IS 10500:2012 - Indian Standard for Drinking Water Specification (Second Revision)

IS 10500:2012 - Indian Standard for Drinking Water Specification (Second Revision)

Bureau of Indian Standards

This Indian Standard (Second Revision) was adopted by the Bureau of Indian Standards, after the draft finalized by the Drinking Water Sectional Committee had been approved by the Food and Agriculture Division Council. The Bureau of Indian Standards Act is an act to provide for the establishment of a national standards body for the harmonious development of the activities of standardisation, conformity assessment and quality assurance of goods, articles, processes, systems and services and for matters connected therewith or incidental thereto.

Background and Development

This standard was originally published in 1983. A report prepared by the World Health Organization in cooperation with the World Bank showed that in 1975, some 1,230 million people were without safe water supplies. These appalling facts were central to the United Nations decision to declare an International Drinking Water Supply and Sanitation decade, beginning in 1981. Further, the VI Five-Year Plan of India had made a special provision for availability of safe drinking water for the masses.

Water Quality Challenges in India

As per the eleventh five year plan document of India (2007-12), there are about 2.17 lakh quality affected habitations in the country with more than half affected with excess iron, followed by fluoride, salinity, nitrate and arsenic in that order. Further, approximately:

  • 10 million cases of diarrhea occur every year
  • More than 7.2 lakh typhoid cases annually
  • 1.5 lakh viral hepatitis cases annually

A majority of these cases are contributed by unclean water supply and poor sanitation.

Revision Objectives

The eleventh five year plan document of India (2007-2012) recognizes dealing with the issue of water quality as a major challenge and aims at addressing water quality problems in all quality affected habitations with emphasis on:

  • Community participation and awareness campaigns
  • Top priority to water quality surveillance and monitoring
  • Setting up of water quality testing laboratories strengthened with qualified manpower, equipment and chemicals

International Alignment

The second revision was undertaken to upgrade the requirements of the standard and align with internationally available specifications on drinking water. Assistance has been derived from:

  1. EU Directives relating to the quality of water intended for human consumption (80/778/EEC) and Council Directive 98/83/EC
  2. USEPA standard — National Primary Drinking Water Standard. EPA 816-F-02-013 dated July, 2002
  3. WHO Guidelines for Drinking Water Quality. 3rd Edition Vol. 1 Recommendations, 2008

Manual on Water Supply and Treatment, third edition — revised and updated May 1999, Ministry of Urban Development, New Delhi

Key Updates in Second Revision

This revision includes additional requirements for:

  • Ammonia, chloramines, barium, molybdenum, silver, sulfide, nickel
  • Polychlorinated biphenyls and trihalomethanes

Modified requirements for:

  • Color, turbidity, total hardness, free residual chlorine, iron, magnesium
  • Mineral oil, boron, cadmium, total arsenic, lead
  • Polynuclear aromatic hydrocarbons, pesticides and bacteriological requirements

New inclusions:

  • Virological examination requirements and test methods
  • Requirements and test methods for cryptosporidium and giardia

Scope

This standard prescribes the requirements and the methods of sampling and test for drinking water.

Terminology

Drinking Water — Water intended for human consumption for drinking and cooking purposes from any source. It includes water (treated or untreated) supplied by any means for human consumption.

Requirements Structure

This standard specifies acceptable limits and permissible limits in the absence of alternate source.

The framework operates as follows:

  • Acceptable limit should be implemented as standard values
  • Values exceeding acceptable limits render water not suitable for consumption
  • Such values may be tolerated only in the absence of an alternative source
  • If values exceed the permissible limits indicated under ‘permissible limit in the absence of alternate source’, the sources must be rejected

Water Quality Parameters

  1. Organoleptic and Physical Parameters

These include characteristics like color, odor, pH value, taste, turbidity, and total dissolved solids that affect the aesthetic quality of water.

