Filter Underdrain Solutions
For more than a century, Roberts Filter Group has led the way in underdrain technology — the foundation of reliable gravity filtration. Our patented systems are designed to deliver uniform flow, efficient backwashing, and long-term durability. Whether you’re building a new filter or upgrading an existing one, Roberts underdrains provide the performance and longevity your plant depends on.
Our Underdrain Technologies
Roberts offers a complete portfolio of underdrain solutions to meet the needs of both new and existing filters. From our flagship stainless-steel Trilateral® SST system to the Infinity® continuous lateral, as well as rehabilitation options for Wheeler bottoms, clay tile, and header-lateral designs, we provide underdrains that deliver dependable flow distribution and decades of service life. Explore our technologies below to find the right solution for your plant.
Trilateral SST
Trilateral® SST is a stainless steel underdrain system built for unmatched strength and reliability. Its rigid stainless-steel construction ensures uniform flow distribution, consistent backwashing, and decades of dependable service.
Trilateral HDPE
A cost-effective, corrosion-resistant alternative to stainless steel. The HDPE design combines structural integrity with flexibility, making it ideal for municipal plants seeking long-term performance with lower capital costs.
Infinity
The Infinity® underdrain features an extruded unibody design that eliminates joints — the weakest point in most underdrain systems. Trusted for decades in municipal and industrial plants worldwide, Infinity® offers long-term reliability with minimal maintenance.
Wheeler Bottom Underdrains
Roberts has been rehabilitating Wheeler bottoms for decades. Our solutions include Retroliners, which balance flow and protect aging underdrains, as well as the option to pour entirely new Wheeler bottoms using modern construction techniques. Both approaches ensure lasting reliability and extend the service life of these legacy systems.
Clay Tile Underdrains
Proven ceramic block underdrains offering uniform backwash distribution, structural strength, and long service life. Still in operation worldwide, Roberts supports both legacy installations and new projects.
Header Lateral Underdrains
For plants with header-lateral designs, Roberts offers both replacement parts and full upgrade solutions. We design retrofits that improve backwash performance and extend system lifespan.
Looking for the right underdrain solution?
From legacy Clay Tile and Wheeler Bottom systems to modern Infinity® and Trilateral® underdrains, Roberts Filter Group has the proven technologies and lifecycle services to keep your filters performing for generations.
Whether you’re building new, upgrading existing filters, or solving underdrain performance issues, our experts can help you choose the best solution — and support it from installation through decades of operation.
