Please note this FAQ pertains to odors related to the Wastewater Treatment Plant. There is also an FAQ about general sewer odors.

Why is the City of Northglenn Wastewater Treatment Plant (WWTP) located near residential areas?

The City built and put this facility into service in 1982 in Weld County. At that time, the area was almost exclusively agricultural and one primary reason for choosing the location was the distance from residential areas. 

The plant now has residential areas nearby because surrounding areas are part of a different municipality (City of Thornton) that allowed new residential development.

Why wasn’t I informed of the location of this plant when I moved here? Who allowed houses to be built here?

As the City of Thornton began planning to develop the surrounding area for residential buildout, a 1992 legal agreement between the two municipalities was established that had the following stipulations:

• Developers are obligated to disclose proximity to the plant.
• Thornton agreed to respond to complaints from residents.
• Thornton is limited to a maximum of one dwelling unit per acre or six dwelling units per acre within the identified Development Corridor per the agreement.

There is debate on whether these commitments have been upheld, but they are in place.

Why doesn’t Northglenn do anything to fix the smell?

First, as a wastewater treatment plant, we want to make it clear that it is impossible to eliminate all odors.

That said, Northglenn is committed to being a good neighbor. In the last three years the city has invested over $15 million in the wastewater system, and in 2021 has begun another $25 million of investments slated to take place over the new few years. The investments improve efficiency, storage methods, chemical treatment, transport and more – which all support minimizing odors. The current systems all meet or exceed state and federal regulations.

In addition, Northglenn works hard to adjust chemical treatments and use industry standards that help with odor mitigation. We are always open to trying new methods, but there are some limitations. Responsible use of public funds, state and federal laws/permitting, and completing due diligence to ensure efforts reduce (instead of exacerbate) the odors are all a part of the process. That process takes time, testing, and funding. We work hard to involve our industry partners to address this issue, and would welcome the opportunity to partner with the City of Thornton as well.

What exactly is that smell?

The WWTP processes all the wastewater that goes through the sewer system from the City of Northglenn. There are roughly 12,000 residences and 1000 businesses in the City, and this plant processes all the waste.

Please see our handout for specific steps we’ve taken in response to odor complaints.