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Minimal Industrial Discharge

Obtaining the Permit (State)& Letter of Authorization (City)

Step #1 Do you need a permit?

Contact the CDPHE at 303-692-3500.

Step #2Obtain Longmont

"Letter of Authorization"

General Information


Local Concerns

Stormwater Quality Program
1100 S. Sherman Street
Longmont, CO 80501
Phone: (303) 651-8667
or email:

The State allows water from some operations (no cleaning solutions or contaminants) to be discharged to state waters if a point source permit is obtained. Fees apply. If the discharge is made to the City's storm drainage system, you must obtain letter of authorization from the City of Longmont. There is no fee for the letter of authorization.

Save $$ and Click here first to read more about the local concerns and requirements about this permit program. The best option still is to collect the wastes and dispose to the sanitary sewer on-site with permission from the City's IP Program and site owner.

More information available on-line about Storm Drain Prohibitions and Exemptions.


General Information about the "Letter of Authorization"


Wastewater from minimual discharge industrial operations that does not contain soaps, chemicals or pollutants may be discharged to the storm sewer only if:


  1. Complete an application (pdf). You must fill it out, sign and print. If you cannot download this pdf, call 303-651-8667 to obtain hard copy or electronic copy (specify pdf or doc). Do not leave any blanks; use "not applicable". There are no application fees at this time. Submit completed form with original signatures to:

    Storm Water Quality Program- WWTP

    501 East 1st Avenue

    Longmont, CO 80501
    Copies, faxes and electronic versions are not accepted

  2. Upon approval, the City will provide a letter of authorization. The permission expires in 90 days or when the State Permit expires, whichever comes first.
  3. To renew the permission, the applicant must submit a renewal application (pdf) to the above address.

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CDPHE Permit Applicable to Discharges from:

Contact the CDPHE at 303-692-3500 as the criteria is currently being re-evaluated.

Other Concerns


The State permit is required only if the wastes can enter the state waters directly or via a storm drainage system. If the water is discharged to the landscaping and can in no way enter the storm drain or State waters (that is, it evaporates), the discharge is not considered a "point source" and a permit is not required.

oily discharge to ground





Snow removed from fueling pad and parking lot contained oil/fuel. It was piled in this location.

The snow melted and the oily wastes soaked into the ground and entered retention pond on site.

Wastes had potential to leave site = "threatened discharge".



A "threatened discharge" is defined by the Longmont Municipal Code as any discharge of contaminants that could leave the site. (An "illegal discharge" is one that actually leaves the site.) Therefore, any discharge of wastes to landscape that contains contaminants is a violation of the Municipal Code. These have the potential to leave the site during the next rain storm. The State process indicates that you do not need a permit for discharges that don't enter the storm drain, but fails to inform you of the potential violations if the wastes contains any contaminants.



Collect the wastes and discharge them to the sanitary sewer on-site. Contact the IP Program at 303-651-8667.

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Stormwater Program|Water Utilities|Public Works & Natural Resources|City of Longmont

This page was updated August 19, 2013
City of Longmont Public Works & Natural Resources
Stormwater Quality Program

Pollution Prevention Program