In modern water and wastewater treatment systems, the performance of a filtration unit often depends on one critical yet overlooked component — the underdrain filter system. Whether you are a municipal water authority, EPC contractor, environmental engineer, or industrial plant operator, selecting the right underdrain manufacturer directly impacts filtration efficiency, backwash performance, media longevity, and long-term operating costs.
As global water standards become more stringent and treatment facilities pursue higher efficiency and sustainability, demand for reliable and innovative underdrain filter solutions continues to rise. In this article, we highlight the Top 10 Underdrain Filter Manufacturers in the World 2026, showcasing industry leaders known for engineering strength, proven performance, and advanced air-water distribution technologies. This guide will help decision-makers identify trusted partners for municipal, industrial, and infrastructure filtration projects worldwide.
| Company Name | Headquarters |
| 1. Xylem | Washington, DC, USA |
| 2. De Nora Water Technologies | Milan, Italy |
| 3. Johnson Screens | New Brighton, Minnesota, USA |
| 4. AWI Filter | Calgary, Alberta, Canada |
| 5. Orthos Liquid Systems | Bluffton, South Carolina, USA |
| 6. WesTech Engineering | Salt Lake City, Utah, USA |
| 7. Roberts Filter Group | Coatesville, Pennsylvania, USA |
| 8. Veolia Water Technologies | Paris, France |
| 9. SUEZ | Paris, France |
| 10. Weilan Water Treatment Technology Co., Ltd. | Henan, China |
Company Profile:
Xylem is a global leader in water technology, providing innovative solutions for water and wastewater treatment across municipal, industrial, commercial, and agricultural sectors. Established in 2011 as a spin-off from ITT Corporation, Xylem operates in over 150 countries, delivering high-quality pumping systems, analytical instruments, and filtration technologies. The company is committed to solving critical water challenges efficiently, helping communities and industries manage, transport, and treat water sustainably.
Xylem’s Leopold brand is renowned for its advanced underdrain systems, designed to optimize filter performance in water treatment plants. Leopold underdrains, including Type S, Type SL, Type XA, and Type 360, ensure uniform water and air distribution, effective media retention, and reduced backwash consumption. These systems improve filter run times, simplify maintenance, and enhance operational reliability, making them ideal for municipal drinking water, wastewater reuse, and industrial filtration applications.
Establishment: 2011
Headquarters: Washington, DC, USA
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Company Profile:
De Nora Water Technologies is a global provider of advanced water and wastewater treatment solutions, specializing in electrochemical and filtration technologies that support sustainable water management. With a strong commitment to innovation, De Nora serves municipal, industrial, and commercial customers worldwide. The company focuses on delivering high‑performance systems that improve water quality, enhance filtration efficiency, and reduce operational costs across diverse applications.
In the underdrain filter market, De Nora is recognized for its reliable underdrain systems that deliver uniform distribution of air and water within filter beds. These underdrains are engineered for robust performance, consistent backwash effectiveness, and long service life. De Nora’s products support improved filter run times and minimized maintenance requirements, making them a trusted choice for surface water treatment plants, wastewater facilities, and industrial filtration systems.
Establishment: 1923
Headquarters: Milan, Italy
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Company Profile:
Johnson Screens, a brand of the Aqseptence Group, is a global provider of engineered screen and filtration solutions with over a century of experience in liquid/solid separation technology. Founded in 1904 and now serving clients in more than 100 countries, the company is known for its trademarked Vee-Wire® screen profiles that deliver high strength, precision, and durability across diverse markets including water treatment, industrial processing, and environmental applications. Johnson Screens combines robust engineering with global field support to deliver reliable filtration systems and components.
In the underdrain filter sector, Johnson Screens is recognized for its Triton® Underdrain Systems, which utilize Vee-Wire® technology to optimize water and air collection, media retention, and backwash distribution. These underdrains deliver high open area, reduced headloss, and improved bed fluidization, resulting in longer filter runs, better media cleaning, and reduced backwash energy consumption. Their modular and customizable design supports efficient installation and flexible performance for municipal and industrial gravity filters.
Establishment: 1904
Headquarters: New Brighton, Minnesota, USA
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Company Profile:
AWI Filter (Anthratech Western Inc.) is a specialized manufacturer of granular media filtration solutions for water and wastewater treatment, serving municipal and industrial markets since the late 1970s. Originally founded in Calgary, Alberta, AWI combines expertise in filter hydraulics and granular media design to improve performance and longevity of filtration systems. The company works closely with engineers and plant operators to deliver custom, optimized solutions that enhance overall treatment efficiency and operational outcomes.
In the underdrain filter segment, AWI is widely recognized for its Phoenix™ underdrain systems and panel solutions, engineered for reliable air and water distribution and consistent filter performance. AWI underdrains are custom-designed for each application to ensure uniform backwash flow and collection across the filter bed, supporting longer filter run times, reduced backwash water usage, and easier retrofit upgrades to existing systems. AWI also provides comprehensive technical support, media services, and filter optimization programs that help facilities achieve sustainable filtration performance.
Establishment: 1977
Headquarters: Calgary, Alberta, Canada
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Orthos Liquid Systems, Inc. is a specialized American manufacturer of nozzle-based filter systems and filtration products for water and wastewater treatment applications. Founded in 1984, Orthos has built a strong reputation over 40+ years for delivering reliable, high-quality filtration equipment and underdrain systems across municipal and industrial markets. Based in Bluffton and Ridgeland, South Carolina, Orthos serves water utilities and treatment facilities throughout North, South, and Central America, supporting critical media filtration processes with robust engineering and customer-focused service.
