AZ Pollution Discharge Elimination System



  • Environmental Specialist
  • 433 N Virginia St

  • 928-777-1130


  • Stormwater
  • 928-777-1651

Watson Lake and Upper Granite Creek Watershed Pollution Reduction Plans completed

The City of Prescott recently finalized management plans for water quality improvements in Watson Lake and the watershed that feeds it.  Those documents are linked below.  If you have any questions or comments about them we’d be happy to discuss them, email us.

Watson Lake Reservoir Management Plan

Upper Granite Creek Watershed Pollutant Reduction Plan

How Do We Improve Watson Lake’s Water Quality and At What Cost?

The City of Prescott is seeking public input on its Stormwater Management Plan.

This plan is the guiding document for compliance with Arizona Department of Environmental Quality’s Municipal Separate Storm Sewer System (MS4) permit.  This originates from the federal Clean Water Act legislation and details the steps the City is taking to reduce the pollutants entering our creeks and lakes.

A core component of the SWMP are the 6 Minimum Control Measures (MCMs), they are as follows:

  • MCM1: Public education and outreach
  • MCM2: Public  Involvement
  • MCM3: Illicit Discharge Detection and Elimination
  • MCM4: Construction
  • MCM5: Post- Construction
  • MCM6: Good Housekeeping

Your input will help us tailor these MCMs to better reflect our community and its needs.

The 2022 SWMP may be found here.  Stormwater personnel would be happy to discuss this with you via email or phone (928-777-1130). 

City Stormwater staff will also provide an in-person Stormwater Management Program presentation on June 29th from 5:30 PM- 6:30 PM in the Public Works Conference Room located at 433 N. Virginia St. 

A significant amount of that time will be set aside for Q&A and to document YOUR ideas for improvement.  Thanks!

We welcome your comments and ideas on how to better protect the City’s surface waters.

For a sense of what the City has done in recent years our annual reports are now posted online for reference. 

The City of Prescott operates a Municipal Separate Storm Sewer System (MS4), which means that the storm sewer and the sanitary sewer are separate systems. The City’s storm sewer system consists of municipally owned streets with drainage systems comprised of a combination of catch basins, curbs, gutters, ditches, manmade channels, and storm drains. Rain, snow melt, and other substances dumped into a street, alley, gutter or storm drain enter the storm drainage system and flow into the nearest creek or lake untreated.

In Arizona, MS4s are regulated by the Arizona Department of Environmental Quality (ADEQ) through the Arizona Pollutant Discharge Elimination System (AZPDES) permit program. In accordance with the AZPDES Small MS4 General Permit, each MS4 is required to prepare and implement a Stormwater Management Program Plan (SWMP). The SWMP must reduce the discharge of pollutants to the “maximum extent practicable”, protect water quality, and satisfy the appropriate water quality requirements of the Clean Water Act. Small MS4s must design into their programs six minimum control measures including: Public Education and Outreach; Public Participation/Involvement; Illicit Discharge Detection and Elimination; Construction Site Runoff Control; and Post-Construction Runoff Control.