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.
| Parameters | TWD Tap Water Quality | Taiwan (2022) | U.S. (2018) | Japan (2022) | E.U. (2020) | W.H.O. (2022) |
|---|---|---|---|---|---|---|
1.Total Coliforms (CFU/100ml,MPN/100ml) | <1 | 6 | 5.0%＊1*2 MCLG=0 | -*3 | 0 | -*3 |
2.Total Bacterial Count (CFU/ml) | <1 | 100 | MCLG=0 | 100 | *4 | - |
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 and W.H.O. set E-coli are non detected.
*4. Acceptable to consumers and no abnormal change.
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 and W.H.O. set E-coli are non detected.
*4. Acceptable to consumers and no abnormal change.
| Parameters | TWD Tap Water Quality | Taiwan (2022) | U.S. (2018) | Japan (2022) | E.U. (2020) | W.H.O. (2022) |
|---|---|---|---|---|---|---|
1.Odor (TON) | 1 | 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
NTU = nephelometric turbidity unit.
*5. National Secondary Drinking Water Regulations (NSDWRs or secondary standards)
*6. TT :Treatment technique required
(A) Substances affecting health
| Parameters | TWD Tap Water Quality | Taiwan (2022) | U.S. (2018) | Japan (2022) | E.U. (2020) | W.H.O. (2022) |
|---|---|---|---|---|---|---|
1. Arsenic (As) | ND （< 0.0017） | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 |
2. Lead (Pb) | ND （< 0.0011） | 0.01 | 0.015＊7 | 0.01 | 0.005 | 0.01 |
3. Selenium (Se) | ND （< 0.0015） | 0.01 | 0.05 | 0.01 | 0.02 | 0.04 |
4. Chromium (Cr) | ND （< 0.0008） | 0.05 | 0.1 | 0.02 (Cr6+) | 0.025 | 0.05 |
5. Cadmium (Cd) | ND （<0.0008） | 0.005 | 0.005 | 0.003 | 0.005 | 0.003 |
6. Barium (Ba) | 0.007 | 2.0 | 2.0 | - | - | 1.3 |
7. Antimony (Sb) | ND （<0.0007） | 0.01 | 0.006 | 0.02 | 0.01 | 0.02 |
8. Nickel (Ni) | ND （< 0.0007） | 0.02 | - | 0.02 | 0.02 | 0.07 |
9. Mercury (Hg) | ND （< 0.00003） | 0.001 | 0.002 | 0.0005 | 0.001 | 0.006 |
10.Cyanide (CN-) | ND （< 0.00052） | 0.05 | 0.2 | 0.01 | 0.05 | - |
11.NO- 2-N (Nitrite Nitrogen, as N) | ND （< 0.0003） | 0.1 | 1 | 0.04 | 0.5 | 3 |
| Parameters | TWD Tap Water Quality | Taiwan (2022) | U.S. (2018) | Japan (2022) | E.U. (2020) | W.H.O. (2022) |
|---|---|---|---|---|---|---|
12.Trihalomethanes (THMs) | 0.00800 | 0.08 | 0.08 | 0.1 | 0.1 | *8 |
13. Haloacetic acids (sum of concentrations of | 0.00734 | 0.060 | 0.06 | 0.02 (MCAA) 0.03(DCAA) 0.03(TCAA) | 0.06 | 0.02(MCAA) 0.05(DCAA) 0.2(TCAA) |
14. Bromate | ND （<0.00087） | 0.01 | 0.01 | - | 0.01 | 0.01 |
15. Chlorite | ND （<0.00046） | 0.7 | 1 | 0.6 | 0.25 | 0.7 |
| Parameters | TWD Tap Water Quality | Taiwan (2022) | U.S. (2018) | Japan (2022) | E.U. (2020) | W.H.O. (2022) |
|---|---|---|---|---|---|---|
16.Trichloroethylene | ND （<0.00021） | 0.005 | 0.005 | 0.01 | *10 | 0.008 |
17.Carbon Tetrachloride | ND （<0.00022） | 0.005 | 0.005 | 0.002 | - | 0.004 |
18.1,1,1-Trichloroethane | ND （<0.00021） | 0.20 | 0.20 | 0.3 | - | - |
19.1,2-Dichloroethane | ND （<0.00027） | 0.005 | 0.005 | 0.04 | 0.003 | 0.03 |
20.Vinyl chloride | ND （<0.00003） | 0.0003 | 0.002 | - | 0.0005 | 0.0003 |
21.Benzene | ND （<0.00023） | 0.005 | 0.005 | 0.01 | 0.001 | 0.01 |
22.Para-Dichlorlbenzene | ND （<0.00041） | 0.075 | 0.075 | - | - | 0.3 |
23.1,1-Dichloroethene | ND （<0.00021） | 0.007 | 0.007 | 0.1 | - | - |
