Safe drinking-water is a human right. Through Sustainable Development Goal 6 – to ensure availability and sustainable management of water and sanitation for all by 2030 – the world reaffirmed its commitment to ensure safe drinking-water for all.

Inadequate management of urban, industrial and agricultural wastewater means the drinking-water of hundreds of millions of people is dangerously contaminated or chemically polluted. Natural presence of chemicals, particularly in groundwater, can also be of health significance. Re-use of wastewater to recover water, nutrients or energy is becoming an important strategy.

A report prepared in association with Ministry of Jal Shakti and Ministry of Rural Development states, India is home to 17% of world’s population but has only 4% of the world’s fresh water resources.

IS 10500 (Second Revision):2012

This Indian Standard (Second Revision) was adopted in 2012. The standard specifies the acceptable limits and the permissible limits in the absence of alternate source. It recommends that the acceptable limit is to be implemented as values in excess of those mentioned under ‘Acceptable’ render the water not suitable.

CPCB, CSE, National Environmental Engineering Research Institute, Institution of Public Health Engineers, Natural Resource Economics and Management Foundation, BIS Drinking Water Sectional Committee, NABL, Food and Agriculture Division Council, Central Water Commission and the Jal Ministry are some of the agencies involved with drinking water standards formulation and enforcement.

WHO Guidelines

WHO has recently updated Guidelines for Drinking-Water Quality (GDWQ): 4th edition: 2022 and GDWQ: small water supplies: 2024.

Key updates included in the 2022 version of the Guidelines are:

• application of the screening values and guidance levels, and management;

• use of an alert level framework;

• Recommends that an overall health protection strategy to be incorporated into a legislative and regulatory framework;

• The judgement of safety—or what is an acceptable level of risk in particular circumstances—is a matter in which society as a whole has a role to play.

• Although the Guidelines describe a quality (guideline values) of water that is acceptable for life- long consumption, a continuous effort should be made to maintain drinking water quality at the highest possible level.

WHO Sanitary Inspection Packages

• A supporting tool for the Guidelines for drinking-water quality: small water supplies:2024 is a compilation of critical inspection forms for the inspecting teams at rural or urban scale.

Portable document format (PDF) and editable versions of the sanitary inspection packages can be downloaded from https://www.who.int/teams/environment-climate-change-andhealth/water-sanitation-and-health/water-safety-and-quality/water-safety-planning/sanitaryinspection- packages.

 Drinking water production involves multifarious stakeholders including the global environment. Few critical aspects and stakeholders of drinking water management are described subsequently.

Control Measures, Operational Monitoring, Surveillance and Quality Control

• Control measures may include pretreatment, coagulation, flocculation, sedimentation, filtration and disinfection.

• Primary disinfection (Chlorine, Chlorine dioxide):Free chlorine × contact time predicts efficacy.Turbidity and chlorine-demanding solutes inhibit this process; hence, turbidity should be kept below 1 NTU to support effective disinfection.

• The frequency of operational monitoring varies with the nature of the control measure— includes observing or testing parameters such as turbidity, chlorine residual or structural integrity.

• The two functions of surveillance and quality control are best performed by separate and independent entities to obviate conflict of interest.

Water Safety Plans

• Overall control of the microbial and chemical quality of drinking-water requires the development of Water safety plans, that, when implemented, ensure that numbers of pathogens and concentrations of chemicals present a negligible risk to public health.

Community Management

• Setting up hygiene and health educational programmes to enhance awareness;

• Importance of surveillance and a community response;

• skilling to perform that role;

• Pollution protection.

NABL

National Accreditation Board for Testing and Calibration Laboratories (NABL) is an accreditation body, with its accreditation system established in accordance with ISO/ IEC 17011. It revises and publishes, every month, a Directory of Accredited Testing Laboratories of India (NABL 400). These NABL accredited labs are the Gold standard for conducting Drinking water testing as per the Acceptable limits of IS:10500 and also WHO GDWQ, 2022.

Final Recommendations

• IS 10500 could incorporate existing local mineral zonation and micro-zonation maps to enable treated water stabilisation / remineralisation prior to supplies.

• Constitute a legal and regulatory framework of Water Safety Plan (WSP).

• Define the roles and responsibilities of all stakeholders including local communities.

• Conventional flocculation and filtration processes are critical and should be mandatory in all water supply installations.

• Stipulate Minimum frequency of WSP audits and SIs (Sanitary Inspections) by the surveillance agencies.

• Classifying Water treatment plants according to the complexity of treatment and Differentiate operator certification requirements by the size and complexity of water facilities.

• Requirements for the training, skills and/or certification of operators should be included in regulations and associated frameworks.

• The WHO GDWQ Table A3.3 Guideline values for chemicals that are of health significance in drinking-water should be included in toto in our national standard duly considering the ADIs (Acceptable Daily Intake).

• The WHO GDWQ ANNEX 5:Treatment methods and performance to be incorporated in our national standard for compliance.

• Implement and enforce the WHO Sanitary inspection packages including the Sanitary inspection form, Technical fact sheet and Management advice sheet.

• The monitoring & testing frequency range in Tables 3.4 to 3.9 of WHO Small water supplies 2024 to be implemented across all professional water purification/disinfection/ supplying installations pan India.

• Regulations should stipulate what, when, how and between whom information should be shared during normal operations.

• Independent, private NABL labs to be selected for regular water testing based on their integrity and excellence.

• The NABL test results of every water supply installation should be printed on legible flex or LED boards and displayed prominently for public knowledge and right to information.

• The DMs/DC, Mayors and the CMOs of every city / district / metro should be the enforcement forces on the ground.

• Few critical Testing related to health, environment, regulatory compliances, pollution should be regularly audited by NABL for its constituent accredited labs.

• IS 10500 should delete the Permissible limits in absence of alternate source and publish those limits in a separate IS (Indian Standard) to obviate the present confusion in the water supply agencies and NABL labs which provide a compliant report even though water not suitable for drinking as per Acceptable limits of the same IS 10500.

• Revision of IS 10500 in consonance with WHO GDWQ, 2022, Guidelines for drinking water quality: small water supplies, 2024 and WHO’s Sanitary inspection packages, 2024 editions.

 • Acceptable limits of IS 10500 should be legally enforced across all bulk water supply purification and supply installations.

Colonel Mohit Nangia, Veteran is an Engineer Officer. He can be contacted at mohitnangia@gmail.com.