EVERY drop counts!
Now more than ever, it’s vital to know the facts about grey water and rainwater; we help you make sense of how best to use both.
Grey water What is grey water?
Grey water is defined as used water from baths, showers, hand basins and washing machines. It does not include water from the toilet or kitchen.
Do I have to use biodegradable cleaning products if I use grey water to water my garden?
Many people say they’ve noticed an improvement in their grass and plants since using grey water in their garden. This is because of the grey water’s alkaline nature, which most plants love – with the exception of acid-loving plants such as azaleas, begonias, gardenias, hibiscus, camellias and ferns.
But in the long term, phosphate and salt buildup from constant grey water use can be toxic and your garden will suffer as a result.
Aim to use biodegradable dishwashing detergents and washing powders that are phosphate- and salt-free, and avoid liquid fabric softeners as they contain chemicals. If you can’t always use these products, flush your garden with stored rainwater once a week. Only use municipal water if there are no water restrictions.
For how long can I store grey water?
Because grey water contains bacteria that don’t need oxygen to grow (anaerobic bacteria) it poses a health risk, and will smell if stored for too long. For this reason, untreated grey water should always be used immediately. You can store it for up to 24 hours if you treat it with products that improve the water quality, such as Bio-Systems SA’s biological additives.
I’ve been using a bucket to carry grey water outside and then transferring it to a watering can to water my garden. Can you suggest a less time-consuming method?
Although your system of reusing water works, there are other methods that will reduce the time you spend going to and fro and lessen your contact with grey water and its potential health risks.
You could have the pipes from your bathroom and washing machine (which already has a built-in pump) connected to a grey water system in your garden or directly into a hosepipe.
This method works either by means of gravity (from an upstairs bathroom, for example) or a water pump. A siphon pump and tubing can be set up to pump bathwater out of a window and into a tank before it’s used in the garden.
Tip Don’t have biodegradable laundry liquid on hand? Then use only the water from your rinse cycle in the garden.
Did you know? When it comes to grey water systems, there’s no ‘one size fits all’. All homes are different and the differences – such as the layout, size and contents of the garden and the gradient of the property – will affect the installation price.
Rainwater What is rainwater harvesting?
This refers to the collection of water from surfaces on which rain falls and subsequently storing it for later use; usually, water is collected from roofs by means of downpipes and stored in rainwater tanks.
How long can I keep rainwater?
Untreated rainwater can last for up to six months in a rainwater tank. It’s best to invest in one that blocks out sunlight and UV rays as this is what causes algae to form.
Can I drink rainwater?
Because of increased acid levels in rainwater as a result of air pollution, as well as possible contamination from bird droppings on roofs, drinking untreated rainwater isn’t recommended. Some rainwater-harvesting systems filter and sterilise the water, or you can boil it continuously for at least a minute – both methods make it safe to drink.
I have steel water tanks; can I move them underground?
You could, but concrete water tanks work best underground in terms of maintenance and longevity; they’re load-bearing so they’re ideal underneath driveways and entertainment areas, for example.
W hat size rainwater tank should I buy?
Bigger tanks are ideal if you’re using the water in your garden and home. If you’re just using it to collect water for your garden, a small tank is ideal. Here’s how to calculate what size tank is sufficient for your rainwater harvesting needs: Roof p/m²: 50 – 100 tank size: 750L – 2 200L Roof p/m²: 200 – 400 tank size: 2 500L – 10 000L
I’ve seen signs up in our neighbourhood that indicate the use of grey water. Where do I get one and is it a must?
If you’re using grey water or rainwater to irrigate, you are obliged to put up a sign indicating the use of non-drinking water. You can find it on your city’s website and it should be printed A4 landscape. This is not the same sign as those used to indicate the use of wellpoints and boreholes.
I’ve recently bought large tanks to collect and store rainwater. How do I get it to my garden with the least amount of effort?
For a simple irrigation system, you’ll need to use a hose connected to the tank and distribute drip lines with drip nozzles in your garden, on the surface or just under the soil, allowing water to slowly drip into the ground.
More and more households are investing in rainwater harvesting tanks – they’re perfect for storing water when there are water restrictions and for saving costs on municipal water.
Go online to find out all you need to know about borehole water. Rainwater tank filter R882.61, sustainable.co.za JoJo Slimline water tank (750L) R2 908, jojotanks.co.za and builders.co.za