Rodents can damage property, carry diseases, and contaminate food, affecting you and those you care about. You and your neighbors can decrease rodent activity by removing what they want: food, water, and shelter.
If you have rodents on your property follow the information provided here and consider getting a professional assessment to confirm and address the rodent activity.
Definitions
Rodents
Small mammals that gnaw with sharp front teeth. This page focuses on rats and mice.
Other wild rodents commonly found in the Denver-Metro area including, but not limited to:
- Squirrels
- Porcupines
- Prairie Dogs
- Hamsters
Rats
Rats grow up to 18 inches long and typically have the same color all over their bodies.
Rat teeth grow 2-4 inches a year and can chew through plastic, frozen ground and concrete.
Am I a mouse or a rat?
These are both rats. You can tell by the large body size and consistent fur color.
Mice
Mice are small, ranging from two to five inches in length (not including the tail). They typically have slender bodies with brown or gray fur on their backs and heads, and lighter belly fur. They have pointed snouts and large, rounded ears.
Am I a mouse or a rat?
These are both mice. You can tell by the rounded ears and light fur color on the belly.
Abatement
Rodent abatement is the process of controlling and reducing rodent populations to protect public health, property, and the environment. It involves identifying signs of rodent activity, removing food and water sources, sealing entry points, and using traps or other control methods to eliminate infestations. Abatement efforts may also include sanitation improvements and regular monitoring to prevent rodents from returning. These measures are important because rodents can spread diseases, contaminate food, and cause structural damage through gnawing and nesting.
Denver is a vibrant and thriving city with almost 3 million people living in the city and surrounding metropolitan area. Rodents have adapted to live in areas where humans are the most active, taking advantage of our food, water, and shelter.
- Where in Denver do rodents live?
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Anywhere they can get shelter, food, and water in the same location. Rats have evolved to depend on humans. Cities with lots of humans will also have lots of rats. In Denver, underground spaces or deactivated tunnels are home to many different pests, including rodents.
- What kind of rats are in Colorado?
- Wood Rats or “Pack Rats” - will hoard materials in their den, especially shiny objects
- Norway Rats - the tail is shorter than the body
- Roof Rats - the tail is longer than the body
- How does DDPHE inspects for rodents?
DDPHE inspects public properties and right-of-way spaces (such as alleyways) for rodents. Rodent activity is confirmed if any of the following observations are made:
- Live rodents
- Dead rodents
- Burrows (open and active mean there is activity)
- Rodent droppings
- Gnaw marks from teeth (often on trash or debris left in the area)
- Rodent trails, tracks, or rub marks
- "Harborage" or "nesting" conditions such as excessive garbage or clutter that give rats a place to hide
- What about properties near parks, open space, water sources, and green space?
Rodents have lots of competition and danger from predators when living in the wild. Rats have evolved to live in urban areas near sources where they can get shelter, food, and water at the same time.
Denver Parks and Recreation monitors all public green spaces and address rodents where possible without disturbing wildlife.
Did You Know?
- Rats can base their diet completely on unprocessed nutrients in biological waste. Denver is one of the most pet-friendly cities in the U.S. with dogs being the most popular. City code requires property owners to clean any biological waste from the property and pet owners to pick up any waste created by their pet.
- Rats can reproduce faster than we can kill them. Female rats can have between 8 and 12 babies per litter and can have up to 20 litters per year. Options for abatement should start with slowing reproduction by harassing (disturbing) nesting grounds.
- Cats will not control rodent populations. Domestic cats prefer safe and easy meals. Felines will often eat native wildlife like birds and reptiles before they hunt for rodents.
- Poison does work on city rats, if they eat it. However, rats will eat trash and feces over eating bait.
- "My neighborhood has rats, but I don't" is a myth. if you observe rat activity in your neighborhood, work together with neighbors to keep local rodents under control.
