Water Resources in India – UPSC

• Water resources are the natural stores and flows of water that can potentially serve as a source of supply: rain and snow, rivers and lakes, and aquifers.
• India holds about 18% of the world’s population on about 4% of its water, so the issue is less the total than where and when the water comes.
  • Rain falls in a short season and unevenly over space, while demand runs all year.
  • Scarcity therefore sits beside floods, and the country is already classed as water stressed.

Water on Earth and in India

Earth’s Water

• About 97% of the water on Earth is salt water. Only about 3% is fresh, and slightly over two-thirds of that fresh water is frozen in glaciers and polar ice caps.
• Most of the unfrozen fresh water lies underground. Only a small fraction sits on the surface or in the air.
• Natural sources of fresh water: surface water, the flow beneath rivers (under-river flow), ground water and frozen water.
• Artificial sources: treated wastewater (reclaimed water) and desalinated seawater. Both cost a great deal, which limits their use.
• About 71% of the planet’s surface is under water, yet the share fit for human use is tiny.

India’s Water Budget

• India’s water resources take in precipitation, surface and ground water storage and hydropower potential.
• Precipitation is the source of nearly all fresh water in India.
  • The average is about 1,170 mm a year, or about 4,000 cubic km (BCM) including snowfall.
  • Of this, about 3,000 cubic km arrives in the monsoon, June to September.
  • An older reckoning puts availability at about 1,720 cubic metres per person a year. That count refers to usable fresh water, not to the rain received.
• Much of the rain never reaches a river. A good part returns to the air by evaporation and transpiration, and a large part percolates to become ground water.
• Some 80% of the area receives 750 mm or more a year, but the rain is uneven in time and in geography.
  • The north-east and north receive far more than the west and south.
  • Monsoon years vary too, so the same basin can move from flood to shortage.
• Snowmelt over the Himalaya after winter feeds the northern rivers to varying degrees, which is why they keep flowing in the dry months.
• The southern rivers show more flow variability over the year.
  • In the Himalayan basin, the seasonal peak brings flooding in some months and scarcity in others.
• A large river system has not removed the shortage. Safe drinking water and irrigation for sustainable farming are short across the country, partly because only a small fraction of recoverable surface water has been harnessed.
• The estimate of the country’s total water has grown with better data:

• Topography and the uneven spread of water mean that only part of this can be used. The long-standing utilisable figure is about 1,122 BCM: 690 BCM of surface water and 432 BCM of ground water.
• Harnessing: India drew about 761 BCM around 2010, about 20% of its precipitation, and part of that came from unsustainable use of ground water.

Surface Water

• Surface water is the water held in rivers, lakes, ponds and canals. Rivers are its main source.
• India has 13 major rivers, with a total catchment of 252.8 million hectares, about 83% of the area of all drainage basins.
  • The Ganga–Brahmaputra–Meghna system is the largest, at about 110 million hectares, more than 43% of the catchment of the major rivers. It holds about 40% of utilisable surface water.
  • Other major rivers: Indus (32.1), Godavari (31.3), Krishna (25.9) and Mahanadi (14.2) million hectares.
  • Medium rivers drain about 25 million hectares more.
• The contrast between Himalayan and Peninsular rivers sets the pattern of supply:
  • Most Himalayan rivers are large and snow-fed, and carry water all year: they are perennial.
  • Peninsular rivers are seasonal, with little or no flow in the dry summer. Most of the monsoon flood runs off to the sea.
  • Even dry Rajasthan and Gujarat can flood, and wet West Bengal can face drought.

• The table shows the core problem: the Brahmaputra has the most water and the least usable share, because terrain and location limit storage.
• One answer proposed to this mismatch is the interlinking of Indian rivers, which moves water from surplus to deficit basins through reservoirs and canals. Of its 30 identified links, only the Ken–Betwa had entered implementation as of August 2026.

Ground Water

How Much There Is

• Ground water is the part of rain and surface water that percolates through soil and rock.
• Successive estimates:

• The 433 BCM long quoted as annual utilisable ground water is, strictly, the total replenishable resource. The figure that can be drawn after natural discharge is lower.
• The board has moved from river basin data to data by State and Union Territory, and has assessed the resource every year since 2022.

