Fresh guidelines issued for rainwater harvesting in Delhi, NGT told

The NGT has been hearing a case since February 2023, after a Dwarka resident alleged that RWH pits in the sub-city were polluting groundwater

The Delhi Jal Board (DJB) has issued fresh guidelines for rainwater harvesting (RWH) in the Capital, warning that new pits should not be built near stormwater drains to prevent groundwater contamination.

In its latest submission on August 21, DJB said the July 31 committee decided to focus on upcoming pits to prevent further contamination. (Representational image)

In an affidavit to the National Green Tribunal (NGT) WHEN, DJB said a joint expert committee met on July 31 to examine contamination risks linked to RWH structures. The panel recommended that separators be installed to divert the “first flush” of rainwater from entering pits and contaminating aquifers.

The NGT has been hearing a case since February 2023, after a Dwarka resident alleged that RWH pits in the sub-city were polluting groundwater.

A joint inspection in May 2023, involving DJB and Delhi Pollution Control Committee (DPCC) officials, found pits at 235 societies in Dwarka. Of these, 180 had high ammoniacal nitrogen and dissolved solids. A follow-up inspection in March 2024 reported faecal coliform in 115 societies, while four societies had non-functional pits.

In its latest submission on August 21, DJB said the July 31 committee decided to focus on upcoming pits to prevent further contamination. “It is to be ensured that no RWH structure comes up in stormwater drain areas. Further, a separator is required to bypass the first rain from entering into the RWH structure,” the report said.

The committee also discussed the use of piezometers, devices that track groundwater levels. Instead of requiring each site to install one, it recommended a single piezometer for every 5 sq km, noting that the DJB has already set up 95 such devices near sewage treatment plants to monitor recharge.