What Attracts Rats and Mice to San Francisco Properties?

Keeping rats and mice out of a building starts with understanding what attracts them in the first place. Food, water, shelter, and openings into the structure all play a role in rodent activity.

In San Francisco, I often find that rodent problems aren't caused by one issue. It's usually a combination of accessible food, hidden travel routes, and openings that allow rodents to move between the outside and inside of a building.

One of the first things to look for is accessible food.

Trash containers without tight-fitting lids, spilled food around dumpsters, pet food left outdoors, and fallen fruit can all attract rodents.

At restaurants and other commercial properties, I pay particular attention to trash storage areas, grease buildup, food debris beneath equipment, and areas where waste collects.

Even small amounts of food left behind can encourage rodents to return.

Keeping these areas clean and storing food waste in secure containers can make a significant difference.

Removing food sources is important, but it won't keep rodents out if openings around the building remain accessible.

During inspections, I look for gaps beneath doors, openings around plumbing and electrical penetrations, damaged vents, and gaps where exterior siding meets the foundation, especially around corners where rodents may gain access to wall cavities.

Rooflines and eaves also deserve attention, particularly when dealing with roof rats.

Mice can squeeze through openings approximately 1/4 inch wide, while rats generally need about 1/2 inch, depending on their size.

I use rodent-resistant materials such as galvanized or stainless steel mesh, metal flashing, mortar, and appropriate sealants to close these openings.

The goal is to make repairs that hold up over time, not simply cover an opening with expanding foam that rodents can chew through.

• See how I approach rodent exclusion work

When rodent activity is already present, trapping becomes an important part of bringing the problem under control.

Rats and mice commonly travel along walls, behind equipment, and through areas that provide cover.

I position traps along these routes rather than placing them randomly throughout a building.

Choosing the correct trap, identifying active travel routes, and checking traps regularly are all important.

Traps should also be placed where children, pets, and other non-target animals cannot access them. Enclosed trap stations can provide additional protection when needed.

Sealing openings doesn't always mean the problem is over.

Rodents may still be inside the building, and other access points may remain undiscovered.

Continued trapping and monitoring help determine whether activity is decreasing and whether additional exclusion work is necessary.

I also look for fresh droppings, rub marks, gnawing damage, and disturbed materials that may indicate ongoing activity.

Effective rodent control involves more than catching rats and mice.

Removing food sources, identifying entry points, making durable repairs, and continuing to monitor activity all work together.

At OHH RATS!, I focus on practical rodent control for commercial properties throughout San Francisco, including restaurants, retail spaces, and other businesses.

Every building is different, and understanding how rodents are using the property is the first step toward getting the problem under control.

• Commercial rodent control in San Francisco

• CDC — How to Trap Up to Remove Rodents
• CDC — How to Seal Up to Prevent Rodents