Clean water technology company RSE has today opened its first American-based office in Milwaukee, Wisconsin, taking the initial steps to catalyse its acquisition-focused North American growth strategy.

The new office, and its initial team of three, will be situated within the Global Water Center (GWC) technology cluster, marking a significant milestone in exporting RSE’s innovative water solutions to overseas markets.

RSE will join more than 30 other water-focused organisations in a 98,000 square foot campus dedicated to freshwater innovations.– from established engineering firms to start-ups – as well as university researchers and the headquarters for global nonprofit The Water Council.

This immediately gives RSE access to a concentrated network of potential partners, technology developers, and industry leaders.

RSE’s American team will primarily focus on supplying the company’s biological and nature-based treatment technologies. This includes its modular Moving Bed Biofilm Reactors (m-MBBR®) which are prefabricated units for wastewater treatment. Flexible for new sites or retrofitted treatment plants, m-MBBR® is particularly suited to meet rural demand at lower installation and operational costs.

RSE’s strategic partnership with, and investment in, Forres-based Biomatrix Water Solutions (Biomatrix) will also be instrumental as it deploys the company’s floating ecosystem solutions throughout the US market.

Made from both recycled and natural components and described by the company as a “living laboratory”, these habitat installations integrate natural processes to improve water quality and biodiversity in polluted freshwater bodies. They have also acted as an important resource for scientists to study the effects of plants on water conditions and animal life.

A standout example of the technology’s impacts in the wider Great Lakes region has been on the “Wild Mile” in Chicago – a stretch of the Chicago River previously listed among America’s most endangered due to high levels of water pollution. The introduction of Biomatrix’s floating wetlands in 2017 has gradually improved water conditions, transforming the once-industrialised area into the world’s first floating “eco park” and bringing tens of thousands of annual visitors to its sprawling network of boardwalks and native-plant gardens.

Stephen Slessor, CEO of RSE, commented:

“Whether working alone or in partnership, our tested technologies already address key challenges in the global water sector. This can be anything from rural communities in need of efficient and cost-effective treatment options, to restoring vibrancy to natural sanctuaries in the heart of large urban centres like Chicago.

“We are proud to mark this exciting new era for RSE and to welcome our American team to this new office. Now, we look forward to further growth through acquisition in this important market.”

RSE’s American expansion follows a period of significant growth in the UK. From its origins as a start-up in Muir of Ord in 1982, it now employs more than 2,000 people across 17 offices nationwide and, more recently, it has increased revenue from £61 million in 2019 to £360 million in 2025.

RSE currently delivers projects for the UK’s major water companies, as well as leading firms such as Diageo, Siemens, SSE, ScotRail, and EDF. The company’s commitment to the circular economy, carbon reduction, and cutting-edge engineering methods – including modular off-site fabrication and digital innovation – has enabled it to achieve company-wide Carbon Neutral status.