Every Indian citizen has a right to get safe drinking water. It is one of the Sustainable Development Goals (SDGs) that every country in the world should achieve before 2030.

Therefore, the BIS (Bureau of Indian Standards) has stipulated specific safe drinking water guidelines. We shall go through the guidelines later on in this article. Before that, let us stare at some hard facts.

As per the 2011 Census, 68.84% of the Indian population lives in rural areas. Supplying pure and safe drinking water to a population of this magnitude is a tremendous challenge.

If you take the informed and the uninformed public drinking water sources together, India has about 60 lakhs such sources for rural India.

About 37.7 million people in India suffer from waterborne diseases out of which 1.5 million children die of diarrhoea.

Aquifers fulfil about 85% of India’s drinking water requirements, but their levels are falling considerably.

About 10.28% of all habitations are affected by poor water quality.

Groundwater in various parts of India has a high level of fluoride content. Therefore, more than 62 million people suffer from various degrees of fluorosis of which children below 14 years constitute more than 6 million.

It is an estimate that India will become a water-stressed nation by 2020.

India has 75.8 million people without access to clean water.

It is an alarming figure. With this background, let us look at the look at the aspects affecting water quality before discussing the BIS safe drinking water guidelines.

In its purest state, water is a tasteless, colourless, and odourless liquid. However, water has the reputation of being one of the best naturally occurring solvents in the planet.

As any substance will dissolve in water to some extent, it is not easy to find water in its pure state. It contains various impurities such as gases, solids, and so on. As water percolates into the earth, it dissolves the minerals present in it.

We have seen above that there are more than 60 lakh water sources in India. The surface water comprises of rivers, streams, ponds, lakes, and reservoirs. You have wells, springs, mines, and tube wells as sources of groundwater.

Groundwater comprises of dissolved minerals such as calcium, magnesium, sodium, and so on. These dissolved minerals are in the form of carbonates, nitrates, and other salts. You also refer to them as Totally Dissolved Salts (TDS).

At the same time, you have heavy metals like arsenic, lead, cadmium, mercury, and others contaminating water. Many areas in India contain fluorides as well. Also, you have organic impurities like residual animal and vegetable matter.

Surface water contains these organic impurities, human waste, and industrial waste. Groundwater is relatively free from such contaminants because of the strata of the soil act as natural filters.

Now, we know that pure water does not have any taste. Water needs to have some TDS in it to be palatable. The BIS has stipulated specifications for the acceptable and permissible levels of TDS. We shall look into these aspects as well.

We reproduce below the BIS 10500-2012 standard that applies to the purity levels acceptable for human consumption.

