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​  Fiberglass Wastewater Tanks




Underground fiberglass wastewater tanks are ideal for both aerobic and anaerobic septic applications. Fextex supplies watertight tanks that are a cost effective, long-term solution for commercial developments, industrial and municipal applications. Talk to us about your wastewater storage needs, and can help determine the most cost effective, and efficient way to handle your wastewater.

Fiberglass Wastewater Tank
Fiberglass Wastewater Tanks


Fextex helps you design your underground fiberglass wastewater tank so it meets local code, is easily maintained, structured around your budget and fits seamlessly with the rest of your system build out. Fextex can provide custom drawings, buoyancy calculations  dipstick calibration charts, installation manuals, typical application drawings and expert advise. Understanding the intricacies of the whole onsite system allows Fextex to better identify the customer's needs, ultimately saving time and money. 


Fiberglass Wastewater Tank Design
Fiberglass Wastewater Tank Considerations
  • A fiberglass wastewater tank costs around $2- $2.50 per gallon. Full explanation here

  • Combining a septic/dosing tank, recirculation/dosing tank or septic/recirculation/dosing tank into a single multi-function tank will provide overall cost savings.

  • Fiberglass tanks are sized by total volume. To get liquid volume of your tank, use our dipstick calibration chart and the height of the invert of your outlet.

  • Over time the scum layer in your wastewater tank (especially around the inlet) will harden if not pumped regularly. Consider quantity of access openings for future pumping maintainance. 

  • Make sure your outlet is at least the size of your inlet. Drop your tank outlet at least 3" below your inlet. Both of these precautions will help prevent your tank from ever backing up.

  • Make sure the riser opening over your baffle wall (dual compartment tanks only) is at least 30" diameter. This allows man access to both sides of your tank.

  • Consider deep tank burial VS. anti-buoyancy equipment costs. How deep do you have to bury your tank without concrete deadmen, anchorage straps & turnbuckles? Contact us for fiberglass tank buoyancy calculations.



  • Housing Developments

  • Municipalities

  • Public Parks

  • Rural Developments

  • Sanitary Stations

  • RV Parks

  • Resorts

  • Schools

Fiberglass Watewater Tank Applications


  • Easy to ship and Install

  • Rustproof Long Lasting Fiberglass Construction

  • Sizes up to 60,000 Gallons

  • UL 1316 & ANSI/AWWA D120

  • Designed for H-20 Loading

  • Designed W/ Integral Ribs for Added Strength

Wastewater Tank Features
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