Rainwater Filtration Joint for Concrete (whether decorative or traffic-loading) Surfaces

As a Sustainable Drainage System (SuDS), the d-Rain Joint™ is a simple, low-cost, and robust onsite stormwater management alternative compared to other permeable, pervious surface options.

The d-Rain Joint™ device directs the surface rainwater to an installed drainage bed beneath the impervious, “hardscape” surface(s). Using low-cost, harder substrate, the solution to provide a permeable, pavement system (PPS) can be used wherever stormwater management requirements are needed for a driveway, parking lot, garage, large patio, community common areas and streets, pool areas, sports architecture, shopping or theme park developments, alleyways or public walkways. 

The use of traditional concrete with the d-Rain Joint™ provides both permeability AND filtration with lower maintenance at a lower installed cost than a paver system!  These d-Rain Joint™ devices allow the use of traditional concrete or other paver-type materials to construct a high-performing permeable, pervious surface system to put filtered rainwater in the underneath gravel detention area of the pavement; thus, increasing the usable surface, eliminating costly stormwater infrastructure or potential pollution hazards to urban ecosystems.

Rainwater Filtration Device Products include:

      • d-Rain Joint™ 6061-T6 (aluminum), <1” wide and available in 8’ lengths
      • NEW!  d-Rain Joint™ PPIC (gray plastic), <1” wide and available in 8’ lengths (introduced at GreenBuild 2016)

Easy to install like a standard expansion joint and virtually undetectable between concrete slabs, the ADA-compliant d-Rain Joint™ 6061-T6 (aluminum) and the new d-Rain Joint™ PPIC (flexible plastic) channel-inserted filter captures sediment to ensure it’s continued effectiveness of the system at a maximum rate of 5 GPM/linear foot.

The product is highly durable and gives stormwater a path to a subsurface drainage bed. This provides an outlet for surface water to be directed to a drainage bed and collected and held or allowed to percolate back into the soil to conform to environmental conservation and protection requirements.

The d-Rain Joint™ PPIC Device is stackable to 4”, 6”, and 8” height from patio installations to heavy-traffic pavements.

Advantages of the d-Rain Joint™

      • Cost-effective. Adds nominal costs to standard pour-in-place surfaces.
      • Easy installation. Installs using standard practices and equipment.
      • Low-maintenance. Simply clean or replace the filter.
      • Immediate storage capacity. With aggregate type/depth tailored to local needs.
      • Strength and durability. Safe for heavy vehicles and snow removal.
      • Treats stormwater onsite. Environmentally sound option to contain runoff onsite.

We can assist you with (Typical 16’ x 24’sizing and custom designs) Driveway Calculations*. HAVE A PROJECT? Please e-mail your inquiry to

  • to calculate the performance of the permeable driveway system, we start with the square footage of the driveway and typical rainfall statistics for the location of the project.
  • Final Performance Calculation will be dependent on the void-to-solid ratio of the stone gravel bed available and absorption rates of the soils in the local geographic area.
  • If using asphalt, other installation considerations and procedures may be necessary.

How the d-Rain Joint™ Benefits You

Stormwater runoff is a major cause of water pollution in urban areas. When rain falls on our roofs, streets, and parking lots in cities and their suburbs, the water cannot soak into the ground as it should. Stormwater drains through gutters, storm sewers, and other engineered collection systems and is discharged into nearby water bodies. The stormwater runoff carries trash, bacteria, heavy metals, and other pollutants from the urban landscape. Higher flows resulting from heavy rains also can cause erosion and flooding in urban streams, damaging habitat, property, and infrastructure.

When rain falls in natural, undeveloped areas, the water is absorbed and filtered by soil and plants. Stormwater runoff is cleaner and less of a problem. Green infrastructure uses vegetation, soils, and other elements and practices to restore some of the natural processes required to manage water and create healthier urban environments. At the city or county scale, permeability is required for hardscaped and impervious (concrete) surface area to prevent flooding stages and alleviate the strain on storm drain networks. At the neighborhood or site scale, stormwater management systems that allow permeability to “drain the rain” to local aquifers and groundwater sources are an ecologically and economically responsible solution.

How the d-Rain Joint™ Benefits You

      1. Reduces the size of, and need for, retention ponds.
      2. Retains and filters water onsite.
      3. Little to no added water in the stormwater system.
      4. System and product can meet most site design requirements.

Homebuilders and Remodelers.
The d-Rain Joint™ is simple and cost-effective to spec and install. It offers a simple way to adhere to stormwater runoff requirements.

Concrete Suppliers and Contractors.
The d-Rain Joint™ can be installed during the form and pour process by utilizing standard equipment, tools, and procedures.

HUD/Government. The d-Rain Joint™ offers an ecologically and economically responsible solution.

Homeowner. The d-Rain Joint™ uses standard tools and installation procedures, giving homeowners a simple, green alternative for hard surfaces. Very little maintenance is required.

Commercial/Industrial/Institutional. The d-Rain Joint™ can easily be applied to commercial applications offering the benefits of permeable drive and park areas for less cost.

AIA Architect/Landscape Architects. Because the d-Rain Joint™ has a similar visual impact to the standard expansion joint, it offers an eco-friendly solution with little to no visual impact on the overall design.

Engineer/Surveyor. The d-Rain Joint™ uses simple, standard computations for determining stormwater storage and filtration solutions.

