The need to act on curbing greenhouse gas emissions to avoid a dangerous rise in global temperature is well known. While national governments are working their way to reach a global carbon accord in Paris later this year, much can be done at local level to turn the tide. Cities and their citizens can make a lasting contribution by changing their habits and practices. Largely unknown outside the water sector, is the opportunity that exists to change the energy and carbon footprints of the urban water cycle: the way we manage and discard our water and used waters.

The energy used to supply water to cities and clean used water is responsible for 3 – 8% of global greenhouse gas emissions. This is roughly similar to all global air traffic emissions. Increasing energy efficiency and producing energy from the urban water cycle can result in ‘urban water’ becoming a net energy producer and can even achieve carbon neutrality. This would not only help to curb a good chunk of greenhouse gas emissions, it would also reduce the energy bills of consumers, utilities and industries alike.

Ruhrverband, a German water utility, for example, has worked for more than a decade on reducing their energy and carbon footprint. They now manage to deliver water and to clean used water, in a close to energy and carbon neutral fashion. Efficiency gains have been integrated with producing green energy. The efficiency gains have come from painstakingly fixing leaks and installing energy efficient appliances such as pumps and aeration systems. The green energy production is derived from generating (hydro) power from the water supply stored in the reservoir, and producing biogas from used water and other organic solid waste.

Around the world, other utilities are now following this example. Recent studies carried out by the IWA show that utilities in Mexico, Peru and Thailand can reduce their carbon emissions by between 20 – 35% in a relatively easy way: fixing leakages and producing hydropower from water running in pipes.

While utilities can contribute significantly, an even more astounding contribution to reduce the energy and carbon footprint of water use can be made by citizens. About 60% of household level energy is used to heat water for cooking, showering and washing. Over the last decade we have already seen a significant increase in efficiency at household level of water use. For example, in Europe, the introduction of water efficient appliances such as washing machines and shower heads has made s ignigicant difference.

As a result total water consumption is falling year by year. New technologies are now appearing on the market to capture the heat that is put in water and re-using rather than leaking it away in drains and sewers. Highly efficient water boilers, heat exchange appliances in showers and ever more efficient washing machines.

Utilities and their leaders have a major role to play in the transition of the energy footprint of the urban water cycle. Well within their reach is the development and implementation of energy savings and production plans that reduce costs and make their operation far less affected by fluctuating energy prices. Through informing their household clients, they can be pro-active and help consumers change behavior and reduce energy and water consumption. In connecting to industry they can be pivotal in transforming the total urban water cycle and its energy footprint. Yet, they can’t do it alone.

To enable the required transformation we need the powerful combination of entrepreneurship and regulation to be aligned. Creating a market for more efficient appliances needs regulation to allow market entry of new technologies and incentives to end wasteful usage. Allowing and stimulating pilot schemes to demonstrate proof of concept and practice is critical as a stepping stone to wide-scale adoption. Reviewing water and energy tarifs while water and energy saving technology become widespread can be a further stimulus in the transition.

However, impact and progress will only happen by bringing along consumers and citizens. To alter the energy footprint of the urban water cycle, citizens and consumer organizations can play a key role. Bringing citizens’ groups together to develop collective action, for example at neighborhood level, can become emblematic to change paradigms and practices. Engaging citizens in the urban water cycle energy transition is a fantastic way to connect many more people to the needed action to curb greenhouse gas emissions. Let’s act together and act responsibly and swiftly as we have little time to loose.