Rodents spread disease to humans through direct contact such as handling, bites that break the skin, or touching rodent urine, feces, and saliva. Diseases can also be spread indirectly from insects or other pests (mostly ticks and fleas) biting rodents then biting humans or domestic Animals. Rodents living in urban areas have also been linked to an increase in allergies and asthma symptoms.
Hantavirus
Nationwide, a total of 864 hantavirus cases were reported between 1993 and 2022. The five states with the most cases are New Mexico, Colorado, California, Arizona and Washington, according to the Centers for Disease Control and Prevention.
Early symptoms can include fatigue, fever and muscle aches. About half of patients experience headaches, dizziness, chills and abdominal problems. About four to 10 days after the initial phase of the virus, symptoms can include coughing and shortness of breath and tightness in the chest as the lungs fill with fluid.
Outdoors
Look for any of the following:
- Live rodents (most active at night)
- Dead rodents
- Burrows (fist-sized holes in the ground, loose dirt, or piles of brush)
Indoors
Check if your home or business has any holes in the siding, cracks in the foundation, or gaps around entry points (such as windows or doors). Even if the space is small, rodents are powerful chewers and can gnaw at the opening until it is big enough to squeeze through. Mice can fit through gaps and holes the size of a dime. Rats can fit through openings the size of a quarter.
Once inside your home or business, rodents will look for a secluded, warm location with plenty of cover to build their nests. Some of the areas to check if you think you have a rodent problem include:
- Attics and crawl spaces
- Garages, especially corners near entrances
- Under and behind appliances (such as a dryer or refrigerator)
- In cabinets and under sinks
How to Prevent Rodents
Prevent rats and mice from living on your property:
- Keep your property clean inside and out by frequently picking up trash and yard materials.
- Plug any gaps or holes in buildings (even if these are only used for storage, such as a shed).
- Bring trash, recycle, and compost bins in at night whether they are empty or full. These should not be left in alleyways or on the street as rats will easily chew through to eat whatever in inside. Bins should be moved into a garage or secured behind fencing in a yard or patio to deter rodents.
- Rats love living in dense bushes and other shrubs that are low to the ground. Removing infested bushes from your property can greatly improve abatement success!
- If you are on the street or in a park, always put your trash in the can.
- Do not feed birds or other wildlife around your property. When you feed stray cats, you’re also feeding rats. If you do feed birds, place appropriate equipment and food off of the ground and away from building entry points (such as doors and windows).
Rodent Control and Abatement
Follow the the steps below to control and abate rodent activity:
- Inspect for signs of rat activity.
- Signs include burrows, rodent droppings, gnaw marks, and dead rodents
- Rats leave trails with body fluids (urine, feces, or grease marks) to help other rats find food water, and shelter. This can be managed with regular cleaning of floors, ceilings, and walls.
- Remove food sources and nesting materials.
- Common nesting materials include sticks or branch bundles, piles of rocks, piles of dead material (such as grass or hay), piles of loose dirt (such as a garden bed or a garden box), and hedges (used for protection from weather and predators).
- Seal any gaps, cracks, or holes that act as entryways. Take a walk around your property and look for any gaps between the walls, siding, under doors, or vents (like the dryer vent).
*Have a dumpster? Ensure all dumpsters are closed, plugged, and secured in such a way as to block rodent entry. Dumpster plugs fit into the sides of the dumpster near the bottom and can be filled with a standard plug or a DIY dumpster plug.
- Bait, trap, and kill the rodents.
- Search the web to find professional options or create DIY rodent traps to save money and begin abatement quickly.
*It is strongly advised NOT to use rodent poisons in your garden or home. You should always consult with a pest professional before placing down toxins, especially if you have pets or small children.
- Maintenance
- Burrow harassment: collapsing or filling burrows and holes with dirt on a regular basis.
A common method is “flushing rats” by putting a water hose directly into the burrow and letting it run/flood for several minutes. Rodents will disperse from other exits and are discouraged from returning when the wet dirt collapses.
**CAUTION: never pour bleach or poison directly in burrows. This can impact public services like drinking water.
- Request repairs or replacements for city garbage cans by calling 311.