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Storm Drainage

The City's Storm Drainage System allows for efficient removal

of stormwater and snow melt from streets and properties. The City has Engineering Projects and

Storm Water Quality Program

Storm Drain Tiles

The Storm Drainage System does not include any treatment system. So, any litter, sediment or pollution on the ground has a potential of getting washed into the storm drain and into the river. Illegal discharges to the storm drainage system are a serious problem.


Storm Drainage

1100 S. Sherman

Longmont, CO 80501

Phone: (303) 651-8376

or email: water


Construction Activity Permits

Stormwater discharges from construction sites and grading are covered under the Construction Activity Permits.  If a Construction Permit is required, it must be obtained prior to any on-site construction activity. 


Construction Activity Permit

Permits- stormwater related


Keeping It Clean


Car Washing

Lawn Care- fertilizers

Scoop the Poop

Spill Clean Up

Yard Wastes - Avoiding Blockages


Food Service BMPs

Mobile Pet Washing BMPs

Power Washing BMPs

Permits- stormwater related

Heat Transfer Equipment Cleaning

Minimum Industrial Discharge


"Keep It Clean Partnership" (KICP)


Illegal and Potential Discharges

The storm drainage system is designed to accept only storm water and snow melt. But, pollution has the ability to enter storm drains, too.

The Municipal Code chapter 14.26 details the prohibited substances that cannot enter the storm drainage system.

An Illegal Discharge is any prohibited substance that leaves the property.

A Potential Discharge is any prohibited substance that has a potential to become an illegal discharge. For example, a leaking dumpster or a bucket of motor oil left in a parking lot.

Municipal Code 14.26

Prohibitions and Exemptions




For emergencies, always dial 911.

For non-emergencies during regular business hours,

call PWWU- Utility Operations - (303) 651-8468 or

Fire Dept HAZARDOUS MATERIALS - (303) 651-8833/(303) 591-9002

For non-emergencies during nights & weekends, call DISPATCH - (303) 651-8501.

For discharges not in Longmont, call Boulder Co. 303-441-1564 or

Colorado Dept. of Public Health Spill Hotline at 1-877-518-5608.



Flood on Main, 1994

To report an area that is flooded during a storm, call 303-651-8416 during regular office hours.

After hours, please call Police Dispatch at 303-651-8501.



Reminder: It is unlawful to alter the flow of water along your curbside, i.e, constructing a ramp to minimize the curb to your driverway. Please ensure leaves do not accumulate in the gutter area. For more information regarding the disposal of leaves, please see the Leaf Collection page.



The City of Longmont collects monthly user charge for operations and services for storm water system. For more information, see the City's Municipal Code, Chapter 14.24 (Storm Drainage).

Storm Drainage System Capital Improvement Fee (a plant investment fee) is assessed to each one-family dwelling building permit issued for residential construction, and is assessed to each residential building permit issued for the construction of expansion of a unit larger than a one-family dwelling. All funds collected by the charge of plant investment fee are utilized only for capital improvements.


Drainage Criteria Manual

Flood Plain Regulations

Engineering Projects

Utility Operations

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

This page was updated August 26, 2013

City of Longmont Public Works & Natural Resources

Storm Drainage