The District building, in Woodstock, has become the first of Growthpoint Properties’ commercial properties in Cape Town to shift off the municipal water grid and become water net-positive.
The property giant on Thursday said the 1 750 people using the multi-tenant office and retail building consume an aggregate 45 000 ℓ/d of water.
The building, which has seven floors and five basement levels with 18 721 m2 of lettable area accommodating 25 businesses, is now using a naturally occurring underground mountain spring that flows to the building’s basement and is provided at the same rate as the municipal water.
Some 140 000 ℓ/d of water flows naturally through the sump and the building's new filtration plant, located in its own sterile glass-fronted room in the basement, has been designed to clean the entire flow.
To prevent flooding, the spring water has traditionally been pumped from the basement sump into the city’s stormwater system.
The design has also prevented Growthpoint from using the sump water as grey water for flushing the building's toilets.
“It is incredibly frustrating to have a sustainable alternative water source that has to be flushed down the drain because it is not safe to drink. So, we challenged ourselves to find a way to use the sump to provide drinking water that is completely safe for human consumption for the entire building,” said Growthpoint regional asset manager for the Western Cape Timothy Irvine.
The legislation that the City of Cape Town drafted to enable Growthpoint to produce water on a large scale came into effect in November 2017, when Growthpoint was given the go-ahead to become a water services intermediary.
However, this means the building owners can supply water only to those with which it has a contractual obligation – its tenants.
The District is the first of a number of buildings that Growthpoint intends to take off the municipal water grid, with plans to convert the water source of its 200 on Main property next.
“By taking The District and other commercial buildings off the water grid, and substituting municipal water with a safe and sustainable alternative source of drinking water, we are taking pressure off the city’s potable water reserves, adding to the resilience of the city’s water system, and contributing positively to the environment,” he said.
“Net-zero water initiatives are an important part of Growthpoint’s journey as it strives to make all its new developments net-zero by 2030,” he added.
All the buildings identified are in Cape Town, as this is the only city with the legislation in place to enable it; however, Growthpoint would consider working with authorities in other cities to pursue net-zero water ambitions for suitable buildings.