Filterra® Bioretention

Filterra® Bioretention

Filterra is similar to bioretention in its function and application, but has been optimized for high volume/flow treatment and high pollutant removal. Its small footprint allows it to be used on highly developed sites such as landscaped areas, parking lots and streetscapes. Filterra is exceedingly adaptable and can be used alone or in combination with other BMPs.

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How Filterra Works

Stormwater runoff enters the Filterra system through a curb-inlet opening or pipe and flows through a specially designed filter media mixture contained in a landscaped concrete container. The filter media captures and immobilizes pollutants; those pollutants are then decomposed, volatilized and incorporated into the biomass of the Filterra system’s micro/macro fauna and flora. Stormwater runoff flows through the media and into an underdrain system at the bottom of the container, where the treated water is discharged.

Filterra Features and Benefits

Features Benefits
High media flow rate (up to 175" per hour) Reduced footprint compared with traditional bioretention

Third party field testing confirmed that Filterra meets state regulatory requirements for pollutant removal under TAPE and TARP testing

Regulatory Compliance

Filterra offers the most cost effective stormwater treatment system featuring low cost, easy installation and simple maintenance


Landscaping enhances the appearance of your site making it more attractive while removing pollutants

Adds aesthetic appeal to your site

Available in multiple configurations and sizes

Flexibility to meet site-specific needs

No confined space access, and activation is included with the purchase of every system

Simple and easy maintenance


Filterra Media – Proven Pollutant Removal

At the heart of all Filterra systems is Filterra engineered media; a specified gradation of washed aggregate and organic material homogeneously blended under strict quality controlled conditions. The filter media has been optimized to operate under high flow rates (up to 175 inches/hour) while maintaining pollutant removal performance. Filterra media is tested for hydraulic functionality, fertility, and particle size distribution to ensure uniform performance.

Pollutant Median Removal Efficiency Median Effluent Concentration (mg/L) Third Party Reference Studies
Total Suspended Solids 86% 3.3 UVA 2006, Herrera 2009, Herrera 2014, NC State 2015
Total Phosphorus (TAPE) 70% 0.05 Herrera 2014, NC State 2015
Total Nitrogen 34% 0.54 NC State 2015
Total Copper 55% 0.004 UVA 2006, Herrera 2009
Dissolved Copper 43% 0.003 Herrera 2009
Total Zinc 56% 0.04 UVA 2006, Herrera 2009, NC State 2015
Dissolved Zinc 54% 0.1 Herrera 2009
Total Petroleum Hydrocarbons 87% 0.71 Herrera 2009

The information above is based on results from third-party field studies following industry-recognized protocols such as TAPE and TARP. Relevant studies are noted for each pollutant, and corresponding data was aggregated to provide realistic and repeatable performance expectations.

Some jurisdictions recognize higher removal rates - see your Contech Stormwater Consultant for performance expectations.

Select Filterra Approvals

Filterra is approved through numerous local, state and federal verification programs, including:

  • New Jersey Department of Environmental Protection (NJ DEP) 
  • Washington Department of Ecology (GULD) – Basic, Enhanced, Phosphorus, and Oil
  • Maryland Department of the Environment - Environmental Site Design (ESD)
  • Texas Commission on Environmental Quality (TCEQ)
  • Virginia Department of Environmental Quality (VA DEQ)
  • Maine Department of Environmental Protection (ME DEP)
  • Atlanta, GA Regional Commission
  • Los Angeles County, CA - Alternate to Attachment H
  • City of Portland, Oregon Bureau of Environmental Services
  • North Carolina Department of Environmental Quality (NC DEQ)


  • Inline
  • Offline
  • Peak Diversion
  • Bioscape Vault
  • Filterra Bioscape
  • Custom Configurations

Filterra Installation and Maintenance

We make it easy for you...

  • Vegetation selection guidance based on your climate zone.
  • Activation is included with every system
  • Ongoing maintenance is simple.
  • Clean biofiltration bay with simple landscape tools (rake and shovel).
  • No confined space entry required.
  • Everything can be accessed from the surface

Technical information for this product is located in the technical guide’s section. 

View Technical Information
Filterra Offline

The Filterra Offline configuration is the most economical and simplest Filterra configuration. It utilizes a downstream catch basin or curb inlet for bypass flows allowing for the shallowest profile and most flexible design of any of the Filterra configurations. It is ideal for both new and retrofit projects.

Filterra Peak Diversion

The Filterra Peak Diversion provides treatment and high-flow bypass in one structure, eliminating the need for an external bypass structure. This configuration also allows for multiple inlet options, including curb inlets, pipe inlets, and grate inlets.

Filterra Internal Bypass Curb

The Filterra Internal Bypass Curb incorporates a curb inlet treatment chamber and internal high flow bypass in a single structure. This eliminates the need for a separate bypass structure and enables placement in a “sag” or “sump” condition.

Filterra Sediment Chamber (Maryland only)

The Filterra Sediment Chamber includes a pretreatment sediment chamber that provides a settling area for large debris and sediment prior to water entering the media bay.

Filterra Bioscape Vault

The Filterra Bioscape Vault utilizes an open top configuration and downstream catch basin or curb inlet for bypass flows allowing for a shallow profile. Internal Bypass configurations are also available in some locations.

Filterra Bioscape Vault Basin

The Filterra Bioscape Vault Basin allows for a vault based system to be fully integrated into the landscape. Multiple inlet options are available via the side slopes, including sheet flow. Bypass is typically achieved via an upstream structure.

Filterra Bioscape

The Filterra Bioscape utilizes all of the Filterra components, but without the concrete structure, allowing for multiple inlets and installation directly into a basin. Bypass is achieved via an upstream structure.

The Contech Advantage

Agency/Regulatory Guidance

Our team is ready to provide you with expert advice and assistance on local regulatory requirements, resulting in faster approvals.


Solution Development

Our engineers can review your requirements, weigh all options, and recommend the optimal solution to integrate with your site designs.

Technical Expertise

Our engineers can assist by providing product specific engineering calculations such as hydraulics, buoyancy, foundation reactions, and unit sizing.

Cost Estimates

We can quickly provide engineer’s cost
estimates to assist with your solution
selection process.

Site Specific Drawings

Our engineers can provide site-specific drawings for proposals, project meetings, and submittals, helping you be more efficient with your time.

On-site Assistance

Contractors know time is money, so we provide preconstruction meetings, delivery coordination, and on-site installation support to ensure a timely, smooth installation.