Mosquito Control

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Denver’s Mosquito Management Program uses an approach designed to reduce public health concerns, and provide information and education to residents and business to help them keep mosquito populations at a safe level.

We recognize mosquitoes are a nuisance and can be especially active in neighborhoods that are near waterways and natural areas. The program focuses on preventing mosquitoes through these activities:

Survey larval mosquito populations in around 50 sites city-wide, and apply larvicide (kill mosquito larvae) when conditions warrant it
Trap, count, and test adult mosquitoes to monitor for West Nile Virus
Investigate and respond to citizen complaints
Partner with neighborhood organizations and other land owners to assist them in controlling mosquitoes. Our partners include:

Additional Information

You can protect yourself and your neighbors from mosquito bites in two ways – through prevention and elimination of stagnant water where mosquitoes breed:

Prevention Tips

Limit activity outdoors at dusk and dawn
Wear protective clothing like pants and long sleeves when outdoors
Wear mosquito repellant containing lemon eucalyptus oil, DEET, picaridian, or IR3535
For more information on insect repellants, visit EPA’s website.

Eliminate Mosquito Breeding Sites

Frequently remove standing water from containers, tires, birdbaths, gutters and buckets around your home
Do not overwater your yard, as it can create standing water in gutters and storm sewers
Properly maintain fountains and swimming pools to ensure circulation, or drain and cover if not in use

Mosquito-Proof Your Home

Install screens on windows and doors
Make sure roof gutters are not clogged and holding water
Incorporate xeriscape (non-watered landscaping) to further help reduce the number of mosquitoes in your neighborhood

Understanding mosquitoes is the first step in preventing them. We offer a variety of educational materials and information focused on neighborhood-level prevention of mosquitoes. Please call 3-1-1 or email EQcomments@denvergov.org for additional information.

Denver does not spray for or contract for the spraying of adult mosquitoes. Controlling larvae, which are concentrated in discrete areas of standing water is considerably more effective than targeting adults that are more dispersed. Spraying provides only a short-term solution that will require multiple applications, and does nothing to eliminate larvae present in standing water. Spraying also produces environmental and public health concerns. Denver Public Health & Environment will only spray for mosquitoes if there is a serious outbreak of West Nile Virus.

Dump containers holding water (wheelbarrows, buckets);
Maintain fountains and swimming pools, drain water or assure it is moving and/or being chlorinated (or equivalent);
Assure you don’t have blocked roof gutters holding water and producing mosquito habitat;
Do not allow landscape irrigation to collect and pool in sidewalks and gutters;
Make wise landscape decisions (create spaces that make it easier to avoid overspray into gutters and sidewalks);
Fix leaking irrigation systems; and
If you do have pooling in street gutters, disturb it regularly (with brooms, vehicles, etc).

Denver traps and collects adult mosquitoes at five sites across the city to determine if West Nile Virus (WNV) is present in local mosquito populations. The samples are sent for testing to the Colorado Department of Public Health and Environment.

Testing of adult mosquitoes over the past several years documented the occurrence of WNV in Denver’s adult mosquito populations in 2007, 2011 and 2014. Testing of Denver’s adult mosquitoes did not occur in 2012 and 2013.

Data for neighboring counties indicates that WNV was found in adult mosquitoes throughout the region in 2014, particularly rural areas north of Denver along the front range.

The number of Culex species (those most likely to carry WNV) collected in Denver traps is comparable to, or lower than, what was found in nearby counties (Adams, Arapahoe, Boulder, Jefferson).

What does this mean for you?

While the risk of exposure to WNV is low, you should still protect yourself. Mosquitoes generally remain active throughout the summer until September or until colder nights set in (e.g. 40’s). See “Protect Yourself from Mosquito Bites” for more information.

Zika Virus is most commonly spread to people through mosquito bites. The mosquito that spreads Zika lives mostly in warm (tropical and subtropical) regions of the world and is not found in Colorado. The risk of Zika coming to Colorado and spreading through mosquito bites is very low.

DDPHE and Denver Public Health are working closely to monitor the spread of the disease, identify risks and plan for the possibility of a case in the metro area.

View a Zika Virus fact sheet in English and Spanish.