Everything you want to know about drinking water

Why is drinking water important?

Water is extremely crucial for the proper functioning of the human body. Infact, about 60 percent of the human body is made up of water while blood consists of 90 percent water. Water lubricates the joints, forms an integral part of saliva and mucus and most importantly carries oxygen to different parts of the body through the blood. It also provides a cushion for the brain, spinal cord and other sensitive tissues; keeps the skin healthy; regulates body temperature; helps in digestion; flushes out waste and maintains functioning of the kidneys; helps maintain blood pressure and dissolves vital minerals and nutrients in the body.

What are the sources of drinking water?

Freshwater i.e. water available for drinking is a rare and valuable resource! While water covers two thirds of the earth's surface, most of it is salty and not suitable for drinking. Only 2.7 percent of the available water on earth is freshwater and only 1 percent of the available freshwater can be accessed for use from rivers, lakes and groundwater. 

What is potable drinking water?

Although we need to drink a good amount of water to stay healthy, this drinking water needs to be potable i.e. suitable for human consumption. It has to be

drinkable

and

safe

. 

Drinkable water should appear clear to the naked eye and be free of unpleasant odours, tastes and colours and be of optimum temperature. In addition to this, it has to be safe and free from toxins, carcinogens, pathogenic micro-organisms and any other factors causing health hazards.

Safe water is essential for all domestic uses that include drinking, food preparation and personal hygiene.  Safe water is not necessarily pure, it can have some impurities like traces of salts such as magnesium, calcium, carbonates, bicarbonates etc.

A 'safely managed drinking water service" is "one located on premises, available when needed and free from contamination". According to the WHO/UNICEF Joint Monitoring Programme (JMP) for Water Supply Sanitation and Hygiene,  “safe drinking water” is defined as water from an “improved water source,” which includes household connections, public standpipes, boreholes, protected dug wells, protected springs and rainwater collections. According to the same organisation, “access to safe drinking water” is defined as the availability of at least 20 l per person per day from an “improved” source within 1 km of the user’s dwelling.

What are the sources of drinking water in India?

Drinking water in India is mostly derived from groundwater that is pumped via handpumps from borewells, tubewells, dugwells, and surface water sources like rivers, streams, ponds and lakes.

The National Sample Survey Office's (NSSO) data - 76th round provides an overview of the various sources of drinking water available in urban and rural India.

The data shows that groundwater is the most reliable source of drinking water for nearly 43 percent of the rural population in the country.

How is drinking water accessed in India?

Access to water continues to be a challenge in India.  The NSSO data shows that  only one in every five households have access to piped water connections in the country. Rural areas continue to lag behind in terms of access to piped water as compared to urban.

Around 58.3 percent of households still rely on hand pumps, tube wells, public taps, piped water from neighbour, protected or unprotected wells, and private or public taps for their water.

As high as 48.6 percent rural households and 28 percent urban households have to survive without access to an improved source (devoid of contamination/safe) of drinking water throughout the year. Also, 11.3 percent households do not get sufficient drinking water from their primary sources throughout the year.

The recently released NFHS-5 (2019-2020) data also shows that while access to drinking water from improved sources has increased in the 22 states surveyed as compared to NFHS (2015-2016) , rural areas still continue to lag behind as compared to urban in terms of access to safe drinking water.

How does drinking water become unsafe?

Water sources can get polluted because of a range of harmful contaminants. The common contaminants occurring in drinking water can be classified into:

• Inorganic contaminants

  : include metals such as fluoride, arsenic, lead, copper, chromium, mercury, antimony, cyanide that can get into drinking water (surface as well as groundwater) from natural sources, industrial processes, as well as from plumbing systems.

• Organic contaminants

  include pesticides, untreated domestic and industrial wastes etc that can get into rivers, lakes, ponds and even groundwater. Contamination through organic materials can cause serious health problems like cancers, hormonal disruptions, and nervous system disorders.

• Biological contaminants

  include the presence of living organisms, such as algae, bacteria, protozoa or viruses in the water. Each of these can lead to a range of health problems among humans.

• Radiological contaminants

  include radioactive materials that are found naturally in the soil or rocks or generated through industrial wastes that can get mixed with drinking water (surface water as well as groundwater) at the source.

Know more on conventional and emerging contaminants in drinking water here

Is drinking water in India safe?

A large proportion of people do not have access to water within the house, increasing the chances of infections. Surface water sources too are highly contaminated in India. Poor sewage disposal mechanisms lead to most of the untreated sewage being drained into rivers and lakes that serve as reservoirs of microbial contamination. Poor access to safe water sources and toilets and open defecation and poor WASH practices lead to high instances of waterborne diseases in the country.

Release of untreated industrial and pharmaceutical wastes into the surface water sources has led to dangerous levels of organic and inorganic pollutants into the surface water bodies in India, making it unfit for consumption.

Groundwater resources in the country have also been found to be highly polluted due to presence of fluoride, arsenic, nitrates, iron, heavy metals as well as due to leaching of harmful pesticide and fertiliser residues. Toxins from untreated industrial wastes and landfills as well as bacterial contaminants from the surface soil and water sources can also contaminate groundwater.

What are the health impacts of contaminated drinking water?

Inorganic pollutants in water can be extremely harmful and lead to a range of chronic and fatal health problems ranging from poisoning to organ damage and cancers. For example, high levels of arsenic, lead, asbestos, cyanide, copper etc in water can be extremely harmful to health and can lead to problems like dental and skeletal fluorosis  in case of excessive levels of fluoride, arsenicosis due to high levels of arsenic and endocrine disruptions and neurological damage due to presence of excessive amounts of mercury.