Recharge and Discharge

• The main source of recharge is monsoon rain, at about 58% of annual recharge in an older count.
  • Seepage from canals, tanks, ponds and other water structures, and return flow from irrigation, account for about 32%.
  • The 2022 assessment put rain at nearly 61% of all recharge.
• Items of supply to a ground water reservoir:
  • Rain infiltrating to the water table.
  • Seepage into the aquifer from rivers, lakes and tanks.
  • Underground flow arriving from adjoining tracts.
  • Recharge from irrigation, reservoirs and artificial recharge schemes.
• Items of disposal from it:
  • Evaporation from the capillary fringe where the water table is shallow, and transpiration by plants.
  • Springs and seepage that return water to rivers, lakes and tanks.
  • Underground flow leaving for adjoining tracts.
  • Pumping, flowing wells and drains.

The Hydrological Setting

• Rock, relief and rain together decide where ground water occurs. Formations from the Archaean to the Recent control its storage and movement.
• High relief (the northern and north-eastern ranges, the Aravalli and steep Peninsular slopes) sheds rain quickly, so ground water is limited to valleys between the hills.
• The Indus–Ganga–Brahmaputra alluvium, from Punjab to Assam, is among the world’s largest and most productive ground water reservoirs. Its aquifers are thick, extensive and hydraulically connected, with moderate to high yields.
  • Along the Himalayan foot lies the Bhabar piedmont, with the Tarai below it, where water often flows out on its own.
• Peninsular hard rock gives discontinuous aquifers of limited to moderate yield.
  • The shallow weathered mantle is the key store, feeding fractures below.
  • Deeply weathered pediments, low valleys and abandoned river channels hold the better supplies, generally down to about 100 m.
  • Friable semi-consolidated sandstones give moderate yields, with some free-flowing zones.
• Coastal and deltaic tracts, and the estuaries of Gujarat, hold thick and productive alluvium, but salinity limits its use.
• Ram Lochan Singh (1971) divided India into eight ground water provinces:

Depletion and Regional Pattern

• Dependence is heavy. About 85% of rural and over 50% of urban water supply relies on ground water for drinking and domestic needs.
  • In the older count, ground water met about 80% of domestic needs nationally and 45% of all irrigation.
  • Nearly 40% of urban demand was met from it, with city water tables falling by 2–3 m a year in the older count.
  • Irrigation takes the bulk of what is drawn: about 92% in older accounts and about 87% (208.49 of 239.16 BCM) in the 2022 assessment.
• Availability by State: Uttar Pradesh had the highest net annual availability, about 72 BCM in the 2018 report, against 0.29 BCM in Delhi.
  • In 2025, Uttar Pradesh stands at 66.97 BCM extractable and Delhi at 0.35 BCM. Among States, Mizoram (0.19), Sikkim (0.22) and Goa (0.31) are lower than Delhi.
  • Punjab and Haryana show the imbalance most clearly:

• These tracts were long called dark zones, a term for heavily exploited areas. The board now uses four categories, set by the stage of extraction:

• North-west (Punjab, Haryana, Rajasthan, Delhi): low rain, plus tube wells since the Green Revolution of the 1960s.
  • A shift to rice in a climate better suited to wheat raised demand. Several districts in the two States saw levels drop more than a metre each year.
• Uttar Pradesh and Bihar: fertile tracts under intensive irrigation. Uttar Pradesh is at 70.00% and Bihar at 46.20% (2025).
• Gujarat: low rain made it lean on ground water. Its stage fell from 75% in 2009 to 55.95% in 2025.
• Tamil Nadu: long high, at 80% in 2009 and 73.50% in 2025, largely for rice.
• Peninsular hard-rock States: moderate use, with shallow, poor aquifers that fail quickly in dry years.
• North-eastern hill States: under 10% in most cases, thanks to high rain, thick forest, less intensive farming and difficult terrain. Goa has enough surface water to leave ground water lightly used (23.30% in 2025).
• Causes of scarcity differ by region:
  • Delhi, Punjab, Haryana and Uttar Pradesh: over-exploitation.
  • Rajasthan and Gujarat: arid climate.
  • Tamil Nadu, Karnataka and Andhra Pradesh: poor aquifer properties.
  • Everywhere: population pressure, industrial growth and very rapid urbanisation.
• The 2024 post-monsoon data offer a mixed sign: 54.4% of analysed wells stood higher than their previous five-year mean, while Punjab (67.2%) and Uttar Pradesh (59.1%) showed mostly falling wells.

