Origins: the Carlshütte

ACO’s history is closely connected with the Carlshütte iron foundry, an industrial enterprise founded in 1827 in Büdelsdorf. The Ahlmann family’s involvement with the foundry began in the 19th century; Johannes Ahlmann became its commercial director in 1883.[1]

A particularly important figure in ACO’s history was Käte Ahlmann, who took over management of the Carlshütte in 1931. During the Second World War and post-war period, the company faced restrictions on the use of iron. This contributed to the development of a concrete division within the foundry.[1]

Foundation in 1946

On 10 December 1946, Käte Ahlmann’s son Josef-Severin Ahlmann established an independent company based on the Carlshütte’s concrete division. It was initially known as Severin Ahlmann Betonindustrie (SAB).[1]

The new company initially produced products needed for the reconstruction of post-war Germany, including:

• Concrete pipes
• Kerbstones
• Manhole components
• Concrete slabs
• Window frames
• Wash troughs
• Sanitary products
• Prefabricated garages

ACO’s early business was therefore considerably broader than its modern reputation as a drainage specialist.[1]

During the 1960s, the various businesses associated with the Ahlmann family used different names, which created difficulties in establishing a consistent market identity. The abbreviation ACO, derived from Ahlmann & Co., was progressively introduced as a common brand.[2]

The ACO name eventually became the group’s principal international identity. This transition was significant as the company moved from being a collection of regional manufacturing businesses toward a recognisable technology brand.

One of the most important turning points came in the late 1960s and early 1970s, when ACO began concentrating increasingly on drainage technology.

In 1969, ACO entered the drainage business with ACO DRAIN. The company subsequently developed drainage channels using polymer concrete, a material that became an important part of ACO’s technological portfolio.[1]

A major early reference project was the 1972 Olympic Games in Munich, where ACO drainage technology was used for the Olympic Stadium and associated facilities. This helped establish ACO DRAIN as an important product and contributed to the company’s subsequent international expansion.[1]

ACO began internationalising its operations during the 1970s. Production and commercial operations expanded first into European markets and subsequently into North America, Australia, Asia, Eastern Europe and other regions.[1]

The company states that its international network now encompasses more than 50 countries and all continents. Rather than operating solely as an exporter from Germany, ACO developed local subsidiaries and production facilities to serve regional construction and infrastructure markets.[1]

This internationalisation became a central part of ACO’s growth strategy.

ACO remains a family enterprise, with ownership and strategic leadership continuing through successive generations of the Ahlmann family.

Hans-Julius Ahlmann joined the company in 1981 and played a major role in its internationalisation and development into a global drainage-technology business.[1]

The next generation followed with Iver Ahlmann, who joined the company in 2010 and became managing director in 2012. ACO’s current corporate information identifies Hans-Julius Ahlmann and Iver Ahlmann as representing the present and future of the family enterprise.[1]

ACO’s modern portfolio extends well beyond simple drainage channels. The company describes its approach as covering different stages of the water cycle, particularly drainage, cleaning, controlled discharge and reuse of water.[1]

Major product and technology categories include:

Drainage systems

ACO produces drainage channels, surface drains, gullies and related systems for applications such as:

• Roads
• Pedestrian areas
• Commercial developments
• Residential construction
• Industrial facilities
• Airports
• Sports facilities
• Public spaces
• Infrastructure projects

The ACO DRAIN product family is one of the company’s best-known technologies.

Water treatment

ACO also develops systems designed to remove pollutants from water before it is discharged or reused. These include technologies for handling:

• Hydrocarbons
• Sediment
• Grease
• Wastewater contaminants

Oil and grease separators

ACO produces oil separators and grease separators for applications where contaminated water must be treated before entering drainage or wastewater systems.[1]

Backflow protection

Another area is protection against wastewater or stormwater flowing backward into buildings. ACO offers backflow stop systems and associated building-drainage technologies.[1]

Pumps and wastewater technology

The company also manufactures pumping and wastewater-management systems, extending its role from simply collecting water to helping manage its movement through infrastructure.

Building drainage

ACO products are used in building environments through systems such as:

• Floor drains
• Shower drainage
• Basement drainage
• Cellar windows
• Light wells
• Pressure-water-tight building components

ACO’s portfolio therefore covers both external surface-water management and building drainage.[1]

Material science has been an important part of ACO’s development. The company currently highlights expertise in several major materials, including:

• Polymer concrete
• Plastic
• Cast iron
• Stainless steel
• Reinforced concrete

This allows ACO to select different materials according to the structural, chemical, environmental and load requirements of a particular application.[1]

The development of polymer concrete in particular was significant to ACO’s transformation into a drainage-technology company. The material enabled the company to produce drainage channels with characteristics suited to demanding infrastructure applications.[1]

The central idea behind ACO’s modern business is water management rather than simply drainage. Traditional drainage systems are primarily concerned with getting water away from a location. ACO’s contemporary approach is broader: water may need to be collected, transported, cleaned, controlled, discharged or reused depending on the situation.[1]

This is particularly relevant as cities face:

• More intense rainfall
• Flooding
• Urbanisation
• Increasing impermeable surfaces
• Water pollution
• Pressure on wastewater infrastructure
• The need for greater water reuse

ACO positions its technology as part of the infrastructure required to respond to these challenges.

ACO technology can be found in a wide variety of environments, including:

• Architecture and buildings: Residential buildings, commercial properties, public buildings and industrial facilities.
• Transport infrastructure: Roads, bridges, airports and other transportation facilities.
• Urban infrastructure: Streets, pedestrian areas, plazas and public spaces.
• Industrial facilities: Factories and areas where contaminated water must be collected and treated.
• Sports facilities: Stadiums and sporting venues.
• Food and commercial facilities: Areas requiring specialised drainage and grease-management systems.
• Infrastructure projects: Large-scale developments requiring integrated surface-water and wastewater management.

ACO notes that its products have been used at prominent international locations, including the Statue of Liberty, Elbphilharmonie and Olympic Stadium in Munich.[1]

ACO’s current corporate positioning centres on the idea:

“ACO. we care for water”

The company presents water as both an engineering challenge and an environmental responsibility. Its stated objective is to develop infrastructure that manages water responsibly while contributing to resilient and sustainable communities.[1]

This represents a significant evolution from the company’s original post-war identity as a manufacturer of concrete construction products.

As of 2026, ACO describes itself as a global, family-owned WaterTech company with decades of experience in rainwater and wastewater management. It operates through a network of companies and production facilities in more than 50 countries.[1]

The group has approximately 5,500 employees and generated €1.16 billion in sales in 2025. Its headquarters remain in the Büdelsdorf/Rendsburg area of northern Germany, close to the location where the company was founded in 1946.[1]

The company continues to invest in research and development, material technology and integrated water-management solutions, while retaining its family-business structure.

1. About the ACO Group
2. Main Page – Aco Wiki