Top 6 Innovative Ways to Reuse the Waste Water from RO Water Purifiers
Most Indian homes use RO water purifiers, but very few know about the side effects of using one.
This isn’t surprising. RO water purifiers provide reliable water purification, but they often lead to unnecessary wastage of water.
Should you stop using RO water purifiers?
OR
Should you stop worrying about the wastage of water?
Out of all the water purifier technologies, RO water purification is the most reliable. And if your home/office has high TDS water then you have no choice but to use an RO water purifier.
What if we tell you something that lets you enjoy trustworthy RO purification without having to worry about the wastage of water?
You just need to know about some easy ways to reuse RO waste water, and then take action.
In this guide, we’ll go through six actionable ways to reuse RO waste/reject water to reduce water wastage.
But first, let’s go over the basics.
Why Re-Use RO Waste Water?
Using RO water purifiers not only gives us safe, clean, and tasty water but also protects us from life-threatening waterborne diseases.
But there is one big drawback of using RO water purifiers i.e. the excessive wastage of water. An average RO purifier wastes approximately 3 litres of water for every 1 litre of purified water. That means only 25% of water is purified and 75% of water comes out as waste.
Wondering why so much water is wasted? Reverse Osmosis (RO) purifiers use membrane technology to filter dissolved impurities, the impure water is filtered out and is often called wastewater or reject water. The percentage of wastewater varies according to the RO purifier being used.
However, RO waste water can be used in various ways to avoid the overall wastage of water in your home or office.
Before we check out how you can use this waste water, let’s look at some things to be kept in mind beforehand.
Things to Keep in Mind Before Using the RO Waste Water
It is best to determine the TDS level in the rejected water before deciding to reuse it for other purposes.
To be 100% sure, if possible, the waste water should also be tested for the presence of inorganic and chemical impurities like Sodium.
In addition to the TDS level, a few websites and several videos on YouTube also suggest checking the pH value of the RO reject water. However, there would hardly be any difference in the pH value of the input water and the RO reject water. So you need not worry about the pH value of the Reverse Osmosis waste water.
Click to read: Why You Must Not Use RO Water in Battery?
How to Store the RO Waste Water?
The easiest way would be to drop the reject pipe in a bucket. But if your daily drinking water requirement is 20 litres then on average your RO water purifier would generate around 60 litres of wastewater.
Assuming you are using a bucket of 15 litres, you would need to empty the bucket 4 times a day. And the biggest pain is keeping a check on the bucket, so it does not overflow.
This may not be practical for a lot of users.
If you are one of those then worry not because we have a better solution for people like you.
You can extend the RO waste pipe and drop it in a big tank placed outside your kitchen. This stored water can later be re-used in one of the several ways listed below.
You can use a small submersible pump (like the ones used in water coolers) to take water from this tank. All you have to do is drop the submersible pump in the tank and connect it to a power source.
You can then use a water pipe connected to the outlet of the pump to draw water from the tank without using any bucket or container. A bigger tank also means that you do not have to worry about water overflow, as would be the case if you were using a bucket in place of a big tank.
The bucket, container, or tank used for storing Reverse Osmosis waste water should have a wide opening so you can easily clean the deposits at regular intervals.
6 Easy Ways to Re-use RO Reject Water
1. Wash Your Car
A single car wash could consume anywhere between 14 litres (for a car wash using a bucket) to 75 litres (for a car wash using a hosepipe) of water. Keeping in mind the scarcity of drinking water, using so much potable water for a car wash seems unreasonable and no less than a crime.
We believe, washing cars every day not only wastes a lot of water but is unnecessary. If you are using an RO water purifier at your home or office then you can simply store the wastewater in some tank or bucket and reuse it for washing your car. Water with a TDS level of 1200 – 1500 PPM can be safely used for car washing. If the TDS level of waste water is high you can mix tap water to dilute it. This should lower the TDS level.
2. Watering Your Plants or Home Garden
If you are someone who loves gardening or have planted some plants in pots, the wastewater can be used for watering your plants to keep your indoor or terrace garden green. This tip is particularly useful for people living in urban areas as the TDS level in municipal water tends to be lower.
To be on the safer side, you can start with a few plants. Use the RO waste water for 15-20 days and check its effect on the growth of your plants. Each plant will respond to this change differently, which will give you a clear understanding of which plants are responding better to RO waste water. For gardening/irrigation use, a TDS level of up to 2100 PPM is permissible. You should also check out the percentage of Sodium, it should be less than 60 % ( 1.e. Na / Na + Ca + Mg). High Sodium content causes loss of soil porosity and therefore harmful to soil fertility in the long run.
3. Wash Your Utensils
Another useful application for Reverse Osmosis waste water is to wash your utensils. Simply store the wastewater in a bucket or tank, make sure you place the bucket for collecting RO waste water near your kitchen sink so it can be used easily when you clean your utensils.
We found this useful YouTube video that shows you how you can easily reuse the RO waste water in your kitchen for washing utensils.