• This map names NITI Aayog’s index and the World Resources Institute as its sources. Its bars put 2030 demand at 1,498 BCM against a supply of 744 BCM, the “twice the supply” warning repeated in the index itself.

Use, Scarcity and Quality

Water Usage

• Irrigation is by far the largest user, whichever count is taken:

• The National Commission on Integrated Water Resources Development (NCIWRD) projected that irrigation alone would need an extra 71 BCM by 2025 and 250 BCM by 2050, compared with 2010.
• This puts the main burden of saving on farming. The irrigation sector is where a small gain in efficiency frees the most water.

Water Stress and Scarcity

• Malin Falkenmark’s indicator is the usual yardstick. It rests on about 100 litres a day as the minimum for household needs and health, with some 5 to 20 times that for farming, industry and energy.

• India’s per capita availability has been falling with population, and it is now below the stress line:

• The per capita projections for 2025 and 2050 come from India-WRIS (2015), with the 2011 Census as a base. They point to India becoming water scarce.
• The national average hides extremes. A 1992 estimate gave the Brahmaputra valley 18,417 cubic metres a head, against only 411 for the small east-flowing basins south of the Pennar. The Ganga basin alone spanned 740 (Yamuna) to 3,379 (Gandak).
• NITI Aayog’s Composite Water Management Index (2018) said about 600 million people faced high to extreme stress, and about 2 lakh died each year for want of safe water. It projected demand at about twice supply by 2030, costing some 6% of GDP.
• Global context: world water scarcity comes from the same drivers. Water is finite, supplies are increasingly contaminated, and new sources cannot be tapped without end.

Drinking Water and the Burden on Women

• Findings of the National Sample Survey Office (NSSO), released in August 2014:
  • In 2012, 54% of rural women covered between 200 metres and 5 km each day for drinking water.
  • The average walk took 20 minutes, with a further 15 minutes spent waiting or drawing water at the source.
  • Every second rural woman walked an average of 173 km in the year, 25 km more than in 2008–09.
  • The same half of women gave 210 hours a year to this, which cost the household 27 days’ wages. Their combined walking equalled 64,000 earth-to-moon trips.
  • 75% of the women in Chhattisgarh, Manipur, Odisha and Jharkhand travelled long distances. Time taken was highest in Jharkhand (40 minutes), Bihar (33) and Rajasthan (30).
• 57% of rural women walked up to 5 km a day for potable water, against 21% in urban areas (NSSO).
• The water crisis in villages comes from over-harvesting of ground water, since it meets most drinking needs.
• India’s burden of water-borne disease is among the heaviest in the world, above that of some least developed nations.
• Leakage: poor maintenance and leaky mains waste about a third of supply in most big cities before it reaches a tap. The Centre for Science and Environment counted losses above 35% for Delhi and near 30% for Mumbai.
• Urban supply gaps: the World Health Organization’s minimum of 100–200 litres a day is well above the urban average of about 90 litres.
  • A 2005 survey by the Tata Institute of Social Sciences counted lakhs of water-deficient households in the big cities: Mumbai 17.36 lakh, Delhi 14.73 lakh, Kolkata 4.37 lakh, Ahmedabad 4.29 lakh, Hyderabad 4.14 lakh, Kanpur 3.30 lakh and Madurai 1.49 lakh.

• Access in the 2011 Census: 85.5% of households had safe drinking water by tap, hand pump or tube well (urban 91.4%, rural 82.7%).
  • Highest and lowest: Punjab 97.6% and Meghalaya 44.7%; among Union Territories, Chandigarh 99.3% and Lakshadweep 22.8%.

