South Africa, and the Western Cape in particular, is no stranger to having to think creatively about ways in which to save water. As a result of initiatives to stave off the city’s worst-ever drought, between 2015 and 2018 Cape Town residents and businesses managed to reduce their water usage by half. But without the imminent threat of a ‘Day Zero’, how can we continue to sustainably reduce water consumption and make sure that the water we do use gets put to as many uses as possible?

The rise of greywater

One water-saving initiative gaining increasing interest is the use of greywater. Greywater can be broadly defined as non-potable water, i.e. water you can’t drink. The most common forms of greywater that can be collected in our households include wastewater saved from baths, showers, washing machines and bathroom sinks. This water can then be put to other uses that we’d otherwise use tap water for, including for flushing toilets and gardening. So, with the potential to limit potable water consumption, reduce water bills and (quite literally) feed our household plant addictions, we’ve compiled a guide on how to use greywater efficiently and safely.

Firstly, what not to do

Whilst greywater is technically any non-potable water source, the reality is that not all wastewater is created equal. Toilet water is, of course, a No for re-use at home, as is water from our kitchen sinks and dishwashers due to its high fat content which can kill plants and grass. Especially if you have installed an irrigation system (more on that later), greywater is safe to use, however it is recommended that after collection it’s re-used within 24 hours to avoid the possible collection of bacteria.

Optimising greywater for use on plants

With gardening taking up to 50% of South African domestic water use, using greywater on our gardens and plants makes both financial and environmental sense. More good news is that greywater includes small amounts of nitrogen and phosphorus that act as a potential nutrient source for plants, and its soapy quality acts as a natural pest repellent. It is a good idea however to take note of the detergents and soaps you are using at home, with biodegradable and PH neutral products being the most grey water-friendly (see our guide to the best products to use here). Lastly, monitor your plants’ reaction to the introduction of greywater and every so often give them a rinse with rain or tap water. Plants that particularly enjoy greywater include fruit trees, yuccas, conifers and hardy herbs such as rosemary and bay. Flowers can also be watered with greywater. 

Setting up your greywater system

A DIY home greywater system can be as simple as collecting your wastewater in a bucket for use in the garden or toilet and an old sock or cut off tight that can be put on the end of pipes to filter any larger pieces of debris from your water. This works perfectly well for many people, however, if you decide to make a more long term commitment to using greywater, there are many products available that can help you run a more efficient system. The cheapest choice is going to a DIY shop and buying pipes and a water filter yourself, however, various local companies have created kits for water conscious South Africans. You can find this Greyway Automated Grey Water Harvesting System for R3 499, or a more sophisticated solution with Fish Hoek based Garden Res-Q. Whatever system you go for, opting to use greywater can be a smart choice for the environment, your wallet as well as your thirsty plants. Get saving!  

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