Currently, there are 357 rainwater harvesting pits in NDMC areas, with 273 constructed by the road division and 84 by the building department. Chahal noted that some of the existing pits incorporate modular rainwater harvesting (RWH) systems. Based on their success, the NDMC decided to replicate the concept. He also mentioned that assistance from the Jal Shakti Ministry might be sought if necessary. The identified locations for these pits are expected to address waterlogging issues while enhancing rainwater conservation.

The proposed sites for the pits include Janpath Road, Ashoka Road, Jaswant Singh Road, Jantar Mantar Road, Hanuman Road Park, Vakil Lane, Balwant Rai Mehta Lane, Copernicus Lane, Bhagwan Das Road, Pandara Park, Subramaniam Bharti Marg, Kaka Nagar, and Bapa Nagar.

The modular system utilizes pre-fabricated polymer-based blocks configured in an interlocked arrangement around a borewell pipe, which is 30–35 meters deep to facilitate efficient water percolation. An official described the system’s operation, stating that it comprises three chambers, all underground except for the covers of the drain and filter chambers.

Rainwater collected from stormwater drains is directed into underground brick masonry manholes. From the manhole, a pipe leads to the second chamber, which serves as a filter unit. This chamber contains a strainer to trap dirt, silt, and solid debris, allowing only filtered water to pass into a steel bucket installed at the bottom. A pipeline connects the filter unit to the third chamber, made of polymer-based blocks arranged in an interlocked position. The entire system is wrapped in geotextile fabric to prevent soil intrusion.

The structure enables rainwater to seep into the borewell pipe through perforations while providing additional water storage capacity. Its design also allows the surface area above to be used for purposes such as vehicle parking.