How Safe Is Our Water

• About 70% of surface water in India is polluted, and NITI Aayog cited the same share of water as contaminated in 2018.
• Main contributors: wastewater from many sources, intensive agriculture, industrial production, infrastructure development and untreated urban runoff.
• The Ganga: about 2.9 billion litres of waste water reach the river every day from industry and homes.
  • A 2016 estimate put this at 2,953 million litres a day from 97 towns, against a treatment capacity then of 1,584, so a large part was going in untreated. Capacity has since grown under Namami Gange.
• By the estimate of the World Health Organization (WHO), half of India’s morbidity is water related.
• Waste management has not kept pace with the volume generated, especially in cities.
  • Municipal treatment capacity once covered only 29% of waste from urban habitations above 50,000 people.
  • National capacity in a later count stands at 31,841 million litres a day against 72,368 generated, about 44%.
  • More than 70% of untreated domestic effluent reaches the environment, so households are a major part of the pollution load. Control rests on the Water Act of 1974.

• These counts date from about 2015–16. Later national monitoring describes ground water as largely potable, with fluoride, arsenic and nitrate in localised pockets.

The Costs of Unsafe Water

• Worldwide, in the counts of the time:
  • 2.2 billion people had no access to clean water at home. In 2024 the figure for safely managed drinking water stood at 2.1 billion.
  • 2.3 billion people lacked basic sanitation such as toilets or latrines. In 2024, 3.4 billion lacked safely managed sanitation.
  • More than 800 children under five died every day from diarrhoea caused by dirty water.
  • 700 million people could be displaced by intense water scarcity by 2030.

Water Access in Rural Areas

• More people in rural India had phones than safe drinking water in the mid-2010s.
  • Only 18% of the 833 million rural population had treated water, while 41%, or 346 million, owned mobile phones (Forbes India, 2015).
  • 30% of rural Indians lacked a drinking water supply (World Bank, UNICEF).
• Jal Jeevan Mission has since changed the picture. Tap connections rose from about 3.23 crore rural households (17%) in 2019 to about 15.80 crore (81.61%) of 19.36 crore by March 2026. The Union Cabinet extended the mission to December 2028.

• This chart shows rural households in the 2011 Census, before the tap water mission, and its State figures are the share travelling more than 0.5 km.

Climate Change and Water

• The IPCC’s Fifth Assessment Report (AR5) said mean annual temperature is rising all over Asia, and projected a rise of more than 2°C by the end of the 21st century.
• Warming melts glaciers, and their retreat affects the water available in Himalayan rivers.
  • An often quoted figure says almost 67% of Himalayan glaciers retreated in a decade.
  • ICIMOD (2023) found glaciers of the Hindu Kush Himalaya lost ice up to 65% faster in the 2010s than in the decade before, and would lose 30–50% of their volume by 2100 at 1.5–2°C of warming.

Water Footprint

• A water footprint counts the virtual water used to make a product, all along its chain of production.
• In older counts, chocolate (24,000 litres per kg) and leather (17,000) ranked highest, followed by sheep (10,400), cotton (10,000), butter (5,550) and chicken (4,330).
  • Later counts put chocolate nearer 17,000 litres per kg.
  • Fruits and vegetables have the lowest virtual water footprints.

Water Disputes and Shared Rivers

• A resource in short supply breeds conflict. Almost all major Indian rivers are shared by States, and many basins are shared with neighbours.
• Inter-state water disputes have arisen over the Cauvery, Krishna, Tungabhadra, Aliyar and Bhavani, Godavari, Narmada, Mahi, Ravi and Beas, Satluj–Yamuna Link, Yamuna, Karmanasa and Barak.
  • They are settled by negotiation on the basis of equitable apportionment, or by tribunals under the Inter-State River Water Disputes Act, 1956. By February 2026, nine tribunals had been constituted, and five had reported.
• Cooperation with neighbours runs through treaties and joint bodies:

