This week we sat down for an exclusive interview with Carolyn Hogg, Managing Director of Cascade Water Products, and panelist at today's New York Times Climate Hub event at COP26 in Glasgow.

Carolyn discussed the importance of water efficiency in UK businesses, the benefits of commercial greywater recycling, and why the return on investment is more than just money.

Tell us about your company, Cascade Water Products, and your greywater recycling product, Aqua Gratis.

Cascade Water Products is a purpose driven enterprise. By developing and commercialising low cost, easy to fit, use and maintain short retention micro domestic and commercial greywater reuse technology, our award-winning team will make the world a better place. Sustainable water is one of the biggest challenges facing the world.

What makes Aqua Gratis unique?

Designed to be low cost, Aqua Gratis is an easy to fit use and maintain micro greywater reuse system. It is energy efficient using 5 KWH a year and constructed mindfully for the circular economy, only capturing the bath/shower water to only flush toilets. As part of The Internet of Things, the control panel functions as a Remote Monitoring System and Smart Meter for Water. This can increase water savings a further 15%. A Zero Waste Scotland study concluded it is carbon negative, except in single occupancy homes.

A simple solution, Aqua Gratis’ unique selling points have been developed through the innovative engineering used to create the system. These make the system significantly more attractive to developers.

One Aqua Gratis system services a small business premises and multiple WC’s.

  • It is in the category of short retention systems.
  • Carefully constructed with off the shelf parts to help keeps costs down.
  • Bespoke components and the overall system assembly to keep cost down.
  • It is energy efficient, low maintenance with minimal service requirements.
  • The control panel manages water in the system optimising freshness and availability.
  • Water treatment using innovative biodegradable biocide.
  • Energy efficient – 5KWH per year
  • Built to surpass the British Standard 8525 for greywater reuse.
  • Gravity fed toilet.
  • Innovative gravity fed self-cleaning filters, back flushable filters preventing larger particulates and hair entering the system. Cleaning cycle which keeps the water fresh without wasting precious water.
  • Can be fitted inside or outside the business premises.

For which industries is Aqua Gratis appropriate for install, and what are the advantages to greywater recycling in a commercial environment?

Aqua Gratis reduces the need for domestic and commercial water supply by up to 30%. There is a synergy between water used for baths and showers and toilet flushing. If your business has shower facilities for employees or customers, for example a leisure, sports facility, hotel or accommodation provider, schools, universities and colleges, then you can significantly cut water and wastewater bills. The return on investment is more than money. Aqua Gratis addresses water supply, demand management, wastewater and sewage and achieving net zero. Water is the missing element in making carbon and greenhouse gas reductions.

If your business has shower facilities for employees or customers, for example a leisure, sports facility, hotel or accommodation provider, schools, universities and colleges, then you can significantly cut water and wastewater bills.

What keeps you motivated to bring Aqua Gratis to market, despite obstacles and challenges you’ve faced?

When I started out on this journey, I just thought it was a good idea. At that time my teenage boys had long hot showers and I made the connection with wasting water and energy. Then I discovered 50 cities in America were expected to run out of water in 2050. Research showed a global issue with water supply. In 2015 with the Paris Agreement, I thought “Great, we will get more help.” No. Water is right down the list of priorities.

In 2015 Sao Paul nearly ran out of water. In 2018 it was Cape Town’s turn. Search ‘cities running out of water’ and you will get a list showing the global issue affecting many millions of people.

I kept on and Peter Holdsworth, Chief Technology Officer for Cascade Water Products, kept developing the system. Friends, family and supporters kept us going. I must give much credit to my late mother; she was a brilliant. We won some awards including funding from Scottish Edge and Innovate UK. The timing of their awards was crucial in building prototypes. We now have our production model and will have it independently accredited in the new year.

We have attracted interest from water companies, developers like Barratts, Cala Homes, and the Duchy of Cornwall. This summer we were contacted by two construction companies based in South America. One is looking for 500,000 systems over 10 years! We know hotel chains are interested too. In the greater London area new developments are needing to adopt water saving measures to get planning permission.