ParameterDesirable LimitPermissible LimitRisks or EffectsSources of ImpurityTreatment
Colour5 Hz25 HzVisible tint results in decrease in acceptanceIron, Copper, Manganese, Tannins, Natural DepositsFiltration, Distillation, Ozonisation, Reverse Osmosis
OdourAgreeableAgreeableRotten Eggs, Musty, ChemicalChlorine, Hydrogen sulphide, Organic matter, Sewage contamination, Methane GasActivated Carbon, Oxidation, Filtration, Air stripping
pH6.5 to 8.5No RelaxationLow pH – Metallic taste
High pH – Bitter taste
NaturalIncrease pH by adding soda ash
Decrease pH by adding vinegar or citric acid
TDS5002000Hardness, Scaly deposits, sediments, cloudy coloured water, salty taste, corrosion of pipesSewage, animal waste, landfills, nature of the soil, Dissolved minerals, iron, manganeseReverse Osmosis, Distillation, Ion Exchange
Hardness300600Scaling in utensils and hot water systems, soap scumsDissolved calcium and magnesium from the soil, minerals containing limestoneWater softener Ion Exchange, Reverse Osmosis
Alkalinity200600Low alkalinity causes deterioration of plumbing, increase chances of presence of heavy metalsPipes, landfills,Neutralizing agent
Iron0.3 mg/l1.0 mg/lBrackish Colour, Rusty sediment, bitter taste, brown stains, discoloured beveragesLeaching of cast iron pipes, NaturalOxidizing filter, Green-sand Mechanical filter
Manganese0.1 mg/l0.3 mg/lBrownish colour, black stains on clothes, bitter tasteLandfills, deposits in rocks and soilIon Exchange, Chlorination, Oxidizing filter, Green-sand Mechanical filter
Sulphate200 mg/l400Bitter, medicinal taste, scaly deposits, rotten-egg odour, laxative effectsHuman and animal sewage, a by-product of coal mining industry, industrial waste, Natural depositsIon Exchange, distillation, Reverse Osmosis
Nitrate45 mg/lNo RelaxationBlue baby disease in infantsLivestock, septic systems, manure lagoons, fertilisers, household wasteIon Exchange, Distillation, Reverse Osmosis
Chloride250 mg/l1000 mg/lHigh blood pressure, salty taste, corrosion in pipes, blackening of stainless steelFertilisers, industrial wastes, minerals, sea waterDistillation. Activated Carbon, Reverse Osmosis
Fluoride1.0 mg/l1.5 mg/lBrownish discolouration of teeth, bone damageIndustrial waste, GeologicalActivated Alumina, Distillation, Reverse Osmosis, Ion Exchange
Arsenic0.01 mg/l0.05 mg/lLoss of weight, depression, lack of energy, Carcinogen agentPesticides, improper waste disposal, glass industry, semiconductor industry, miningActivated Alumina filtration, Reverse Osmosis, Distillation, Chemical precipitation, Ion Exchange
Chromium0.05 mg/lNo RelaxationSkin irritation, skin and nasal ulcers, lung tumours, gastrointestinal effects, nervous and circulatory system damage, accumulation in spleen, bones, kidneys, and liverSeptic systems, Industrial waste, mining, GeologicalIon Exchange, Reverse Osmosis, Distillation
Copper0.05 mg/l1.5 mg/lAnaemia, Digestive problems, liver and kidney damage, Gastrointestinal irritations, bitter taste, Blue-green stainsLeaching from copper water pipes, algae treatment, Industrial and mining waste, wood preservatives, Natural depositsIon Exchange, Reverse Osmosis, Distillation
Cyanide0.05 mg/lNo RelaxationThyroid, nervous system damageFertiliser, electronics and steel industry, Plastics miningIon Exchange, Reverse Osmosis, Chlorination
Lead0.01 mg/lNo RelaxationMental retardation, interference in kidney and neurological functions, hearing loss, blood disorders, hypertension, death at high levelsPaints, diesel combustion, pipes and solder, discarded batteries, leaded gasoline, Natural depositsIon Exchange, Activated Carbon, Reverse Osmosis, Distillation
Mercury0.001 mg/lNo RelaxationLoss of vision and hearing, deterioration of intellect, kidney and nervous system disorders, death at high levelsFungicides, batteries, mining, electrical equipment, plant, paper, and vinyl chloride, Natural depositsReverse Osmosis, Distillation
Zinc5 mg/l15 mg/lMetallic tasteLeaching of galvanized pipes, paints, dyes, Natural deposits
Total Coliform Bacteria

E-Coliform Bacteria


not detectable in any 100 ml sample15 mg/lGastrointestinal illnessLivestock, septic systems, household wastes, manureChlorination, Ultraviolet, Distillation, Iodination

Solutions to the problem

If you go through the above table, you will understand the need for installing high-quality water purifiers. It can help eliminate these contaminants and ensure pure and safe drinking water for all.

Some of the best water purification technologies are Reverse Osmosis, Ion Exchange, and Ultraviolet water purification.

The municipalities and other governmental organisations can take the initiative and see to it that it supplies RO purified water to the residents of the cities and villages.

Every household has a responsibility to ensure pure and safe water. A little care can go a long way in solving the problem. India has to go a long way in this regard if they have to achieve the Sustainable Development Goals by 2030.

Sources: indiawaterportalbureau of indian standards

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