What is clean water used for domestic purposes in Vietnam? List of clean water quality parameters and permissible limits in Vietnam

What is clean water used for domestic purposes in Vietnam? 

1. Clean water used for domestic purposes is treated water of guaranteed quality, meeting the requirements for human consumption and hygiene (abbreviated as clean water).

2. Sensory parameters are elements of color and taste that can be perceived by human senses.

3. AOAC stands for the English phrase “Association of Official Analytical Chemists” which means Association of Official Analytical Chemists.

4. CFU is an abbreviation of the English phrase “Colony Forming Unit” which means colony forming unit.

5. FCR is an abbreviation of the English phrase “Free Chlorine Residual” which means free residual chlorine.

6. NTU is an abbreviation of the English phrase “Nephelometric Turbidity Unit” which means turbidity unit.

7. SMEWW stands for the English phrase “Standard Methods for the Examination of Water and Waste Water” which means standard methods for testing water and wastewater.

8. TCU is an abbreviation of the English phrase “True Color Unit” which means color measurement unit.

9. US EPA is an abbreviation of the English phrase “United States Environmental Protection Agency” which means the United States Environmental Protection Agency.

List of clean water quality parameters and permissible limits in Vietnam

Note:

- The sign ^(*) only applies to water supply units exploiting underground water.

- The sign ^(**) only applies to water supply units that use chlorine as a disinfection method.

- The mark ^(***) applies only to coastal areas and islands.

- Sign (-) means no unit.

- Both nitrite and nitrate have the ability to create methemoglobin. Therefore, in case these two substances are present in the water at the same time, the total concentration ratio (C) of each substance to their maximum limit (GHD) must not be greater than 1 and is calculated according to the following formula:

C _nitrate / GHG _nitrate + C _nitrite / GHG _nitrite ≤ 1.

Testing of clean water quality parameters in Vietnam

All clean water quality parameters must be performed at a testing laboratory , a certification organization accredited in accordance with TCVN ISO/IEC 17025 and registered for testing activities according to the provisions of Decree No. 107/2016/ND-CP dated July 1, 2016 of the Government on business conditions for conformity assessment services.
2 . Group A clean water quality parameters: All water supply units must conduct testing.
3 . Group B clean water quality parameters: Parameters that must be tested comply with local technical regulations promulgated by the People's Committees of provinces and centrally run cities on the basis of selecting specific parameters, suitable to local actual conditions.
4 . The water supply unit must test all clean water quality parameters of group A and group B in the list of clean water quality parameters specified in Article 4 of this Regulation in the following cases:
a) Before putting into operation for the first time.
b) After upgrading, major repair has an impact on the production system.
c) When there is an environmental incident that threatens to affect clean water quality.
d) When there is a risk in the production process that may affect the quality of clean water or at the request of a competent authority.
dd) Every 3 years since the most recent test of all parameters.
5. Periodic testing :
a) Frequency of testing for group A clean water quality parameters: not less than 01 time/1 month
b) Frequency of testing for group B clean water quality parameters: not less than 01 time/6 months.
c) Depending on the actual situation of the locality, the People's Committee of the province or city directly under the Central Government may prescribe the frequency of testing more than the frequency specified at Points a and b of this Clause.

Number and location of test samples; Sampling method, test method in Vietnam

1. Number of samples taken per test:
a) Water supply units for less than 100,000 people: take at least 03 samples of clean water.
b) Water supply units for 100,000 people or more: take at least 04 samples of clean water and for every additional 100,000 inhabitants, 01 more sample will be taken.
2. Sampling location: 01 sample is taken at the treated water tank of the water supply unit before being put into the distribution pipeline network, 01 sample is randomly collected at the faucet used at the end of the distribution pipeline network, the remaining samples are randomly collected at the faucet used on the distribution pipeline network (including water distribution vehicles such as tank trucks or water tankers).
3. For agencies, units, apartment buildings, dormitories, hospitals, schools, businesses, areas with concentrated water tanks: take at least 02 samples, including 01 sample at the centralized water tank and 01 random sample at the faucet used. If there are 02 or more concentrated water tanks, each tank takes at least 01 sample at the tank and 01 random sample at the faucet used.
4. In case there is a risk of water pollution, epidemic situation: it is possible to increase the number of water samples taken at different locations for testing.

Legal basis: National technical regulation QCVN 01-1:2018/BYT. 

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