For years, the little white pipe from the RO was bothering me a lot.

Every time I used our RO purifier, two or three glasses of water went straight down the drain. Here is how I started collecting and reusing that RO waste water at home.

I felt guilty every time I stood at that sink. I also did nothing about it for months. Feeling guilty, it turns out, is much easier than fixing things. 🙈

Why does the purifier waste water?

RO stands for reverse osmosis. The purifier pushes water through a very fine filter, called a membrane. Water passes through, but the dissolved salts stay behind. Those salts have to go somewhere. So the purifier washes them away with extra water, and that is what comes out of the little pipe.

So the “waste” water is not dirty. It is just saltier than the water that went in. Not good for drinking, but perfectly fine for many other jobs.

My purifier wastes 2 to 3 litres for every litre it gives us. That sounds small, until you do the maths. Say if my family uses 20 litres of purified water a day. That is 40 to 60 litres down the drain, every day. Over a year, it adds up to 14,000 to 22,000 litres. That is about three to four full water tankers, from one home.

How I Started Reusing RO Waste Water

Attempt one: a bucket

About six months ago, I finally acted. I put the pipe into a bucket and walked away feeling like a very responsible citizen. It lasted two days. The bucket filled faster than I expected, and I kept checking it, emptying it and carrying it around the house.

That taught me something: if saving water feels like hard work, nobody keeps doing it.

Attempt two: let the tank do the work

So I bought a 30-litre AquaSave tank and connected the purifier’s waste pipe straight into it. Now the water collects on its own.

No checking, no carrying, no wet floor. And once the water was simply there, ready to use, the family started using it without being told:

• Floors do not need filtered water.
• Cleaning oily plates before the final wash.
• Watering the plants on the balcony

Can RO Waste Water Be Used for Plants?

The plants have no complaints

Many people say RO waste water is bad for plants because of the salts. I was curious, so I tried it anyway. After six months, our pots are still green and full of fresh flowers. Honestly, the plants are the only members of the house who never complain. 🌱

One small caution: our water suits our plants, but yours may be harder. A TDS meter will tell you how salty it is. If you see a white crust on the soil or brown leaf tips, mix in some normal tap water and give the pots a good flush now and then.

And one tip before you buy a purifier at all: if your tap water already has low salts, you may not need RO. Newer purifiers also waste much less water. The best water to save is the water you never waste.

Start small

We often think living sustainably needs something big, like expensive setups or a whole new lifestyle. That feels like too much, so we end up doing nothing.

For me, it was one pipe, one tank, and a decision to stop staring at the drain.

The little white pipe still runs every day. It just does not run into the drain anymore. 😊