Earlier this year our work started to be recognised here in the UK. The Scottish Council for Development and Industry (SCDI) invited us to participate in research for a Climate Tech Report. From that we were invited to be on a panel and exhibit at their Scotland's Climate Ambition Zone - Scotland's COP26 Climate Tech Showcase (SCDI and ScotlandIS). Cascade is one of 16 companies selected to be on panel discussions and networking events.

You’re speaking at key events at COP26 in Glasgow this week, including The New York Times Climate Hub. What are the key issues you plan to raise, and what do you think needs done on a national or global scale to address them?

My aim is:

  1. to raise the global profile of domestic and commercial greywater reuse. Greywater reuse is the future. So, individuals, young and old, local and national governments, businesses, developers and construction companies need to be aware and educated on the benefits of greywater reuse and reducing water consumption. Water is an energy consuming sector. The public need to be made aware of this. A media campaign is required.
  2. To find investment. Water and Climate Tech is underfunded. Women led businesses are underfunded. Risk aversion needs to be overcome.
  3. To find customers and partners to grow our sales funnel. It has taken a long time to get to a production model. The world needs Aqua Gratis now and not in 16 years. Rapid scaling is essential.

Why is it important that UK businesses do more to be water efficient, when we live in a country with reliable, high rainfall?

  1. Climate change – to much rain, too little rain. Rain falling in the wrong place.
  2. Supply and demand management – since the 60s, and the modern bathroom experience, water use has rapidly increased. Increasing populations and migration; London’s population will increase by 2.1 million by 2045 and the water supply is not going to be adequate.
  3. Sewage contamination of rivers and water courses. Water companies are under pressure to stop releasing untreated sewage into rivers. Greywater use takes pressure off the sewage works by reducing commercial and domestic sewage.
  4. Net zero – the water industry is energy intensive. Water supply and especially treating sewage takes a lot of energy. Greywater reuse is the missing element of net zero homes. Hotels and accommodation providers should investigate greywater reuse.

What advice would you give to a UK business owner that is keen to become more water efficient to reduce their commercial carbon footprint?

Businesses are now expected to demonstrate their green credentials when applying for tenders. There are many tools online to help. However, water use is often not included. Thus, greywater as a solution is not included. So, be ahead of the pack and investigate greywater reuse. Find a system which suits your requirements. There are not many. Contact us for more information.

What’s next for Cascade Water Products?

We want to have Aqua Gratis independently accredited. Then we can go to market. We desire to have some pilot projects which can help provide data to help really understand the benefits of the system. Metrics are needing to be developed.

We are in discussions with oversees developers and New York City's Green Infrastructure Department, so we need to plan how to scale rapidly to meet the needs and demand around the world.

We need to grow our team and create partnerships to be able to deliver on the amazing opportunities we have been developing home and abroad. Then we can develop new products!

Carolyn Hogg is one of six panelists at The New York Times Climate Hub Event, All the Difference: Improving Our Systems From Within at COP26 in Glasgow on Thursday 11 November 2021.

About the event:

While many climate innovators dream about the new, others consider the old, and how it can be improved to better prepare us for life on a warming planet. Decarbonization at the speed needed to remain under the 1.5-degree threshold requires adaptation within existing systems, alongside the development of more exciting moonshot climate innovations and business models. What does internal systems change look like, and how can we learn from successful intrapreneurs? What shifts can we expect over the next few decades, and where are the appetite, resources and political will for improving existing systems? What adjustments must be made to render our systems more efficient and sustainable, and what lessons can we apply to our future solutions?

This session has been curated in collaboration with The University of Edinburgh as part of the Climate Innovators Initiative, which involved a vetting process and selection of diverse climate innovators.

All the Difference: Improving Our Systems From Within | The New York Times Climate Hub ( will be available to watch next week.

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