Odor Program

For Denver to be more responsive to resident concerns related to persistent odor issues, DDPHE is considering updates to Denver's odor ordinance and regulations. An updated regulation will strengthen the city’s authority to require best available odor control technologies and ensure they are properly installed and operated.

An update to the odor ordinance could include language to allow DDPHE to reopen an Odor Control Plan if:

• Odors are measured that exceed the city’s seven-to-one dilution threshold (as measured by an olfactometer), and/or
• The city receives five or more complaints from separate households or businesses within the City and County of Denver in a 30-day period.

If adopted, these updates may result in:

• Requirements to upgrade odor control technologies, especially if engineering controls are outdated or insufficient.
• Increased financial risk for noncompliance, due to potential penalty increases.

Facilities in compliance with current regulations with well maintained odor control systems should experience minimal changes.

Nuisance odors can be detrimental to the health, comfort, safety or welfare of residents. Denver's Odor Ordinance protects residents’ ability to reasonably enjoy life in the city without interference from strong or persistent odors. 

Outreach to regulated businesses, community groups, and the general public are scheduled through the fall of 2026. Feedback from these efforts will be incorporated into any recommended changes. We anticipate City Council will consider updates to the odor ordinance through the end of 2026. Adoption and development of the DDPHE Board of Health & Environment level regulations are slated for 2027.

Residents can get involved by emailing questions, comments, or concerns to odorrulemaking@denvergov.org.

Residents, business owners and employees can file formal complaints for outdoor odors observed within the City and County of Denver. Odors observed outside of this boundary are generally the purview of another municipality or county government. 

To file a complaint in Denver, call 311 (720-913-1311) or visit 311 online. 

It is a violation if odorous contaminants (the smell) are detected when one volume of the odorous air has been diluted with seven or more volumes of odor-free air.

DDPHE field inspections are performed with an olfactometer (pictured here) to measure the intensity of odors. These devices take air from the open environment an combine it with filtered air to determine the strength of an odor.

Curious about penalties? View DDPHE's criteria(PDF, 751KB) for evaluating violations and assessing civil penalties.

A nuisance odor is defined in Denver’s code as “the doing of or the failure to do something that allows or permits air contaminants to escape into the open air that are or tend to be detrimental to the health, comfort, safety or welfare of the public or that causes or tends to cause injury or substantial annoyance or inconvenience to persons exposed thereto or causes or tends to cause damage to property.”

What does this mean?

Nuisance odors are typically bad smells or air pollutants released into open air, that can make people sick, uncomfortable, or annoyed. 

In Denver, all types of odors can be regulated and odors from commercial facilities that have the following activities are automatically regulated:

• pet food manufacturing
• marijuana growing, processing, manufacturing or consumption in licensed facilities
• rendering and meat by product processing
• asphalt shingle and coating materials manufacturing
• petroleum refining
• sewage treatment
• wood preservation

Denver regulates the emission of odors from various commercial sources such as pet food manufacturing, marijuana cultivation, and animal rendering facilities. For sources that qualify, facilities are required to adopt an Odor Control Plan, which details the implementation of odor control practices and/or equipment. Odor Control Plans are developed by the source facility and approved by the city.   

An Odor Control Plan identifies odor sources and what a facility will do to reduce them, either through installing odor control equipment and/or training employees on job protocols that can reduce odor. The plan is created by a facility and approved by the city. Find resources to create an OCP in Denver. 

OCPs are required by any facility that:

• Receives five or more complaints from separate households or businesses within the City and County of Denver in a 30-day period. (Complaints must be verified by DDPHE.)
• Exceeds the seven-to-one dilution threshold
• Engages in any of the following activities:
  • pet food manufacturing
  • marijuana growing, processing, or manufacturing, or consumption in licensed facilities 
  • rendering and meat by product
  • processing asphalt shingle and coating materials manufacturing
  • petroleum refining
  • sewage treatment
  • wood preservation

The Denver Department of Public Health & Environment (DDPHE) enforces this ordinance and responds to outdoor odor complaints. 

DDPHE field inspections are performed with an olfactometer (pictured here) to measure the intensity of odors. These devices take air from the open environment an combine it with filtered air to determine the strength of an odor.

It is a violation if odorous contaminants (the smell) are detected when one volume of the odorous air has been diluted with seven or more volumes of odor-free air.

Yes. Temporary rodeos, stock shows, tarring operations, and other similar temporary events are exempt.

Residents can submit outdoor odor complaints to DDPHE by calling 311.

Once the complaint is recieved:

• DDPHE inspectors contact the resident via email or phone to gather more information about the odor issue.
• Depending on the issue and if the inspector believes there is a high probability of detecting the odor in the field or a field investigation is helpful, the inspector will visit the location where the odor was detected.
• At that time, the inspector will attempt to identify the odor source and use an olfactometer to determine if the intensity of the odor violates the city’s regulations.