With the imminent arrival of Day Zero, Capetonians have been dashing to the stores to stockpile water for when taps run dry.

Cape Town retail stores including Pick 'n Pay, Shoprite and Woolworths have reported increases in bottled water sales.

"Customers have been buying more bottled water in the region over the past few days. We are taking steps to increase stocks from suppliers," said Pick 'n Pay group executive of strategy and corporate affairs David North. 

South African National Bottled Water Association chairperson John Weaver confirmed reports that five-litre bottles of water were being sold out within hours of being delivered in Cape Town stores.

The increased demand for bottled water has led Pick 'n Pay and Woolworths to impose limitations on the purchase of water.

"[We] are asking customers to limit their purchases of water to 50 litres. We know that everyone will understand why we have taken this temporary step to make sure we are able to serve as many customers as we can," said North.

Woolworths, which has a "buy 2 save R15" promotion, also limited the purchase of water per customer. 

"We have imposed a limit of 20 units of five-litre bottles (100 litres) per customer per day. This is to ensure fair availability to all our customers," said head of Long Life for Woolworths, Chan Pillay.

 Shoprite has no plans to limit the purchase of water per person, according to their media statement.

"We hope we will never be forced into a position where we have to do this and are preparing as much as we can to ensure that we are not in this situation by securing supply.

"But it is difficult at this stage to determine the level of demand from Day Zero, or how long the water cuts will last," the retailer said.