Public HealthPH1ADefine drinking water quality standards
In some cases, public health regulators transpose and update health-based limits or minimum requirements for drinking water quality, with reference values assigned to different water quality parameters.
In other cases, regulators have the role of enforcing them. Often, countries look to the ‘WHO guidelines for drinking water quality’ as a reference guide, containing specific sheets that detail known public health implications of contaminants in water, and make recommendations for maximum permissible thresholds. Regulators are obliged to strictly follow these guidelines when agreeing water quality parameters with operators.
Expected outcomes
- National regulators convert public health norms and standards into drinking water quality standards.
- Service operators are legally bound by drinking water standards when providing drinking water services.
- Consumer health is adequately protected.
Examples
In Nicaragua, Technical Standard No. NTON 11-051-19 approved on September 30, 2020, defines drinking water as that which fulfils quality standards for drinking water as described in the WHO Guidelines for Drinking Water Quality and stipulates that water for human consumption and handwashing of agricultural workers must be drinking water.
In Uruguay, UNIT Standard 833:2008 issued by the Uruguayan Institute of Technical Standards establishes a series of requirements that must be met in drinking water for human consumption, regardless of water collection point, treatment type, production and distribution system. The requirements were adopted through a review process essentially based on World Health Organization (WHO) Guidelines. Of the total parameters that have been standardized in the country, 13.04% are below the values defined by the WHO, 7.83% are above WHO values and 46.96% match WHO values, while the WHO does not have reference values for the remaining 32.17% of parameters.
In Kenya, standards are developed by the Kenya Bureau of Standards (KEBS). The role of the Water and Sanitation Regulatory Board (WASREB) is to enforce the following basic requirements for drinking water, that it is: free from pathogenic (disease causing) organisms; contains no chemicals that have adverse or long-term effects on human health; is fairly clear (i.e. low turbidity, little colour); is not saline (salty); contains no compounds that cause an offensive taste or smell; and does not causing an encrustation of the water supply system nor stains clothes washed in it.
Schedule 5 Microbiological limits for drinking water and containerized drinking water (Source: Adopted from KS 05-459: Part 1: 1996)
| SL. NO. | Type of micro-organism | Drinking Water | Containerized Drinking Water | Methods of Test |
| (i) | Total viable counts at 37°C, per ml, max | 100 | 20 | KS 05-200+ |
| (ii) | Coliforms in 250ml | Shall be absent | Shall be absent | KS 05-200 |
| (iii) | E. Coli in 250ml | Shall be absent | Shall be absent | KS 05-200 |
| (iv) | Staphylococcus aureus in 250ml | Shall be absent | Shall be absent | KS 05-200 |
| (v) | Sulphite reducing anaerobes in 50ml | Shall be absent | Shall be absent | KS 05-200 |
| (vi) | Pseudomonas aeruginosa fluorescence in 250ml | Shall be absent | Shall be absent | KS 05-200 |
| (vii) | Streptococuus faecalis | Shall be absent | Shall be absent | KS 05-200 |
| (viii) | Shigella in 250ml | Shall be absent | Shall be absent | KS 05-200 |
| (ix) | Salmonella in 250ml | Shall be absent | Shall be absent | KS 05-200 |
| SL. NO. | SUBSTANCEOR CHARACTERISTIC | UNIT | DRINKING WATER | BOTTLED DRINKING WATER | METHODS OF TEST |
| (i) | Color | True color units | 15+ | 15+ | KS 05-459 |
| (ii) | Taste and odor | Shall not be offensive to consumers | Shall not be offensive to consumers | KS 05-459 | |
| (iii) | Suspended matter | Nil | Nil | KS 05-459 | |
| (iv) | Turbidity | NTU, max | 5 | 1 | KS 05-459 |
| (v) | Total dissolved solids | mg/1, max | 1,500 | 1,500 | KS 05-459 |
| (vi) | Hardness as CaCo3 | mg/1, max | 500 | 500 | KS 05-459 |
| (vii) | Aluminum as A1 | mg/1, max | 0.1 | 0.1 | KS 05-459 |
| (viii) | Chloride as Cl- | mg/1, max | 250 | 250 | KS 05-459 |
| (ix) | Copper as Cu | mg/1, max | 0.1 | 0.1 | KS 05-459 |
Links
Nicaragua: WHO Guidelines for Drinking Water Quality, Technical Standard No. NTON 11-051-19
Kenya: WASREB Water Quality Guidelines:
https://wasreb.go.ke/downloads/Water_Quality_&_Effluent_Monitoring_Guidelines.pdf
WHO Guidelines for Drinking Water Quality:
Internal capacities needed and the role of partners
Establishing drinking water quality standards requires a blend of technical and legal expertise, including an understanding of the current level of water treatment, laboratory testing capacity, and the ambient water quality status of water sources. Development partners could provide technical support ministries of health to translate recommended maximum permissible thresholds from the WHO guidelines to suit local contexts. Regulators can also benefit from such training, by building internal monitoring capacity for actions that they commonly perform on behalf of ministries of health.