DJB Attributes Rainwater Harvesting Pit Contamination to Poor Maintenance by Dwarka Societies
In a significant development, the Delhi Jal Board (DJB) has informed the National Green Tribunal (NGT) that the widespread contamination detected in rainwater harvesting (RWH) pits across Dwarka is primarily due to inadequate upkeep by group housing societies, rather than any inherent flaw in its prescribed technical design. This submission comes in response to tests conducted last year, which revealed alarming levels of E. coli and faecal coliform in the pits, raising serious concerns about groundwater pollution in the area.
Test Results and Inspection Findings
According to the DJB's reply submitted on January 5, inspections were carried out during the monsoon season, which is considered the most suitable period to assess the performance of rainwater harvesting systems. The board reported that out of 144 societies examined, faecal coliform was detected in the pits of 124 societies. Additionally, eight pits were found to be completely dry, repairs were underway in seven societies, two systems were non-functional, and three societies did not permit sampling. These findings highlight a critical issue in the maintenance and operation of RWH infrastructure.
Impact on Adequacy Certificates and Rebates
The presence of faecal coliform in the harvesting pits has a direct consequence on the issuance of adequacy certificates, which are essential for housing societies to avail a 10% rebate on their water bills. DJB emphasized that these certificates are only granted to functional systems that meet the required standards. By failing to maintain their pits properly, societies are not only jeopardizing groundwater quality but also losing out on financial incentives designed to promote sustainable water management practices.
DJB's Defense of Technical Design and Compliance
In its response, DJB strongly refuted allegations that its technical design for rainwater harvesting pits is inadequate. The board maintained that key components, such as overflow pipes and first-flush separators, are mandatory under NGT directions and national guidelines. These elements are crucial for preventing flooding, backflow, and the entry of pollutants into the harvesting pits. DJB argued that relaxing these provisions would violate established norms and undermine the effectiveness of the systems.
Furthermore, the board denied any negligence on its part, asserting that it continues to comply with the norms set by the NGT and the Jal Shakti ministry. This stance is part of an ongoing hearing before the tribunal, which was initiated by a plea filed in 2023 by a Dwarka resident alleging groundwater contamination due to faulty RWH pits.
Broader Implications for Water Management in Delhi
The case underscores the challenges in implementing and maintaining rainwater harvesting systems in urban areas like Dwarka. While the technology is designed to enhance water conservation and reduce reliance on groundwater, its success heavily depends on proper maintenance by end-users. The DJB's submission highlights the need for stricter oversight and accountability from housing societies to ensure that these systems function as intended, protecting both public health and the environment.
As the NGT continues to hear the matter, the outcome could set a precedent for how rainwater harvesting initiatives are managed across Delhi and other metropolitan regions, emphasizing the importance of collaborative efforts between authorities and residents in achieving sustainable water solutions.
