In response to the public health threat from rising nitrate-nitrogen levels in increasing numbers of public supply wells, MassDEP developed this planning tool to assess how land use development decisions impact water quality at the well in a MassDEP-approved Zone II (hydrogeologically defined recharge area to the well). The model is also useful for complying with Groundwater Source Approval Regulations, 310 CMR 22.21, and the State Environmental Code, Title 5, 310 CMR 15.216, in determining flexibility of septic system density requirements within water supply areas.

The user-friendly model, computerized by our contractor, Horsley and Witten, Inc., is stand-alone software originally written for IBM-compatible computers operating on a DOS system. Minimum 640K RAM is needed with 350K resident memory storage. This is a DOS application; no other software is required except a "zip" utility to extract the files. 

Please note: this application may not work in 64-bit operating systems (Windows 7 or later).

The Nitrogen Model documentation package is composed of:

  • the MassDEP Zone II Nitrogen Loading Model
  • a guidance document that describes how the model fits into the regulatory framework

Download ZIP file: MassDEP Nitrogen Loading Computer Model  zip format of MassDEP Nitrogen Loading Computer Model

For further information please contact Steve Hallem, DWP, at or call 617-292-5681.