4. Floor Mopping
Using the RO waste water for mopping the floor is easy and will save tens of litres of clean water every day. If you have a bigger house then the savings could be in hundreds of litres every single day. If the TDS level of waste water is high (over 2000 ppm):
- Dilute waste RO water with an equal quantity of tap water. Because plain Reverse Osmosis waste water with high TDS may stain or leave salt particles on the floor.
- Use the RO waste water for floor mopping on alternate days. This will reduce the chances of any stains or salt deposits.
5. Pre-rinsing Laundry
You can use the RO waste water for daily laundry as well, but please keep in mind that using high TDS water might not be suitable for some delicate fabrics. Most Indian homes now use washing machines, though washing machines save a lot of time and effort but also result in a lot of wastage of water. You can create an overhead tank that collects the RO waste water and use the wastewater from this tank directly in your washing machine (do keep in mind the fact about delicate fabrics). This tip works best for semi-automatic & twin tub washing machines.
6. Cleaning and Flushing Your Toilets
Another big source of clean water wastage in modern homes is the use of toilet flush. Every single flush sends approximately 5 to 7 litres of potable water down the drain.RO waste water can be used effectively to reduce this wastage of clean water by using it to flush your toilets. When you start, always monitor your toilet seats for any discoloration on porcelain surfaces after a few days. With a periodical cleanup using common toilet cleaners, the chances of discoloration and salt deposits can be avoided.
Looking for an RO purifier that produces very little or no wastewater? Check out KENT RO Water Purifiers. These purifiers use Save Water Technology which recovers up to 50% pure water and stores the rejected water in a separate tank.
Every year we read and listen to the news of farmers committing suicide because of droughts. And there are thousands and lakhs of families in our country who have to travel for miles every day to collect drinking water. If you are fortunate enough to be blessed with a sufficient water supply, think of it as a privilege.
Do your bit by saving every drop of water. These small measures can make a lot of difference because EVERY DROP COUNTS.
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It was useful learning of RO waste water.
This is a foolproof method that my family has been doing for a long time.
Can we input the RO wastage to the same purifier for re-purification?
I also want to ask same
No, you shouldn’t send back the RO reject water directly for re-purification. However, the latest ‘Zero Water Wastage’ technology from Kent sends back the RO reject water to your overhead tank. In this approach, a low volume of RO reject water is mixed with a large volume of freshwater. This approach ensures that the TDS level of the unpurified input water remains as close to the freshwater as possible. Kent Grand Plus has an internal water booster pump for this purpose.
I use the same technique for 60 liter water tank to re-use reject water. I put 60 liter fresh municipal water (190 TDS) in tank and directed waste water(200 TDS) pipe in it. Then get 20 liter filtered water (10 TDS) and use remaining 40 liter for gardening/toilet. Do you think it will effective?
That’s because the RO reject water generally of dissolved solids and boiling can’t remove dissolved solids
India will face a severe water shortage soon as most of the houses have RO. The citizens are not worried about wastewater and neither the government of the day. The rejected water of RO is let into the drain. In my personal experience in my own house except me none other will touch the wastewater though it has only 600TDS reading. I use it for bathing and clothes washing but not other family members so even after my usage much water is wasted. There should be campaigns to educate the people. If data is collected on this colossal wastage of rejected water every day it will be mind-boggling when some states have millions of rural households struggling to get reasonably good water.
can we drink the waste water after boiling?
No, definitely not. That’s because the RO reject water generally has a high concentration of dissolved solids and boiling can’t remove dissolved solids.
swarna, I like your point. I am also interested in finding out solution at a large scale rather than individual scale. anyones inputs will be highly appreciated.
If the TDS of tap water is around 500, what could be the TDS of the RO reject water?
There is no fixed rule for this, but the TDS of the RO reject water would be a little higher than the TDS of the input water.
Nobody is mentioned the best use of RO reject water , it is best to to use for the gardening , the groth of plants is very high as this reject water having 200% bacteria which helps to grow very faster , Even we can send back the reject water to the ground for recycle of again and again
Article is very good and eyeopening for RO users.
Just wanted to know, of TDS level is high can we use for gardening.
can we use reject water for any plant or trees.
Hi im planning to use the reject water for a backyard fish pond, is it okay? How about for a swimming pool, rejected water treated with a chlorine for the pool?
For the fish pond, you will have to check the pH value of the reject water. The pH value should be from 6.5 to 9.0. The reject water can be used for the pool but keep a check on the TDS value of the reject water. If it is too high then do not use it in the pool.
If you are currently using the same source of water for your pool and the RO purifier then in most cases you can use the RO reject water for your pool. But this may lead to higher salt deposits in the pool and increase your maintenance.
Can we use the RO waste water to Turbine?
What if we re – RO (filter) the rejected water again with the same machine. My fresh tap water TDS is 120, filtered water is 4, and reject water is 180(max). Pls suggest, can’t that amount of water getting wasted.
That depends on the water quality specifications of the turbine you are using.
What if I mistakenly drink wastewater RO for a week instead of purified water?
If the incoming water is severly contaminated then drinking RO wastewater can potentially lead to stomach infections, Typhoid fever, and several other waterborne diseases.