The Water Purification System (Regulation of Use) Rules, 2023 provides guidelines for managing, storing, and utilizing RO reject water and discarded elements from these systems.

 RO reject water in India is covered by regulations and laws. The Ministry of Environment, Forest and Climate Change (MoEF&CC) has established guidelines for its proper management, storage, and utilization through the Water Purification System (Regulation of Use) Rules, 2023. These rules, which came into effect on November 10, 2024, are part of the broader legal framework for water management and pollution control. Additionally, the National Green Tribunal (NGT) has also played a role in shaping regulations around RO water purification. 

Here's a more detailed breakdown:

1. Regulations for RO Reject Water:

The Water Purification System (Regulation of Use) Rules, 2023 provides guidelines for managing, storing, and utilizing RO reject water and discarded elements from these systems.

These rules, effective from November 10, 2024, address the proper disposal and reuse of RO reject water.

The Bureau of Indian Standards (BIS) also has standards for RO systems, including the "IS 16240: 2023 Reverse Osmosis based point of Use Water Treatment System for Drinking Purposes - Specification (First Revision)". 

2. NGT's Role in Shaping Regulations:

The NGT has issued guidelines to restrict RO water purifier use where Total Dissolved Solids (TDS) levels are below 500 ppm.

This restriction aims to prevent unnecessary water wastage and mineral depletion when RO filtration is not needed. 

3. Impact of Regulations:

These regulations ensure that RO reject water is managed in a responsible manner, minimizing environmental impact.

They also encourage the proper use of RO systems and discourage their unnecessary deployment when TDS levels are low.

These regulations provide a framework for ensuring that RO systems are used effectively and sustainably. 

4. Examples of Reuse:

RO reject water can be reused for various purposes, including cleaning, washing cars, and watering plants. 

It can also be used in the production of cement bricks, according to ihs.org.in. 

In essence, RO reject water in India is not simply a waste product but a resource that must be managed responsibly. The regulations and laws in place aim to ensure its proper disposal and reuse, minimizing environmental impact and promoting sustainable water management