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Rectangular Tanks (T-Max™ Tanks)

water test, rectangular tank, fiberglass tank

Orenco Composites’ rectangular fiberglass-reinforced polymer (FRP) T-Max™ tanks are versatile storage vessels, useful for a myriad of industries and applications. T-Max tanks are molded as a single-piece using vacuum infusion, providing a high-strength seamless vessel. The unique foam-core structural wall design provides integral insulation (R24 or more) and strong, stiff walls — strong enough that T-Max tanks can be buried or sit above ground.

T-Max tanks can be configured with multiple baffles, access covers and hatches, safety railings, and ladders. In addition, tanks can be fully outfitted with slide rail systems, pumping systems, filters, and many other custom internal components. T-Max tanks come fitted with four steel lifting lugs for ease in lifting and placing tanks into place.

Rectangular Tank External Ladder Option, custom railing and ladder

Our T-Max rectangular FRP tanks are often the most cost-effective, long-term solution for many storage requirements, outperforming other materials such as steel and concrete. Orenco Composites manufactures fiberglass-reinforced tanks of varying sizes to meet your project needs, with capacities from 300 gallons to 40,000 gallons. We can also produce rectangular tanks that can be built in place using panel construction. These are typically used on difficult sites — indoor or outdoor — where access and space are limited.

T-Max rectangular fiberglass tanks can be used in a variety of applications, including water and wastewater treatment processes, potable and non-potable water storage, sewage storage, sludge storage, chemical storage, and much more.

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Give one of our technical sales reps a call today. We’ll work closely with you and your team from start to finish. We design the product to meet your specific application needs, and we deliver on time, so you can finish your project on time.


  • From 300 gallons to 40,000 gallons
    (1.1 m³ to 151.4 m³)
  • Standard widths: 7.5′ and 10′
    (2.3 m and 3.0 m)
  • Standard lengths: 7′, 14′, 21′, 28′, 35′, 42′
    (2.1 m, 4.3 m, 6.4 m, 8.5 m,
    10.7 m, 12.8 m)
  • Custom sizes available


  • Corrosion-free
  • Permanent or temporary installation
  • Above-ground or below-ground installation
  • Single-piece, closed-molded vessel
  • Insulated up to R-24
  • Internal tank coatings
  • Varied resins based on application
  • Custom colors


  • Safety railings
  • Ladders
  • Integrated control rooms
  • Access covers and hatches
  • Baffles
  • Slide rail systems
  • Effluent pump and filter systems
  • Open top with grating


  • Potable and non-potable water storage
  • Wastewater storage and settling
  • Sewage storage and primary treatment
  • Water treatment process vessel
  • Wastewater treatment process vessel
  • Sludge storage
  • Chemical storage


Request A Quote!

Fill out our quick and easy quote form, or just give us a call and tell us about your project. We’re happy to provide shelters, basins, tanks, enclosures, or custom built composite parts.

Request a quote from Orenco Composites