palatability
1.Iron (Fe)	ND （<0.0014）	0.3	0.3^*5	0.3	0.2	-
2.Manganese (Mn)	ND （<0.0005）	0.05	0.05^*5	0.05	0.05	-
3.Copper (Cu)	ND （<0.0006）	1.0	1.0^5 1.3^7	1.0	2.0	2.0
4.Zinc (Zn)	ND （<0.0007）	5.0	5.0^*5	1.0	-	-
5.Sulfate (SO4-2)	11.0	250	250^*5	-	250	-
6.Phenols	ND （<0.0009)	0.001	-	0.005	-	-
7.MBAS (Anionic Surfactant, Methylene Blue Activated Substance)	ND （<0.03）	0.5	-	0.2	-	-
8.Chloride (Cl-)	5.2	250	250^*5	200	250	-
9.NH3-N (Ammonia Nitrogen, As N)	ND （<0.011）	0.1	-	-	0.5	-
10.Total Hardness*14, as CaCO3	30.8	300	-	300	-	-
11.Total Dissolved Solids	58	500	500^*5	500	-	-
12. Aluminum (Total Al)	0.059	0.2	0.05~0.2^*5	0.2	0.2	-
D. Residual chlorine	0.57	0.2~1.0	4	-	-	0.2-5.0
E. pH value	7.2	6.0~8.5	6.5~8.5 ^*5	5.8~8.6	6.5~9.5	-

ND : Non detected.
Unit : mg/l (unless specified otherwise)
*7. Lead and copper are regulated by a Treatment Technique that requires systems to control the corrosiveness of their water. If more than 10% of tap water samples exceed the action level, water systems must take additional steps. For copper, the action level is 1.3 mg/L, and for lead is 0.015 mg/L.
*8. The sum of the ratio of the concentration of each to its respective quideline value should not exceed 1.
*9. The sum of concentration of cis-1,2-Dichloroethene and trans-1,2-Dichloroethene should not exceed 0.04 mg/L in Japan, and WHO set should not exceed 0.05 mg/L.
*10. Sum of concentrations of Tetrachloroehtene and Trichloroethene should not exceed 0.01 mg/L.
*11. paraquat (as dichloride), quivalent to 0.007 mg/L for paraquat ion.
*12. Pesticides,each 0.0001 mg/L ,Total: 0.0005 mg/L.
*13. USEPA set the 2,3,7,8-TCDD(Dioxin) as 3x10^-8 mg/L.
*14. USEPA also set the SMCL(Secondary Maximum Contaminant Limits)as 2 mg /L for fluoride Public acceptance of hardness varies considerably.
*15. The limt value of pesticide in Japan is the target for water quality management in 2019
*16. Generally, hardness levels between 80 and 100 mg/L (as CaCO3 ) are considered acceptable; levels greater than 200 mg/L are considered poor but can be tolerated; those in excess of 500 mg/L are normally considered unacceptable.

Taipei Water Department

International Comparison of Water Quality

Microbial Parameters

Physical Parameters

Chemical Parameters

(A) Substances affecting health

(B) Substances probably affecting health

(C)Substances affecting palatability

D. Residual chlorine

E. pH value