Organic and radiological contaminants can also lead to a range of dangerous health impacts on the body such as cancers, liver and kidney damage, reproductive and endocrine disorders, birth defects etc.

Read more on organic, inorganic and radiological contaminants of drinking water and their health effects here.

The WHO factsheets on individual chemical contaminants of drinking water and their health impacts can be accessed here

Biological contamination of water due to viruses, bacteria and protozoa can lead to a range of waterborne diseases such as diarrhoea, dysentry, cholera, typhoid, hepatitis that can prove fatal if not treated in time.

What are the health impacts of contaminated drinking water in India?

 Waterborne diseases are rampant in India due to high levels of biological contamination of water. Annually about 37.7 million Indians are affected by waterborne diseases, 1.5 million children die of diarrhoea and 73 million working days are lost leading to an economic burden of $600 million a year.

Waterborne diseases such as cholera, acute diarrhoeal diseases, typhoid and viral hepatitis  have caused 10,738 deaths, over the last five years since 2017. Of this, acute diarrhoeal diseases have caused maximum deaths followed by viral hepatitis, typhoid and cholera.

Water (sourced from groundwater) contamination due to fluoride, arsenic, iron, manganese, uranium and radon is high in selected states in India. Central Groundwater Board (2014) data reveals that as high as 66 million people are drinking water with fluoride levels beyond permissible limits in India leading to dental and skeletal fluorosis. Contamination of drinking water with arsenic is rampant in the states of West Bengal and Bihar besides Uttar Pradesh, Madhya Pradesh and Karnaka leading to arsenic poisoning and cancers. 

Studies by the Central Water Commission (2015) also show that rivers (surface drinking water sources) in India are loaded with toxic heavy metals such as lead, arsenic, copper, cadmium, mercury and nickel that are highly toxic and carcinogenic way beyond standards prescribed by Indian Council of Medical Research (ICMR) and Bureau of Indian Standards (BIS).

How is safety of drinking water measured?

Access to affordable, safe drinking water is critical for health and development. There are basic quality standards, norms, criteria and indicators that have been designed to ensure safety of drinking water.

Water quality is based on a set of biological, physical and chemical variables, which are closely linked to the intended use of water. Drinking water is expected to be free from harmful pathogens and toxic chemicals.

A standard for drinking water quality is thus the reference that will ensure that the tested water will not pose any threat or harm to human health. There are a number of standard guidelines for ensuring quality of drinking water such as those by the World Health Organisation, Commission for European Union, U.S. Environmental Protection Agency, Canada etc .

To know more on water quality, view this video below:

Video Source: People's Science Institute, Dehradun

Why is it important to measure water quality?

View this video to know more

Video Source: People's Science Institute, Dehradun

How is drinking water safety measured in India?

Click here to know more on rules, regulations and standards concerning water

Click here to know more about total dissolved solids (TDS) in water

How is water quality checked?

Drinking water quality is checked against the standards mentioned above by following certain guidelines or protocols for water quality monitoring.

Read this document by the World Health Organisation that provides the guidelines for assessing drinking water quality

Where can you get water quality checked in India?

Water gets tested in accredited water quality testing laboratories in India.

There continues to be a shortage of standard water quality testing laboratories in the country

Taking into consideration this shortage of water quality testing laboratories in the country, the Department of Drinking Water and Sanitation (DDWS), has directed the states to open up water testing laboratories to the public. One of the mandatory guidelines under the Har Ghar Nal Se Jal scheme is that states will have to establish water testing laboratories at all levels — state, districts and blocks.

The DDWS now also plans to help States and Union Territories (UTs) in setting up, upgrading and improving the functioning of drinking water quality testing laboratories by providing technical and financial support under the Jal Jeevan Mission.

Who ensures access to safe drinking water in the country?

Ensuring safe water supply and sanitation is a state responsibility under the Indian Constitution. The state-level agency is in charge of planning and investment, while the local government (Urban Local Bodies) take care of the operation and maintenance. In recent years, the private sector has also started playing a role in operation and maintainence of urban water systems on behalf of ULBs.

There are about a 100,000 rural water supply systems in India. In some states, responsibility for service provision is in the process of being partially transferred from State Water Boards and district governments to Panchayati Raj Institutions (PRI) at the block or village level.

At present, states plan, design and execute water supply schemes through their State Departments (of Public Health Engineering or Rural Development Engineering) or State Water Boards.

How is drinking water treated?

The suitability of technology for treating drinking water depends on the nature and extent of contamination, infrastructure available such as manpower, availability of chemicals etc, affordability and acceptability among the populations using them. Some of the common water purification methods that are used for treating water include:

• Sedimentation or settling
• Boiling/distillation
• Chemical treatment (precipitation/coagulation/adsorbents)
• Disinfection and filtration

What kind of residential water filter do you need to buy for your home, click here to find out!

For information on drinking water treatment technologies that can be used in India by the Department of Drinking Water and Sanitation (DDWS), Government of India click here

What are the traditional water treatment methods used by rural communities in India. Click here to find out!

For details on the suitable methods and technologies that can used for treatment of drinking water by the World Health Organisation (WHO), click here.

Documents on water treatment options for ensuring drinking water safety by the World Health Organisation (WHO) can be accessed here.