  1. General Parameters Concerning Substances Undesirable in Excessive Amounts

This category covers elements and compounds that are generally not harmful in small quantities but can cause problems when present in excessive amounts, such as aluminum, calcium, chloride, fluoride, iron, manganese, and sulfate.

  1. Parameters Concerning Toxic Substances

These are substances that are harmful even in small quantities, including heavy metals like cadmium, lead, mercury, and toxic compounds like cyanide and pesticides.

  1. Parameters Concerning Radioactive Substances

This covers alpha and beta emitters that may be present in water sources.

  1. Pesticide Residues

Specific limits are established for various pesticides commonly found in water sources, based on consumption patterns, persistence, and available manufacturing data.

Bacteriological Requirements

Water in Distribution System

Ideally, all samples taken from the distribution system, including consumers’ premises, should be free from coliform organisms. The standard specifies detailed bacteriological quality requirements for:

  • All water intended for drinking
  • Treated water entering the distribution system
  • Treated water in the distribution system

Key Requirements:

  • E. coli or thermotolerant coliform bacteria shall not be detectable in any 100 ml sample
  • Total coliform bacteria shall not be detectable in treated water samples
  • Immediate investigative action is required if bacteria are detected

Virological Requirements

General Principles

  • All samples should ideally be free from viruses
  • Viruses are generally resistant to disinfectants and get protected by particulate and organic matter in water
  • MS2 phage are indicators of viral contamination in drinking water

Disinfection Effectiveness

  • A redox potential of 650 mV will cause almost instantaneous inactivation of even high concentrations of viruses
  • In practice, >0.5 mg/l of free chlorine for 1 hour is sufficient to inactivate viruses in water free from particulates and organic matter
  • Various oxidants can achieve virus inactivation: iodine, ozone, and potassium permanganate

Testing Requirements

  • MS2 phage shall be absent in 1 liter of water
  • If MS2 phage are detected, virological examination shall be done by PCR method
  • If viruses are detected, immediate further investigation is required

Biological Requirements

General Approach

All samples should ideally be free from biological organisms. Biological examination helps in:

  • Determining causes of objectionable tastes and odors
  • Controlling remedial treatments
  • Interpreting chemical analysis results
  • Explaining causes of clogging in distribution pipes and filters

Parasites and Organisms

  • Cryptosporidium shall be absent in 10 liters of water
  • Giardia shall be absent in 10 liters of water
  • Water shall be free from microscopic organisms such as algae, zooplanktons, flagellates, parasites and toxin producing organisms

Special Considerations

  • Chlorination at normal dosages is ineffective against certain parasites, including amoebic cysts
  • Strict precautions against back-syphonage and cross-connections are required
  • Physical improvements can help exclude parasites in well supplies

Water Quality Surveillance

Routine surveillance of drinking water supplies should be carried out by relevant authorities to:

  • Understand the risk of specific pathogens
  • Define proper control procedures

Implement water safety approaches incorporating risk identification

Prevention Measures

Special precautions should be taken to prevent contamination from chlorine-resistant parasites such as cryptosporidium species and giardia.

Sampling

Representative samples of water shall be drawn as prescribed in IS 1622 and IS 3025 (Part 1), ensuring proper collection methods to maintain sample integrity and provide accurate assessment of water quality.

Implementation Guidelines

For Water Utilities

  • Implement acceptable limits as standard operational targets
  • Establish comprehensive monitoring programs
  • Develop risk management strategies for contamination events
  • Ensure adequate treatment processes for virus and parasite removal

For Regulatory Authorities

  • Conduct regular surveillance of water supplies
  • Investigate immediately when quality parameters are exceeded
  • Promote community awareness and participation
  • Strengthen laboratory capabilities for comprehensive testing

For Consumers

  • Be aware of water quality in their area
  • Report taste, odor, or appearance issues promptly
  • Understand the importance of protected water sources
  • Support community water quality initiatives

 

Note: This document provides an overview of the IS 10500:2012 standard. For complete technical specifications, detailed testing methods, and specific limit values, reference should be made to the complete standard document and associated testing protocols by following links:

 

 

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