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Information about how to purchase WinSLAMM.

Links to order forms for credit card, and non-credit card purchases.

Tax information and license renewal policy.


Instructions for how to download and install WinSLAMM after purchasing the program.

Includes download links for WinSLAMM versions 9.4.0, 10.5.0 and a trial version of WinSLAMM 10.4.0


An archive of past training materials for the WinSLAMM program.

Resources to schedule training for your company on WinSLAMM software.

Program reference PDFS, and dates and locations of past training events.


WinSLAMM was developed to better understand the relationships between sources of urban runoff pollutants and runoff quality.

Click here to meet the team behind WinSLAMM!


  • WinSLAMM Version 10.5.0 released! (posted 12/14/2022)


PV & Associates, LLC is a small business that develops the urban water quality software program - WinSLAMM. The program is continually updated as new research data becomes available.

The program was originally developed as outgrowths of early stormwater research conducted during the 1970s for the US EPA and other agencies. We realized that the monitored data did not correspond to many assumptions that were the basis for available stormwater quality models, and therefore decided to create a program that better reflected research results and was more focused on stormwater quality management than on drainage design.

Model development is supported through software sales and has also been supported by organizations such as the Environmental Protection Agency (EPA), Ontario Ministry of the Environment, Environment Canada, Wisconsin Department of Natural Resources (WDNR) and the United States Geological Survey (USGS). For a complete list of organizations that have supported model development, see the WinSLAMM History page on this website.


Current Release: v10.5.0

WinSLAMM (Source Loading and Management Model for Windows) is the only Urban Stormwater Quality Model that evaluates runoff volume and pollution loading for each source area within each land use for each rainfall event. It does not lump impervious areas together nor does it lump all the areas in a single land use together. Evaluation at the source area level allows stormwater quality professionals the ability to target the highest loading areas and recommend improvements to reduce runoff volume and pollution loading from those areas.

WinSLAMM is the leading model for evaluating LID Practices and Green Infrastructure. USEPA's definition of Green Infrastructure is "systems and practices that use or mimic natural processes to infiltrate, evapotranspirate (the return of water to the atmosphere either through evaporation or by plants), or reuse stormwater or runoff on the site where it is generated." WinSLAMM the only model that evaluates stormwater pollution at the source area level - were runoff is generated.

WinSLAMM utilizes small storm hydrology - the concept that the majority of the runoff volume and pollutant loadings in urban areas is a result of the small and medium rainfall events.

WinSLAMM can model a growing list of stormwater control measures including infiltration/biofiltration basins, street cleaning, wet detention ponds, grass swales, filter strips, porous pavement, catchbasins, water reuse, and various proprietary devices.

WinSLAMM can be used to answer questions such as:

  • How effective are stormwater control measures in reducing runoff and pollutant loadings?
  • What are the most cost-effective solutions for meeting urban stormwater quality objectives?
  • What type of, and how big should, stormwater control measures be?

Since its origination in the 1970's, the program's use has extended across North America and overseas. WinSLAMM is based largely upon Dr. Robert Pitt's research studies conducted in the United States and Canada and by research studies conducted through the WDNR and the USGS.

Various practitioners, municipalities, and watershed groups at the regional and local level have used WinSLAMM to address a variety of urban stormwater issues:

  • Developing TMDL implementation plans
  • Identifying management practices to achieve pollutant reductions under a municipal separate storm sewer system (MS4) stormwater permit
  • Determining optimal green infrastructure strategies for reducing volume and peak flows to combined sewer systems
  • Evaluating site specific post-construction stormwater management designs
  • Developing a phased BMP installation plan using the cost effectiveness curve

Because the majority of WinSLAMM development is not funded by grants, the improvements and support do not stop when the grant runs out. This means the user will always have access to help when its needed.