Delhi govt mulls policy to scale up treated water use

Delhi plans to boost treated water use for non-potable needs like construction and firefighting to combat groundwater depletion, aiming for sustainable management.

New Delhi

Authorities, however, said technical standards would need to be carefully adhered to before treated water can be widely deployed. (Representative photo)

The Delhi government is preparing a policy to scale up the use of treated water for non-potable purposes, such as construction, firefighting and horticulture, amid mounting pressure over depleting groundwater reserves, officials aware of the matter said on Friday.

The Delhi Jal Board (DJB), which will formulate the policy, is seeking to reuse treated wastewater generated at sewage treatment plants (STPs) and reduce dependence on freshwater and groundwater resources.

DJB minister Parvesh Verma said, “We are assessing all purposes for which treated water can be used. Some Public Works Department (PWD) projects are already using treated water. We have also started using it at a park in east Delhi as a pilot. Some residents welfare associations (RWAs) also approached us for supply of treated water, citing separate tanks used only for flushing.”

Officials said that while treated water is already being extensively used for horticulture and landscaping, the government wants to institutionalise and expand its use in construction works undertaken by public agencies, and is also exploring the possibility of supplying it to private builders at affordable rates.

Officials said the policy would prioritise the use of treated water in government construction projects, especially for curing concrete, dust suppression and landscaping. The government is also exploring its use for firefighting and other urban utilities.

An official aware of the developments, requesting anonymity, said, “A meeting is likely to be held with the fire department soon to explore the possibility of using treated water for fire tenders. As of now, several litres of clean water used by fire tenders can be replaced with treated water.”

Authorities, however, said technical standards would need to be carefully adhered to before treated water can be widely deployed. Bureau of Indian Standards (BIS) guidelines prescribe that water used for construction should have a pH value between 6 and 8.5, while total dissolved solids (TDS) should not exceed 2,000 parts per million (ppm).

“Poor quality water can adversely affect the strength of concrete and lead to corrosion in iron structures,” the official said, adding that quality monitoring mechanisms would form an important part of the proposed framework.

The policy also seeks to expand the supply of treated water for irrigation of parks and green belts maintained by government departments and resident welfare associations (RWAs). Officials said pipelines could be laid from nearby STPs to major parks, while decentralised sewage treatment systems may also be developed near residential colonies and green spaces.

The move comes amid worsening groundwater stress in the national capital. According to a 2024 report by the Central Ground Water Board (CGWB), Delhi continues to extract groundwater at a rate higher than its natural recharge. Of the city’s 34 assessed tehsils, 14 have been categorised “overexploited”, 13 as “critical”, two as “semi-critical” and only five as “safe”.

Officials said Delhi’s STPs currently generate nearly 530mgd of treated water every day, but only around 105mgd is being utilised. Most of the remaining treated water is discharged despite being suitable for non-potable applications.

The push also aligns with the Centre’s broader “Safe Reuse of Treated Water” (SRTW) framework, which is being promoted across states as part of sustainable urban water management. Uttarakhand has already notified a policy encouraging reuse of treated wastewater for construction, industrial processes, irrigation, flushing and urban landscaping.

In a related move, the DJB recently approved a ₹90-crore project to develop infrastructure for transporting treated water from STPs for horticulture purposes across Delhi.