24. Dichloromethane | ND (<0.00038) | 0.02 | 0.005 | 0.02 | - | 0.02 |
25. 1,2-Dichlorobenzene | ND (<0.00046) | 0.6 | 0.6 | - | - | 1 |
26. Toluene | ND (<0.00025) | 0.7 | 1 | 0.4 | - | 0.7 |
27. Xylenes | ND | 0.5 | 10 | - | - | 0.5 |
28. cis-1,2-Dichloroethene | ND (<0.0002) | 0.07 | 0.07 | 0.04*9 | - | 0.05*9 |
29. trans-1,2-Dichloroethene | ND (<0.00028) | 0.1 | 0.1 | 0.04*9 | - | 0.05*9 |
30. Tetrachloroethene | ND (<0.0002) | 0.005 | 0.005 | 0.01 | *10 | 0.1 |
| Parameters | TWD Tap Water Quality | Taiwan (2022) | U.S. (2018) | Japan (2022) | E.U. (2020) | W.H.O. (2022) |
|---|---|---|---|---|---|---|
31.Endosulfan | ND | 0.003 | - | 0.01 | *12 | - |
32.Lindane | ND （<0.000004） | 0.0002 | 0.0002 | - | *12 | 0.002 |
33.Butachlor | ND （<0.00004） | 0.02 | - | 0.03 | *12 | - |
34.2.4-Dichlorophenoxyacetic acid | ND （<0.000024） | 0.07 | 0.07 | 0.02 | *12 | 0.03 |
35.Paraquat*11 | ND （<0.00105） | 0.01 | - | 0.005 | *12 | - |
36.Methomyl | ND （<0.00008） | 0.01 | - | 0.03 | *12 | - |
37.Carbofuran | ND （<0.00034） | 0.02 | 0.04 | 0.0003 | *12 | 0.007 |
38.Isoprocarb | ND （<0.00048） | 0.02 | - | 0.01 | *12 | - |
39.Methamidophos | ND （<0.000055） | 0.02 | - | - | *12 | - |
40.Diazinon | ND （<0.000059） | 0.005 | - | 0.003 | *12 | - |
41.Parathion | ND （<0.000086） | 0.02 | - | - | *12 | - |
42.EPN | ND （<0.000169） | 0.005 | - | 0.004 | *12 | - |
43.Monocrotoohos | ND （<0.000100) | 0.003 | - | - | *12 | - |
| Parameters | TWD Tap Water Quality | Taiwan (2022) | U.S. (2018) | Japan (2022) | E.U. (2020) | W.H.O. (2022) |
|---|---|---|---|---|---|---|
44. Dioxin (pg WHO-TEQ/L) | 0.003 | 3 | 3x10-8 *13 | 1 | - | - |
(B) Substances probably affecting health
| Parameters | TWD Tap Water Quality | Taiwan (2022) | U.S. (2018) | Japan (2022) | E.U. (2020) | W.H.O. (2022) |
|---|---|---|---|---|---|---|
1.Fluoride (F-) | 0.07 | 0.8 | 4.0*14 | 0.8 | 1.5 | 1.5 |
2.NO3-N (Nitrate Nitrogen ,As N) | 0.34 | 10.0 | 10.0 | 10 | 50 | 50 |
3.Silver (Ag) | ND （<0.0008） | 0.05 | 0.1*5 | - | - | - |
(C)Substances affecting palatability
| Parameters | TWD Tap Water Quality | Taiwan (2022) | U.S. (2018) | Japan (2022) | E.U. (2020) | W.H.O. (2022) |
|---|---|---|---|---|---|---|
1.Iron (Fe) | ND （<0.0019） | 0.3 | 0.3*5 | 0.3 | 0.2 | - |
2.Manganese (Mn) | ND （<0.0008） | 0.05 | 0.05*5 | 0.05 | 0.05 | 0.08 |
3.Copper (Cu) | ND （<0.0008） | 1.0 | 1.0*5 1.3*7 | 1.0 | 2.0 | 2.0 |
4.Zinc (Zn) | ND （<0.0008） | 5.0 | 5.0*5 | 1.0 | - | - |
5.Sulfate (SO4-2) | 12.3 | 250 | 250*5 | - | 250 | - |
6.Phenols | ND （<0.00047) | 0.001 | - | 0.005 | - | - |
7.MBAS (Anionic Surfactant, Methylene Blue Activated Substance) | ND （<0.0044） | 0.5 | - | 0.2 | - | - |
8.Chloride (Cl-) | 5.04 | 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 | 33.1 | 300 | - | 300 | - | - |
11.Total Dissolved Solids | 61 | 500 | 500*5 | 500 | - | - |
12. Aluminum (Total Al) | 0.051 | 0.2 | 0.05~0.2*5 | 0.2 | 0.2 | - |
D. Residual chlorine | 0.62 | 0.2~1.0 | 4 | 1.0 | - | 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. 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.
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. 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.
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