Municipality Planners. The d-Rain Joint™ is an eco-friendly, cost-effective solution for solving stormwater runoff issues.

Technical Downloads

d-Rain Joint™ Product Brochures

d-Rain Joint™ Manuals & Test Data

d-Rain Joint Installation & Service Manual d-Rain Joint™ Installation & Service Manual (under review; email: for assistance)

d-Rain Joint™ Drawing and Specifications

Unit Size File Type
d-Rain Joint™ PDF


Get AcrobatAdobe Reader

PLEASE NOTE: In order to open the zipped CAD version, you must have zip compression software, such as WinZip or QuickZip. In order to view the CAD (.dxf) file, you must have installed CAD viewing software, Release 12 or newer. The PDF format can be viewed by installing Adobe Acrobat Reader (4.0 or newer). Click on the images to the right to download either Adobe FREE Acrobat Reader or QuickZip.


Case Studies


[INTERVIEW] IBS Video: new concrete joint manages storm water runoff | Feb. 9, 2016
Storm water management gets easier with a new alternative to permeable concrete solutions.

At the 2016 International Builders’ Show, Brooke Edwards, sales engineer for BioMicrobics, reviewed the company’s new d-Rain Joint™ product that provides a cost-effective method for creating permeable, pervious surfaces.

It was developed to satisfy a permeable, pervious driveway  requirement while addressing LEED and NAHB green building guidelines. It has a moderate installation cost and a very low life cycle cost compared to other permeable, pervious surface options. It’s simple and unique design allows the use of traditional concrete, asphalt or paver materials to construct a highly performing, permeable, pervious surface system and provide groundwater recharge opportunities.

Advantages of the d-Rain Joint™

      • Cost-effective – Adds nominal costs to standard pour-in-place surfaces.
      • Easy installation – Installs using standard practices and equipment.
      • Low-maintenance – Simply clean or replace filter.
      • Immediate storage capacity – With aggregate type/depth tailored for local needs.
      • Strength and durability – Safe for heavy vehicles and snow removal.
      • Treats stormwater onsite – Environmentally sound option to contain runoff onsite.

View Article on ProudGreen Home:

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Product Certifications

Our products are certified to the highest national and international standards in our industry. If you require additional certification marks, etc, please e-mail your request to

USA and International Product Certifications

The list below is a summary of a few certifications received for the products of BioMicrobics:

  • PIA2016-1601-1005 hydraulic testing specific infiltration rates (Pruefinstitut fuer Abwassertechnik GmbH) according to German requirements for stormwater products.
  • P16-0028 Validation Testing, Advanced Manufacturing Institute, Kansas State University

Independent Third-Party Testing for other Systems

Verification programs/locations in which BioMicrobics installed a Wastewater Treatment System for analysis of performance:

  • Massachusetts Title 5 General Use – The first system described as an “Innovative and Alternative (I/A) System” to received the General Use Approval rating for Nitrogen Reduction
  • Florida OWNRS (Onsite Wastewater Nitrogen Reduction Study) Phases I and II
  • New Mexico State/New Mexico University
  • University of Rhode Island
  • Buzzards Bay, MA
  • Ventura County, CA
  • US EPA Environmental Technology Verification Program (ETV), B.C., Canada
  • La Pine, OR
  • Burnette, WA
  • NSF International testing and evaluation for Standard 40, 245, and 350

Recent Business and Technology Awards


  • 2017 North American “Integrated Water Treatment Technology Leadership” Award, Frost & Sullivan
  • 2017 Top 10 Green Building Products, BuildingGreen, Inc.- d-Rain Joint™ Device
  • 2016 President’s “E Star” Award * 2012 President’s “E” Award for Excellence in Exports, granted by President of the United States, presented by US Dept of Commerce
  • 2015 Ingenuity Award Winner, Ingenuity Central @ K-State Olathe, Ingenuity Central (IC) showcases innovative companies that exemplify the newest thinking driving our community & growing our economy.
  • 2015 Innovation in Marine Environmental Technology Offshore Excellence Award, based on environmental impact with marine sanitation devices and technology.
  • 2014 “BEST of GreenBuild” Editor’s Choice Award, U.S. Builder’s Review, “Creating Better Water Treatment Solutions for a Better World…“article.
  • 2012 President’s “E” Award for Excellence in Exports, granted by the U.S. President, presented by the U.S. Department of Commerce
  • 2011 Kansas Governor Exporter of the Year, presented by the Governor of Kansas
  • 2011 North American Technology Innovation Award (Decentralized Commercial Outlets) – Frost & Sullivan
  • 2011 New Product of the Year Award (Recycling) – BioBarrier® MBR System – Environmental Protection (EPOnline)
  • 2010 North American Technology Innovation Award (Water/Wastewater) – Frost & Sullivan
  • 2009 Exporter of the Year Award, Environmental – ThinkGlobal / Commercial News USA (Official publication of the U.S. Dept. of Commerce)
  • 2009 Technology Merit Business Achievement Award, Water/Wastewater – Environmental Business Journal (EBJ)
  • 2002 U.S. Export Achievement Certificate, US Dept. of Commerce, US & Foreign Commercial Service
  • 2000 U.S. EPA Environmental Technology Innovator Award – U.S. EPA, Region 1 – SeptiTech® Technology