Install a 12-inch-square piece of aluminum flashing or galvanized metal around conduit pipe to prevent rodents from climbing. Caulk gap around pipe if opening is larger than ¼ inch.
Due to their body shape, mice are capable of fitting through holes much smaller than appear likely. Mice may also enter the home through gaps in windows or ceilings, as well as through sewer lines. If drainage pipes are not properly sealed, mice may enter homes through sink or bathtub drains.
You can purchase mesh wire made to block the drain pipes from wildlife entering at hardware stores or if you mean on the outside of the pipe a little separation between the structure and the pipes would hamper their ability to climb on the outside...
Basically, stuffed steel-wool in entrance holes around cables, pipes and then spray in a bit of expanding foam insulation. They chew some foam insulation and stop right away when they hit the steel wool. Guaranteed to work.
Steel wool - Mice are known to be able to chew through almost anything, especially if they think food is on the other side. However, one thing they can't chew through is steel wool. Fill any holes in your home with this material - air vents, kitchen cupboards, etc.
Seal up gaps and holes
Fill small holes with steel wool. Put caulk around the steel wool to keep it in place or use spray foam. Use lath screen or metal, cement, hardware cloth, or metal sheeting to fix larger holes. Cut material to fit around pipes.
Rodents and Water Pipe Damage
The damage from rodents chewing through water pipes can be substantial and can occur either over time, or as one big "flood." When damage is slow, a small amount of water will continuously seep in spaces within the walls, causing buildup of toxic mold and rotting of wooden beams.
To discourage mice, remove all food sources by storing grains, pet food, and other dry goods in metal containers. Make sure mice won't find nesting material by storing all soft, fluffy material like fabric, rugs and blankets in heavy plastic or metal boxes.
Baking Soda and Salt Barrier. Sprinkle a mixture of baking soda and salt around your drain openings. This abrasive barrier can deter bugs from crawling up the drainpipes. Reapply the mixture periodically to maintain its effectiveness.
Rats and mice are nocturnal with most activity taking place between approximately one half hour after sunset to about one half hour before sunrise. Garbage is an excellent food source for rodents. Store garbage and rubbish in rodent-proof containers.
Mice will have difficulty climbing some surfaces that do not have the imperfections they need to get a decent footing. Smooth and slick materials made from plastic, metal, glazed wood, and glass typically don't provide the necessary grip for a mouse's claws to grasp which make them a challenge to climb.
Peppermint oil is said to deter rats from entering treated areas. In high concentrations, peppermint oil may exhibit some repellency.
Grapes, raisins, rhubarb and walnuts are poisonous to mice and lettuce can cause them to have diarrhoea. Wild mice find food by foraging and so a portion of daily food that is provided for pet mice should be scattered in a cage to encourage this foraging behaviour.
The best way to get rid of rats or mice is by using traps. If using spring loaded traps for rats, bait three of them in a row without setting them. Bait with dried fruit, peanut butter mixed with oats, or cheese.
Zinc phosphide is an acute toxicant that causes the death of a house mouse within several hours after a lethal dose is ingested. It appears to be the fastest way of getting rid of mice by reducing their population.
But Epsom salt isn't just good for humans! It can also be used to repel rodents due to its acrid smell. Sprinkling Epsom salt onto your trash can lid or around areas where rodents are known to burrow creates a protective boundary that can keep them away.
Plus, vinegar isn't always effective at keeping rodents away. While the smell may irritate some, others bypass it completely to reach food. To combat the mice problem in your home, you'll need to rely on proven pest control methods to eliminate pesky pests.
One of the best measures to stop rats from entering your drains is to add a protective guard over any openings on your external drains. This means rats cannot squees their way into the pipes as they are blocked.
That being said, exterior mouse holes should be sealed with steel wool and caulk immediately upon discovering them.