Jun 12


Save the grey water from a Reverse Osmosis System and it’s filtration process

When it comes to usable water, places like Cape Town and the Eastern Cape are in dire times, with still high demand, but limited supply. Conserving is the word of the moment. To avoid “Day Zero”, the majority of Capetonians are using different methods to save every drop possible, such as taking shorter showers, not water gardens and turning off the faucet while brushing their teeth, to name but a few.

Although it’s crucial that we as South Africans take responsibility for our water usage, it’s vital that our water is also safe for consumption, especially as while the water levels are low. This is why installing a Reverse Osmosis Water System could be the best option for most households, as it assists with safe drinking water, as well as saving.

What is Reverse Osmosis?

Reverse Osmosis, also known as RO, is an operation where you deionise or demineralise water through the action of forcing water through a semi-permeable Reverse Osmosis Membrane, while under pressure.

What does this do?

As water enters, salts, as well as other contaminants will not be able to pass and will be discharged through the reject stream. This water is then fed back into the feed water supply, so it can be recycled through the Reverse Osmosis System to save water. The water that goes into the RO membrane is known as product water, which contains 95% to 99% of dissolved salts removed from it.

What is feed water?

Feed water, commonly known as the reject water, contains contaminants such as chlorine and high amounts of salt. In most cases, this wouldn’t be safe to quench one’s thirst. However, this “grey water” can be used for other things around the home. Instead of connecting the pipe to a drainage source rather attach it to collection tanks or a bucket. The collected water can be used as elaborated on below.

How to reuse feed water from a Reverse Osmosis System

Toilet flushing

The average household toilet uses around 9 litres of water. Instead of wasting fresh, clean water, use the “greywater” from your reverse osmosis system, to flush your toilet, by doing this, you’re limiting and managing your water usage as a toilet bowl does not require a huge amount of water to clean it.

Car washing

Nobody enjoys driving a filthy car, but with the harsh drought and water restrictions, cleanliness for our wheels can be hard to achieve.  Water from a Reverse Osmosis System is perfectly safe for us to scrub our “babies” down. Avoid using the garden hose, as this could use several litres of precious water.

Maintain your garden

Is there anything more depressing than gardening your fingers to the bone, only for your beautiful plants to deteriorate due to a lack of water? Don’t let your hard work go to waste, use the waste water from your Reverse Osmosis System to water your thirsty plants or crops.


Majority of households use washing machines instead of washing their clothes by hand. Washing by hand can be strenuous, so most revert to washing clothes in a washing machine which saves time but uses a lot of water. Instead of using tap water, use your Reverse Osmosis System wastewater.

71% of the earth’s surface is covered in water of which 96.5% of the planet’s water can be found in our oceans. This means we only have 2.5% for use as fresh water. It’s up to us as a society, to help save and use wastewater as often as we can.