Your office toilet uses 90 percent of your company’s water

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The 30th driest country in the world, 98% of South Africa’s water resources are already allocated, and lower than average rainfall together with increasing demand has placed the country in a serious water crisis. Office buildings consume almost half the municipal water supply, although they make up just 10% of customers, with office bathrooms responsible for up to 90% of a commercial building’s consumption and also the greatest source of leaks and inefficient water use.

A study we did at the University of Stellenbosch Business School (USB) found that in one office building alone in Gauteng, yearly water consumption – and associated costs – was cut by 87% simply by addressing a major leak, introducing efficient toilet flushing mechanisms, and installing smart metering to monitor and manage consumption.

We investigated the potential of the commercial sector, given its large draw on municipal water resources, to reduce its demand by eliminating inefficiencies, which in turn could lead to significant cost savings for landlords and tenants. The cumulative efforts of individuals can make a significant impact, as seen in the results of water-savings campaigns during the recent drought in the Western Cape, but getting large commercial consumers to reduce consumption significantly by eliminating waste and increasing efficiencies, can have a ‘quicker’ impact on our country’s water crisis.

And it makes business sense. The impact of more efficient monitoring of water usage and reducing consumption by toilets goes beyond cost savings. Because toilets contribute the most to wastewater infrastructure, reducing the wastewater into the system would enable treatment plants to operate more efficiently and discharge less effluent into the environment.

In short, lower consumption generates less waste. Government and municipalities save on reticulation and wastewater treatment costs (savings that can be used to maintain current infrastructure). The end user saves money. The environment recovers. Population growth and urbanisation is driving up demand for water at the same time as deteriorating infrastructure makes it increasingly difficult for local authorities to meet demand and to process wastewater effectively.

Water scarcity in South Africa is not a temporary problem. While drought might not be making headlines, we need to understand that one good rainy season only lightens the load on the system for a short time but cannot permanently supply an ever-increasing demand. Using smart water metering and data logging, we monitored water consumption of 30 office buildings in Gauteng and the Western Cape, to understand usage patterns and identify inefficiencies, leaks and opportunities for savings.

Understanding water consumption patterns is the key to identifying and addressing the worst inefficiencies – where the most water is wasted – so that increased demand can be met. In the case study of the Gauteng office building, we found 55% of annual consumption of 21,814kl was lost to a leak. Once the leak was fixed and smart metering, efficient flushing mechanisms and pressure-reducing valves were installed, the building’s annual water consumption dropped to less than 3,000kl – resulting in a water bill of under R100,000, and a cost-saving of more than R600,000 per year.

The main contributors to water consumption in the office buildings are toilets, canteens/kitchens, irrigation, cleaning services and air-conditioning, with toilets by far the biggest consumers. If not managed properly, toilets can be a thorn in the side for any facility manager or financial manager. By default, a toilet is a mechanism intended to consume water as part of its design, and if not properly maintained, can also waste a lot of water.

Some recommendations for more efficient water usage include installing automatic meter reading (AMR) devices to monitor consumption volumes and patterns, enabling quick detection of abnormal usage. From the data obtained, look for the “obvious contributors” to high demand, i.e. irrigation systems, cooling towers, hot water cylinders, leaks, and toilets, and reduce demand by eliminating inefficiencies. 

This could include measures such as (i) ensuring automated irrigation systems are not over-irrigating, and using smart technology to monitor weather patterns and change the schedule accordingly, (ii) reducing the running time of cooling and ventilation systems to only times when buildings are occupied, (iii) installing high efficiency toilets and (iv) actively raise awareness in workplaces and education facilities on water conservation practices.

Gerrie Brink is an MBA graduate of the University of Stellenbosch Business School (USB) and conducted the research as part of his degree. He launched #SurplusWater2025, to assist individuals and companies in investing wisely in water security.