What You Can Do

When it comes to rodent control around your own house, there are a number of things you can do to make your house "less attractive" to rats. Some actions are as simple as bringing in pet food at night, or harvesting fruit in your yard, to exclusion techniques you can use around the house.

Habitat Management

Roof rat survival and prosperity are dependent upon the existence of three basic environmental conditions:

• Abundance of food
• Available source of water
• Access to suitable harborage

Good environmental management practices supplemented by the wise use of rodenticides are the most effective approaches to roof rat control. Sanitation and good housekeeping are the first steps in a successful rat control program. The homeowner can help control rat populations by doing the following:

• Harvest oranges, avocadoes, peaches, apricots, plums, walnuts and tangerines as soon as they ripen. Pick up all fallen fruit.
• Never leave uneaten pet food outside overnight.
• Keep pet food in sealed metal containers if stored in the garage or other outbuildings.
• Keep palm trees and other plants well trimmed. Algerian ivy, creeping fig, oleander, bougainvillea, and other thickly matted plants should be periodically thinned and trimmed well away from roofs, walls, fences, utility poles, and trees. For a complete list of plants that rats nest in, click here.

Ivy	Oleander
Bouganvillea

Store wood and lumber piles on racks at least 18 inches above the ground and 12 inches away from walls (click here to see video). Storage boxes housed in utility sheds should be stacked close together and in an orderly fashion. Clean up debris piles. Repair leaky faucets and eliminate any other unnecessary standing water.

When renovating the yard and/or planning new landscaping, undesirable landscape vegetation should be eliminated from the plans and replaced by vegetation types that do not afford harborage to rats. A list of alternative landscaping (e.g. ground covers) is available on this website.

Building Maintenance

Roof rats can enter a home through small exterior openings of less than one inch in diameter. For common roof rat entry locations, click here. Important steps a homeowner can take to exclude rats are inspecting and repairing:

• Basement windows and ventilation ports
• Attic vents and louvers
• Gaps between roof and chimney
• Vent pipes and shafts
• Tile roofs along the eaves

All access openings should be screened with 1/4 inch galvanized hardware cloth and inspected at least once a year for the condition of the repair. Gaps around pipes and electrical conduit should be sealed, and cracks around doors and windows should be weatherproofed. (To see a video of a rat entry being sealed, click here). Tree limbs should be kept well away from the eaves, roof, and exterior walls of the house.

Vent Opening Blocked with Steel Wool	Opening screen with Galvanized Hardware Cloth
Opening screen with Galvanized Hardware Cloth

Rodent Proofing Your Residence

Rodents in the walls and attic of your home are unnerving. Your house, garage, and sheds are favorite nesting places for rodents. These unwanted guests will set up housekeeping, rear their young, chew on electrical wires, feed on pet food, and anything else within reach.

Another reason to discourage rodents from sharing your residence is the possible chance of disease, not to mention the panic some people experience upon discovery of rodents indoors.

*** Make sure you do not put out any baits or poisons if rodents are in your structure. Rats can die inside the walls or in your attic and can cause an odor problem and a fly problem. ***

Rodent proofing is an easy "Do-It-Yourself" project. The average home can be rodent proofed in one to two hours by a homeowner with average skills using common tools. All supplies needed are inexpensive and available through your local home improvement center.

Suggested Tools Needed:

• Hammer
• Staple gun
• Pliers
• Screwdriver
• Putty knife
• Ladder
• Tin snips
• Portable drill
• Measuring tape

Materials Needed:

• ¼" Hardware cloth (sold by the yard)
• House vent insert
• Crawl space vent
• Stucco or plaster patch
• Bronze or steel wool
• Door threshold
• Door weather stripping
• Flashing (sheet metal)
• Wood snap traps
• Metal trash can (for pet food)
• Sheet metal screws
• Expanding foam filler w/steel wool

Click here to view problems and solutions for examples of how to exclude rodents from your structure.

Trapping

Rat traps may be use in the yard and inside buildings with good results. Wood snap traps are inexpensive, give positive results, and eliminate the possibility of a poisoned rat dying in an inaccessible area. Rat carcasses within a structure can cause serious odor and fly problems.

Several traps may be set at once for maximum effectiveness. The following baits are most attractive to rats:

For best results, try several different baits to see which is accepted most frequently by rodents. If fresh food is abundant for the rodents, use a bait somewhat different than what is available to them.

These baits should be kept in fresh condition for best results and should be securely fastened to the trigger.

Traps should be placed along known rat runways such as fence tops and walls, where rat activity is evident. Securely anchor traps to an immovable object to keep any trapped animals at the placement site.

• Adjusting Snap Traps
  
  Before baiting the trap, check for sensitivity of the trigger. The trap should be sensitive enough to snap closed when the rodent feeds or otherwise touches the baited trigger, but not so sensitive as to snap if roaches or other insects come in contact with it. Trigger sensitivity can be checked by lightly touching the trigger of a set trap with a screwdriver. If the trap does not snap, the metal trigger tab can be bent outward to make it more sensitive. If the trap is too sensitive, the trigger tap can be bent inward.

• Setting a Snap Trap
  
  To set a snap trap, apply recommended bait to the trigger. Pull back the bail with your thumbs. Hold the bail in place with one thumb while attaching the bar to the trigger tab. Carefully place the trap as recommended in the diagrams. Better results are usually obtained if two traps are set side-by-side.

• Prebaiting Traps
  
  It is also a good idea to prebait, which is to use a baited but unset trap, so that the rodent can become familiar with and start feeding on the baited trap. This requires only two or three days, after which the traps can be set.
  
  
  • Bait Options
    • Peanut butter on steel wool
    • Dried meats
    • Anything else the rodent would have to tug to remove from the trap
      
      
• Maintaining Traps
  
  The working parts of the trap should be oiled occasionally using mineral oil, never petroleum based oils. Petroleum oils may act as a repellent to rodents. Never store traps near insecticides or other chemicals, or handle domestic animals or pets before setting out traps. These can also cause traps to take on a repellent odor.
  

Proper Disposal of a Rat Carcass

Using a plastic bag, place your hand in the bag like a glove, pick up the carcass with the bag, invert the bag or turn bag inside out, tie a knot at the end of the bag, and dispose of rat in a trash container with a secure lid.

For the District's specific guidelines on how to avoid or reduce mosquitoes, rats, red imported fire ants, and flies please refer to recommendations in the Vector Reduction Manual: Procedures and Guidelines.