How much water saving is enough? How much water should a person aim to use a day, generally, but definitely in level 3B water restrictions? The challenge is on...

In the Supreme Court of Appeal Judgment, Case No: 489/08, it was declared that "42 litres water per resident per day would constitute sufficient water in terms of s 27(1) of the Constitution."

We think an aim of less than 50L potable water a day is a very achievable goal - can you do it?

How do you know how much water you are using?

One could measure it all out, cup per cup ... but that's time consuming. An easy way is to find your water meter and take two readings, a time (e.g. a month) apart  (made easier by the DropDrop app), take that water consumption for e.g. a month and divide by 30 days, then divide by the number of people the meter is serving. That gives you an average estimate of the water use per person.

How much water (potable and other) do you need?

Water needs depend on what you are doing and where you are. We need about 20L per person per day just for survival, depending on how healthy we are. When we need to maintain ourselves, cleaning ourselves and our clothes etc, then we need more. Growing food, and becoming economically active needs even more, but we can still be smart about that water use.

It should also be clear that only the water for survival needs to be potable - of drinking quality. Fit for purpose use means you can reuse water, getting more bang for buck. Designing in water sensitive ways means that you can use more of the water in the ecosystem more productively, while nurturing the ecosystem that supports you.

water consumption needs

Image illustrating estimated water use per capita per day adapted from the World Health Organisation (WHO).

Some water researchers on their current water use (in a freestanding house with a garden):

Kirsty Carden, Urban Water Management, Civil Engineering. "My family and I aim to use less than 100L a day. We are currently around 80L. We take short showers and reuse as much of our greywater as we can."

Bernelle Verster, Researcher, Future Water Institute "I think I use about 36L a day. I have a house designed for water sensitive living; I use a dry toilet and don't shower every day. Further I don't cook a lot, survive off sandwiches and beer and don't wash dishes often. I outsource my clothes washing to my boyfriend's house, so that's maybe cheating a little. I think the beer's water footprint is probably the biggest bad thing though."

Kevin Winter, Sustainability Researcher, "Just confirmed my water consumption in my household - about 60 litres per person per day over last 4 months. 50L and lower is a do-able target to achieve with 3B restrictions."