As India’s metros grapple with water scarcity, one Bengaluru resident has quietly found a way to make every drop count. Prabhat Vijayan, a 45-year-old tech manager living in Horamavu, built a DIY setup to collect and reuse reverse osmosis (RO) wastewater, saving his household nearly 24,000 litres of water every year.
In a city where borewells are drying and water tankers charge up to Rs 1,000, Prabhat’s model offers a simple, cost-effective path to conservation — one that any urban resident can replicate.
What Is RO Wastewater and Why Is It Wasted?
Most homes today rely on RO purifiers for drinking water. While they effectively remove impurities, they also discard a lot of water — typically four litres of wastewater for every litre of purified water.
This “waste” water isn’t contaminated — it’s simply high in minerals and unsuitable for drinking but perfectly usable for household chores like cleaning, flushing, and watering plants.
From Concern to Action: The Origin of the DIY Setup
Originally from Alleppey, Kerala, Prabhat was used to an abundance of clean water. But when he moved to Bengaluru in 2014, things changed.
“We rely on borewells and expensive tanker water. It made me realise how precious water really is,” he says.
He noticed his RO system constantly draining water and decided to take matters into his own hands. With a few tools and a Rs 500 drum, he built a water-saving system right in his apartment.
Step-by-Step: How Prabhat Built His RO Water-Saving System
You don’t need to be an engineer or plumber to do this. Prabhat’s process is straightforward, affordable, and space-friendly:
1. Get a Collection Drum
- He used a 50-litre plastic drum, easily available for Rs 300–500.
- Place it in a 2-square-foot corner of your kitchen, utility area, or balcony.
2. Connect the RO Pipe
- Using a screwdriver, drill a small hole in the drum lid.
- Insert the RO waste discharge pipe into the hole.
3. Store and Use the Water Smartly
The water collected is reused for:
- Mopping floors
- Flushing toilets
- Washing the car
- First rinse of utensils
- Watering plants and garden use
Savings That Add Up
Over the years, Prabhat has saved over 40 water tankers using this method — equivalent to Rs 40,000 or more in water bills.
“Now, the water hardness in our area is 800 ppm. The water table has dropped below 1,000 feet. We can’t wait for a crisis to act,” he says.