How To Reuse Water From Water Purifier At Home

Glass of pure water on restaurant table outdoors. Bali island.

Most homes have installed RO water purifiers as these devices assure safe and clean drinking water that also tastes well and protects the users from water-borne diseases. The one downside that the users often find with the RO water purifying systems is that they also mean excessive wastage of water.

RO systems and wastewater

Glass of pure water on restaurant table outdoors. Bali island.
Glass of pure water on restaurant table outdoors. Bali island. Indonesia.

In an average, an RO system wastes up to 3 liters of water for every 1 liter of water purified. This will mean that from an RO system, about 75% of water comes out as waste. If you wonder why this much water is wasted, the reason is simple. The Reverse Osmosis technology employed by the RO systems need to filter out the dissolved impurities and the process will create a significant amount of reject water. Due to the high levels of the dissolved solids or impurities found in the reject water, it is not safe for bathing or drinking. However, this water can be reused in some other ways discussed hereunder.

What to ensure before reusing the RO wastewater?

Before thinking of reusing the RO wastewater for other purposes, it is good to determine the TDS levels of the reject water. If the TDS level is too high in the wastewater, it might not suit most of the reusing applications given here. If this is the case, still there is a way out. Mix the RO reject water with regular tap water to dilute and then all these following reuses can be thought of in a safe way.


A carwash can consume anywhere between 15 liters of water to 75 liters depending on the method you choose – using a bucket or spraying the water through a hose. When you use an RO purifier at home, you can think of storing the wastewater in a tank or bucket and use it for washing your car. The safe TDS level for washing a car is 1200 – 1500 PPM. If the TDS is more than this, dilute the wastewater with tap water to bring down the TDS level.

Watering plants

If you have planted some plants in pots or in the garden or on the terrace, you can use the RO wastewater to water them. Especially this will prove useful in urban locations where the TDS levels of the municipal water are very low. Administer the RO waste water on some select plants for about two weeks to check the effect of the wastewater on it. Using water up to 2100 PPM for gardening is permissible.

Washing utensils

Washing utensils is one of the most popular applications of RO wastewater. To do this, you can store the RO wastewater is a bucket near the kitchen sink and use it while cleaning the vessels.

Mopping the floor

You can use the RO wastewater for mopping the floor. In case the TDS level of this reject water is higher than 2000 PPM, you can dilute it with the regular tap water. Also, think of using the RO wastewater for mopping the floor on alternative days in order to see that you avoid the salty deposits or stains on the floor.

Leave a Reply

Your email address will not be published. Required fields are marked *