In a major push toward groundwater conservation and sustainable water management, the Delhi Government is preparing a new policy to expand the use of treated sewage water in construction projects, park irrigation, and other non-potable activities across the national capital.
Officials said the proposed framework is being developed by the Delhi Jal Board (DJB) to ensure that treated wastewater generated from sewage treatment plants (STPs) is used more efficiently in sectors where drinking-quality water is not required.
Delhi Public Works and Water Minister Parvesh Sahib Singh said the policy aims to reduce pressure on rapidly depleting groundwater reserves while promoting sustainable urban water reuse practices.
Treated water already used for horticulture
At present, treated water from STPs operated by the DJB and the Delhi Development Authority (DDA) is already being supplied for horticulture and landscaping activities.
According to officials, around 89 million gallons per day (MGD) of treated water is currently distributed for non-potable use to agencies including the Central Public Works Department (CPWD), New Delhi Municipal Council (NDMC), DDA, and the Municipal Corporation of Delhi (MCD).
However, the government now plans to significantly increase its usage, particularly in construction works carried out by government agencies. Officials added that supplying treated water to private construction firms at affordable rates may also be considered in later phases.
Focus on construction and park irrigation
The proposed policy is expected to prioritise the use of treated wastewater in construction activities, where large quantities of freshwater are currently consumed.
Officials noted that technical standards will play an important role in implementation. Guidelines issued by the Bureau of Indian Standards specify that water used for construction should maintain a pH level between 6 and 8.5, while total dissolved solids (TDS) should remain below 2,000 parts per million.
Authorities warned that poor-quality water can weaken concrete structures and damage iron components, making proper treatment and monitoring essential.
In addition to construction, the government is also planning to expand treated water supply for irrigation of parks, gardens, green belts, and residential welfare association-maintained open spaces through dedicated pipelines connected to STPs.
Officials said decentralised sewage treatment plants may also be installed near parks to locally recycle domestic wastewater for horticulture use.
Delhi facing severe groundwater stress
The move comes amid growing concerns over groundwater depletion in Delhi.
A 2024 report by the Central Ground Water Board revealed that the city is extracting groundwater at a rate higher than its natural recharge capacity.
Out of Delhi’s 34 assessed tehsils, 14 were classified as “over-exploited,” 13 as “critical,” two as “semi-critical,” and only five were categorised as “safe.”
Officials said the safe reuse of treated wastewater is increasingly being viewed as a national priority as cities struggle with rising population pressure and declining freshwater availability.
Expansion of treated water infrastructure
Delhi currently generates nearly 530 MGD of treated water through its sewage treatment plants. However, only around 105 MGD is presently utilised, mainly for roadside plantations, green areas, and lake restoration projects.
To improve distribution infrastructure, the Delhi Jal Board has already approved a ₹90-crore project aimed at transporting treated water from STPs for horticultural use across the city.
Officials said the upcoming policy could also explore additional applications for treated wastewater, including firefighting and other urban utility services, as Delhi moves toward a more sustainable and circular water management system.