Needed: A practical way to save and reuse the RO run off water

Most of us are familiar with the Reverse Osmosis (RO) water purifier technology that has been around for a few years now, even if not using it. While it seems to be widely accepted that RO-based purifiers are suitable for water supplies having high TDS (Total Dissolved Solids) content, debates have been on about the effects on our health due to the demineralized water that we consume after the RO-purification.

Demineralisation aside, I would like to turn to one glaring feature of this technology in its current form: water runoff–that is, the non-potable water that an RO-purifier generates during the process of purification. It is said that three liters of water runs off as ‘waste’ from the purifier for every liter of ‘pure’ water it produces (3:1).

The purifier brands normally recommend saving of runoff water for reuse such as gardening, cleaning floors, washing clothes/vehicles, etc. Surely that is the least an eco-conscious person using an RO would do. But the matter is about the practicality of saving the runoff water. Today, all that a purifier offers is a tube running out of it, which we need to take it to an external storage such as a bucket or drum kept a level lower than the purifier unit itself.

Then the runoff water so collected is shifted to the garden or washroom or garage for reuse. Though not sounding a big deal, it certainly is a chore added, especially for those who have enough chores already or are physically unable to move the water-filled containers around the home. In such case, the runoff water is often let go into the kitchen sink. Imagine in such a case the amount of runoff water that would be wasted! (In some European countries, even wastewater let out from a domicile is metered and billed!)

To me, it struck as a simple practical issue and solving it will not only bring a big relief to the homemakers but also incentivise to save the large quantity runoff water. Can’t we have a simple, effective and elegant solution to save the runoff water? What is it that is essentially needed? All that is mainly needed is a fairly automatic mechanism to:

  1. Collect the runoff water from the purifier in an appropriately sized and placed container.
  2. Economically pump (e.g. using solar pumps) the collected water further – either to an overhead tank or a sump or the like for reuse.

Alternatively, apartments or houses can even install a permanent and dedicated piping that can lead the runoff water coming from the purifier directly to some storage outside the kitchen.

Perhaps there are better ideas. Whichever the final solution, it must to be effective and it must to be economical.

At present, most of our focus goes into obtaining good quality potable water. If we also start sensitising on how to achieve the same with minimal wastage, it will help save the very precious resource we are trying to purify!

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  1. even the plants and vegetation have to served with good qlty of water which contain certain minerals and eletrolytes. they will die if they receive the reject water from RO.Also unsuitable for washing cloth. there will be no lather formation. may be ok to car cleaning or using to flushing toilets

  2. Yeah,it is very disheartening to see so much water going down.So, what I do is collect it in a large vessel and use it for washing veggies etc (it is more pure than tap water !) and also pour it in a bucket for mopping or to wash feet in the bathroom. Could save atleast 50% of the water. Connecting to garden would be best, but difficult.

  3. This is an issue I too have been dealing with. It is a shame to see a large amount of water literally going “down the drain” especially during these times when water is becoming a scarce resource.
    I usually turn on the RO filter only once early in the morning as usually one “tank-full” suffices for our small family for the day. The outlet leads to the washing machine and is used to wash clothes. Every morning I fill a few bottles and water jugs which along with the filter tank fulfills our daily drinking water needs.
    I am not sure if the water is good enough to wash clothes or there are other negatives in this practice. Will welcome your feedback.

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