Welcome to the City of Flagstaff Stormwater Management website. The
mission of the stormwater section is to promote public health, safety, and general welfare. Our aim is to minimize public and private
losses due to flood conditions within the City of Flagstaff, and to comply with the applicable floodplain and stormwater regulations.
Monsoon Season is Here!
A monsoon is a seasonal shift in wind direction and pressure distribution that causes precipitation change. Large-scale sea breezes occurring over land that is significantly warmer causes the air above it to expand and areas of low pressure develop. The air is cooled in lower pressure and condensation is created.
These rains can cause floods and that's serious business! Click the link below to learn about proper precautions and services provided by the city.
Monsoon Awareness and Flooding
Only Rain in the Drain
Did you know that Flagstaff's storm drain system and sewer system are separate? What goes down the storm drain is not treated at a treatment plant, but flows untreated into the Rio de Flag. Help us protect our local waterways by preventing stormwater pollution. Enjoy this video and remember: Only Rain in the Storm Drain!
Stormwater Credit Manual
The City of Flagstaff has revised the Stormwater Credit Manual. The Manual is a document which provides for discounts on your stormwater billing (as shown on your water bill) for certain stormwater controls such as detention basins, Low Impact Development (LID) facilities and Rainwater Harvesting. Many developments that have occurred since 1990 may be eligible for a discount. The discount may be applied to commercial, industrial or residential developments. As part of the application process, you will need to attest that the facility(s) are maintained on a regular basis by yourself or perhaps by a Homeowner's Association. If you believe you or the subdivision you live in, may have a stormwater facility that may apply, you are encouraged to apply for a discount.
Application ( click here)
To find out if your property may be eligible for a discount, please contact Chris Kirkendall at 213-2473. Please submit the completed application to
or mail to City of Flagstaff Stormwater Management, attn: Chris Kirkendall, 211 W. Aspen Ave., Flagstaff, AZ 86001.
Small Municipal Separate Storm Sewer System General Permit
ADEQ recently issued a new small Municipal Separate Storm Sewer System (MS4) permit, effective September 30, 2016.
This permit is for certain public entities that operate municipal separate storm sewer systems. The permit authorizes the discharge of stormwater to U.S. waters from Small MS4s, which may include a city, town or county located fully or partially within an urbanized area as determined by the latest Decennial Census by the Bureau of Census; state, federal and other publicly-owned properties that discharge stormwater; and other areas designated by ADEQ. The permit requires the development of a stormwater management program. The permittees are required to follow six minimum control measures that must be built into their program including: Public Education and Outreach; Public Involvement and Participation; Illicit Discharge Detection and Elimination (IDDE) Program; Construction Site Stormwater Runoff Control; Post-Construction Stormwater Management; and Pollution Prevention and Good Housekeeping.
The City of Flagstaff requested coverage under the 2016 MS4 by submitting a Notice of Intent (NOI) to ADEQ. ADEQ posted a public notice and proposes to issue Water Quality (AZPDES) Small MS4 General Permit (AZG2016-002) coverage to the City of Flagstaff. The City of Flagstaff is subject to provisions of the Federal Clean Water Act and the requirements of the Arizona Pollutant Discharge Elimination System (AZPDES) program, pursuant to Arizona Revised Statutes (A.R.S) Title 49, Chapter 2, Article 3.1, and Arizona Administrative Code (A.A.C.) Title 18, Article 9.
The City of Flagstaff encourages residents to view the small MS4 general permit and the NOI. Public comments are due to ADEQ by Email or mail (must be postmarked or received) by May 20, 2017. A link to the public notice on ADEQ's webpage is
Links to small MS4 documents:
New Requirements for certain single family Building Permits
Effective January 1, 2015 the Arizona Department of Environmental Quality (ADEQ) will require a Stormwater Construction General Permit (2013 CGP) for certain single family residential units and subdivision infill projects. (See complete list of affected subdivisions in the Fact Sheet link provided below).
Requirements per ADEQ: Construction sites that disturb less than one acre, but are part of a common plan of development or sale that will ultimately disturb one acre or more need CGP coverage. It includes all clearing, grading, excavation, and stockpiling activities that will result in the disturbance of one or more acres. It also includes supporting activities such as storage of construction materials, vehicle and equipment storage and maintenance (e.g., fill piles, borrow area, concrete truck washout, fueling).
This permit is a requirement of the Clean Water Act and administered by the City of Flagstaff in conjunction with the Arizona Department of Environmental Quality (ADEQ). It is a part of the National Pollutant Discharge Elimination System (NPDES) focusing on point source pollutants associated with stormwater runoff.
Links to useful documents and guidelines are below:
2013 Construction General Permit (ADEQ)
Construction General Permit (CGP) Inspection Form
Frequently Asked Questions (CGP)
Notice of Intent (NOI) Fillable Form
SWPPP Plan Sheet Guide