Delhi economic survey: Water supply-demand gap cut with tweak in usage estimates

The 2025-26 economic survey states that the Delhi Jal Board now estimates the city’s water demand to be 1,250MGD, leaving a demand-supply gap of 250MGD.

Delhi’s daily water supply has remained unchanged at about 1,000MGD (million gallons daily) for the past three years, but the city’s demand-supply gap in potable water has reduced on paper, with authorities progressively lowering per capita water requirement estimates, according to the latest economic survey.

For future planned developments, potable water supply is proposed to be restricted to 40GPCD. (Representational Image)

The 2025-26 economic survey states that the Delhi Jal Board now estimates the city’s water demand to be 1,250MGD, leaving a demand-supply gap of 250MGD.

The calculation is based on a revised benchmark of 50 gallons per capita per day (GPCD) for a projected population of 25 million. The estimate excludes water required for horticulture, agriculture and industrial use.

This marks a shift from earlier assessments. The previous economic survey had pegged demand using a norm of 60GPCD, estimating the city’s requirement at 1,290MGD in 2023-24 and 1,380MGD in 2021–22, with varying population projections. The government did not table an economic survey in 2024–25.

The DJB has indicated that this downward revision will continue. For future planned developments, potable water supply is proposed to be restricted to 40GPCD, reflecting a policy shift towards demand-side management amid limited raw water availability.

The math of water supply in Delhi. (HT)

“Given the limited availability of raw water to Delhi, water demand of potable water for domestic use needs to be rationalised and progressively reduced to 50GPCD by using non-potable recycled water of desired quality standard for non-drinking purposes such as toilet flushing, etc. Water demand for industrial process & horticulture/gardening/agriculture purposes will need to be necessarily met out from recycling of waste water of desired quality standards,” the report states.

It projects that for a population of 30 million by 2041, potable water demand, calculated at 50GPCD, would be 1,500MGD. “For future planned developments, availability of potable water is proposed to be restricted to 40GPCD,” the report further said.

Under this framework, residential consumption is pegged at 135 litres per capita per day (LPCD), non-residential use at 20LPCD (including 5LPCD for floating population), fire demand at 2LPCD, and transmission losses at around 15% (23LPCD).

“Water requirement for toilet flushing purposes in residential developments and non-residential developments (about 75PCD) shall have to be met by use of non-potable recycled water of desired quality standard with dual piping system. Water demand for industrial process & horticulture/gardening/agriculture purposes shall also need to be necessarily met out from recycling of waste water of desired quality standard,” the report states.

Delhi’s total water supply has remained largely static at about 1,000MGD across 2024, 2025 and 2026. This includes 612.5MGD from the Yamuna, DSB and CLC canals, 254.08MGD from the Ganga, and around 135MGD from groundwater sources such as tubewells and Ranney wells. The city remains heavily dependent on neighbouring states for raw water.

To bridge the gap, DJB plans to augment groundwater extraction and blend it with surface water to meet drinking standards, citing pollution in raw water sources at Wazirabad.