In the underdrain filter segment, Orthos is best known for its Centurion™ monolithic filter underdrains and broad range of nozzle and accessory products that ensure uniform air and water distribution, effective backwash performance, and long service life. Orthos underdrains exhibit exceptional resiliency and low maintenance—no reported underdrain failures in decades of installations—offering utilities reduced lifecycle costs and improved filtration efficiency. The company also offers advanced configurations such as stainless steel free-flow underdrains and customizable nozzle solutions to meet specific project requirements.
Establishment: 1984
Headquarters: Bluffton, South Carolina, USA
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WesTech Engineering is a U.S.-based leader in water and wastewater treatment equipment, serving municipal, industrial, and process water applications worldwide since its founding in 1973. The company, part of Swire Water, focuses on designing, engineering, and manufacturing a broad range of treatment solutions that help communities improve water quality, optimize processes, and meet regulatory requirements. With ISO 9001 certification and an emphasis on responsive service, WesTech’s systems are widely used for liquid-solids separation, clarification, filtration, and other critical treatment steps.
In filtration and underdrain systems, WesTech provides engineered solutions such as MULTIBLOCK® filter underdrains and integrated pressure filter designs that ensure uniform air and water distribution across media beds. These underdrains offer superior media retention, corrosion-resistant construction, reduced installation complexity, and effective backwash performance. WesTech’s filtration products are designed to improve filter run times, reduce operational costs, and support reliable performance in both gravity and pressure filter configurations, making them well suited for surface water, groundwater, and industrial process water treatment.
Establishment: 1973
Headquarters: Salt Lake City, Utah, USA
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Roberts Filter Group is a historic American water filtration company with roots dating back to 1889, making it one of the longest-standing names in the global water treatment industry. Headquartered in Pennsylvania, USA, the company has designed and manufactured advanced filtration systems used in municipal, industrial, and environmental applications worldwide. Roberts Filter Group combines over a century of engineering experience with ISO 9001-certified manufacturing to deliver reliable solutions that help communities and industries meet critical water quality and regulatory goals.
In the underdrain filter market, Roberts Filter Group offers a broad portfolio of proven underdrain technologies designed to maximize performance and durability. Flagship products include the Trilateral® SST stainless steel underdrain, the Infinity® continuous lateral unibody underdrain, and heritage systems such as clay tile and Wheeler bottom underdrains. These systems provide uniform air and water distribution, enhanced backwash effectiveness, and long service life—supporting efficient filter runs, reduced maintenance, and dependable operation in gravity and pressure filtration applications around the world.
Establishment: 1889
Headquarters: Coatesville, Pennsylvania, USA
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Veolia Water Technologies is the water and wastewater treatment division of the global environmental services leader Veolia Environnement, and a major provider of sustainable treatment solutions for municipal and industrial applications worldwide. With roots dating back to the 19th century as part of Compagnie Générale des Eaux and now operating across dozens of countries, Veolia delivers advanced technologies and engineering support that help utilities and industries meet stringent water quality standards and optimize filtration performance.
Within its filtration portfolio, Veolia offers engineered underdrain solutions and integrated filter systems that ensure uniform air and water distribution in media beds and support efficient backwashing. Products such as the MNF underdrain concrete systems and heavy-duty underdrain nozzle designs excel in providing structural rigidity, high nozzle density, and thorough media cleaning, reducing installation complexity and lifecycle costs. These underdrain systems are suitable for drinking water, advanced wastewater treatment, and industrial filtration needs.
Establishment: 1853
Headquarters: Paris, France
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Company Profile:
SUEZ is a French-based global water and wastewater management company with over 160 years of industry experience and operations in more than 40 countries. The company offers comprehensive water treatment, infrastructure design, and environmental solutions to municipal and industrial clients worldwide, helping improve water quality, enhance resource efficiency, and support long-term sustainability. SUEZ’s water treatment expertise includes advanced filtration technologies that form an essential part of modern treatment trains for drinking water and wastewater applications.
Within its broad filtration portfolio, SUEZ provides engineered media filtration solutions and associated underdrain distribution systems that ensure uniform air and water flow through filter beds and support effective backwash performance. These underdrain components form part of SUEZ’s larger treatment system offerings, designed to improve filter run times, increase media life, and deliver consistent solids removal performance in surface and wastewater filtration applications.
Establishment: 1853
Headquarters: Paris, France
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Company Profile:
Weilan Water Treatment Technology Co., Ltd. (Weilan) is a China-based manufacturer specializing in innovative water and wastewater treatment equipment, with a strong focus on filtration solutions for municipal, industrial, and commercial applications. The company provides engineered systems and components that help facilities achieve higher water quality, operational efficiency, and cost-effective performance. With a commitment to research and customization, Weilan serves markets around the world with a wide range of treatment technologies designed to meet diverse project needs.
In the underdrain filter category, Weilan is known for its reliable and customizable underdrain filter systems designed for granular media filtration beds. Weilan underdrains are engineered to ensure uniform distribution of air and water during filter runs and backwash cycles, improving filtration efficiency and extending media life. The company also offers modular designs, high-precision distribution components, and tailored solutions that support reduced maintenance, optimized water usage, and improved filtration performance in municipal and industrial treatment plants.
Establishment: 2003
Headquarters: Henan, China
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The global demand for high-performance underdrain filter systems continues to grow as municipalities and industries pursue higher water quality, lower operating costs, and longer filter service life. The manufacturers listed above represent some of the most trusted names in the industry, offering advanced air and water distribution technologies, durable construction materials, and proven filtration performance for gravity and pressure filters.
When selecting an underdrain filter manufacturer, factors such as engineering expertise, customization capability, product reliability, and technical support are critical to long-term operational success. For projects requiring flexible design, dependable performance, and competitive solutions, Weilan Water Treatment Technology Co., Ltd. stands out as a reliable partner in delivering efficient and cost-effective underdrain filtration systems worldwide.
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