Conservation of Water

Saving Water in Use

• Water is a cyclic resource: it can be cleaned and used again. Careful use is the best way to conserve it.
• Irrigation:
  • Over-irrigation has caused waterlogging in western Uttar Pradesh, Punjab, Haryana and the Hirakud command, and saline and alkaline tracts in arid areas.
  • Over-draft by tube wells has lowered water tables in Haryana, Punjab and western Uttar Pradesh.
  • Canal lining checks seepage. Drip and sprinkler systems save about 30–60% of water. They once covered only 0.5% and 0.7% of the irrigated area respectively, nearly half of the drip in Maharashtra.
  • Treat each river basin as one planning unit, and practise dry farming in dry areas, helped by the watershed programme for rainfed farming running since 1986–87.
• Industry: most industrial water is for cooling, which does not need potable supply. Recycling leaves more for other sectors and reduces effluents.
• Homes: a standard flush uses about 12.5 litres, while small cisterns use 5–7 litres.
  • Raw water can serve for cleaning and gardening.
  • Water from kitchen sinks, wash basins and bathrooms can be collected to flush toilets and water gardens.
• Recycling and desalination remain options, though at high cost. A UN resolution of 1992 set aside 22 March as World Water Day.

Rainwater Harvesting

• Rainwater harvesting collects and stores rain at the surface or in aquifers before it runs off, for people, animals and plants.
  • Artificial recharge adds to ground water at a rate above natural replenishment.
• Why it is needed: surface water falls short of demand, and water levels are falling. It makes ground water available at a chosen place and time.
  • It also restores infiltration lost to paving in cities, dilutes pollutants, supports farm output and improves vegetation.
• Advantages:
  • Recharge costs less than building surface reservoirs, and the aquifer doubles as a distribution system.
  • No land is lost and no one is displaced.
  • Stored water is not exposed to evaporation and pollution.
  • It raises aquifer productivity and water levels, reduces flood hazard and soil erosion, and eases drought.
• Where it is most needed: falling water levels, desaturated aquifers, shortage in lean months and urban tracts with reduced infiltration.
• The Centre for Science and Environment estimated that harvesting from just 2% of India’s land would yield 26 gallons a head.
• Roof-top yield is simply rainfall times roof area, with a runoff coefficient of 0.8. A 100 sq m roof under 1,000 mm of rain gives 80 cubic metres, and a 50 sq m roof under 600 mm gives 24 cubic metres.

Urban Methods

• All these share three safeguards: a roof mesh against leaves and debris, a desilting chamber at ground level and a by-pass to reject the first showers.
• For aquifers below about 20 m, the recharge well sits inside a shallow shaft 2–5 m across.

Rural Methods

• In rural areas the watershed is the unit. Land is plentiful, so surface spreading is common and the recharge large.

National Schemes

• Jal Shakti Abhiyan (2019): a time-bound, mission-mode campaign, first in 256 water-stressed districts.
  • Jal Shakti Abhiyan: Catch the Rain extended it across India in 2021, with the tagline “Catch the rain, where it falls, when it falls”. The sixth edition began on 22 March 2025.
  • About 1.21 crore water conservation and recharge works were completed in the four years to late 2025, through convergence of existing schemes.
• Jal Sanchay Jan Bhagidari (6 September 2024): community building of low-cost harvesting structures.
• Atal Bhujal Yojana: community-led ground water management in 80 water-stressed districts of 7 States (Gujarat, Haryana, Karnataka, Madhya Pradesh, Maharashtra, Rajasthan and Uttar Pradesh).
  • It created more than 83,000 recharge and harvesting structures, and brought more than 9 lakh hectares under efficient irrigation.
• Mission Amrit Sarovar: at least 75 water bodies in each district, with nearly 69,000 built or rejuvenated.
• National Aquifer Mapping (NAQUIM): about 25 lakh sq km of mappable area covered, across 14 principal and 42 major aquifers, with management plans for 654 districts.
• Master Plan for Artificial Recharge (2020): about 1.42 crore structures that could harness about 185 BCM.
• Central Ground Water Authority: regulates extraction under pan-India guidelines of 24 September 2020, through no-objection certificates, charges and curbs on new large industries in over-exploited areas.
• Jal Jeevan Mission: the drinking water programme described above.