• City of Tacoma QA
  • City of Tacoma OpenData

Permeable Pavement Specifications

NEW: Download Permeable Pavement Specifications from WSDOT    

The specifications were reviewed by APWA-WA Construction Materials Committee, and the specifications have now been integrated into the Local Agency GSPs!


Solutions with Permeable Pavement

Permeable pavements are a cost-effective solution to managing stormwater when replacing failed roadways. In the last ten years, the City of Tacoma has constructed approximately 30 blocks of permeable pavement and five acres of permeable parking lot. Those projects have shown that while technology is advancing rapidly, the lack of industry standards is slowing progress.


Task Force

Industry standards are vital to the long-term success of permeable pavements in the region. To establish specifications, Tacoma formed a task force of experts from across the spectrum in permeable pavement design and construction.

Subgroups studied porous asphalt, pervious concrete, and subgrade and subbase to finalize specifications. The task force reached consensus on these specifications, recognizing that changes will be needed as technology advances.

The specifications were developed by these experts:

Porous Asphalt

  • Lead – Tim Horton, Skillings Connolly
  • Dave Gent, Washington Asphalt Pavement Association
  • Mark Palmer, City of Puyallup
  • Jessica Knickerbocker, City of Tacoma
  • Dave Bell, Lakeside Industries
  • Chris Pederson, CTL
  • Mark Russell and Jim Weston, WSDOT
  • Kevin Kelsey, King County
  • Mark Davies, SvR

Pervious Concrete

  • Lead - Kathy Gwilym, SVR and Seattle Public Utilities GSI Program
  • Andy Marks, PSCSC
  • Bruce Chattin, WACA
  • Keith Muhich, Miles Resources
  • Dawn Anderson, Pierce County
  • Steve Read, Seattle Public Utilities
  • Mark Russell and Jim Weston, WSDOT
  • Jessica Knickerbocker, City of Tacoma

Subbase and Bases

  • Lead – Matt Miller, AESI
  • Kevin Lamb, GeoDesigns
  • Robin Kirschbaum, HDR
  • Jessica Knickerbocker, City of Tacoma

Future Development in Permeable Pavements

Google Group was established for people interested in permeable pavements. This site will be a venue to announce upcoming paving projects and to ask questions. 



NEW: The specifications were reviewed in November 2015 by APWA-WA Construction Materials Committee Specifications and have been updated. They have also been forwarded to WSDOT for review.


About These Specifications

These specifications are provided as an informational guide by the Permeable Pavement Specifications Task Force. It is still the responsibility of the licensed engineering professional to design the contract documents.