SA's loos not flushed with success

Using seawater and recycled water to flush toilets could save millions of litres of potable water daily

- Sheree Bega

Every day, South Africa’s coastal cities discharge roughly 300 million litres of wastewater into the sea. For Teboho Mofokeng, a water engineering lecturer and PhD candidate at the University of Cape Town researching water management and reuse, this is a lost opportunity.

She said that amount of water is enough to provide about 1.5 million to two million people with drinking water every day “and that is just from us flushing our toilets into the sea. Surely we can rethink what we are doing.”

Mofokeng is the co-author of a new study by researchers at the university who explored using seawater to flush toilets in Cape Town.

The research, commissioned by the Water Research Commission, found that Capetonians were willing to pay up to 10% more on their water bills to use seawater to flush their toilets — as long as it doesn’t smell or stain the bowls.

Mofokeng said water could also be treated to remove harmful bacteria and reused to flush toilets. But this would require a closed water system.

In Cape Town alone, 20% to 30% of the city’s drinkable water provided to households is used to flush toilets. As the demand for housing grows, so does the need for water and sanitation.

When new housing developments are connected to the water supply network, alternatives such as seawater and recycled water for toilets should be considered, rather than using potable water.

For their study, the researchers asked 239 people whether they would be willing to flush with seawater or recycled water — or continue to flush with drinking water but pay more to do so.

They were also asked how they felt about toilet wastewater being discharged into the sea.