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SWAP assessment phase

Lower Platt River under a blue sky

Source water assessment information

We evaluate the origin of each public water system’s source water, identify potential contaminant sources, and assess the susceptibility of each source to contamination. Susceptibility is determined by analyzing both the physical characteristics of the water source’s setting and the potential threats posed by surrounding contaminant sources.

Find your public water system's report.

Please note:

  • Reports do not indicate whether contamination has occurred or will occur.
  • Reports do not reflect the current quality of the untreated or treated water.
  • These assessments serve as a starting point to evaluate potential risks and support source water protection efforts.
  • Some systems have identified historical data inconsistencies; we encourage updates through ongoing protection planning.
  • Search for your system’s report by name or the last six digits of the PWSID. You can also browse reports by county. 

Report overview

Source Water Assessment and Protection Reports provide a summary of the following:

  • Susceptibility of each water source to potential contaminants.
  • Identification of the most prevalent and most threatening contaminant sources.
  • Evaluation of both individual and cumulative vulnerability risks.
  • A total susceptibility rating for each water source indicates the potential cumulative contamination risk to the untreated source water.
  • Total susceptibility rating factors are evaluated for each potential contaminant source, taking into account the size of the source water assessment area.
  • Comparison of each water source’s susceptibility with similar sources across Colorado.
  • Susceptibility ratings are designed to help communities understand risks and guide protection efforts.

Important notes

  • Assessment reports were completed for systems active in the state’s drinking water database as of March 2001.
  • Public water systems or water sources that became active after March 2001 were not assessed and do not have reports.
  • Public water systems that purchase water from another public water system will not have individual assessments. Instead, you will be redirected to the report for the supplying system.
  • Your public water system may have more than one report based on source type (e.g., groundwater vs. surface water).

Assessment methods

We use standardized methods to assess the susceptibility of surface water and groundwater sources. These methodologies are detailed in two separate documents:

Each document outlines the specific approach used to assess those types of water sources, consistent with the methods referenced in your source water assessment report.