July 21, 2026
Our team has traced rat activity back to some surprisingly small problems. Seed had been collecting beneath a feeder. A tree branch was resting against the roof. At another property, the rats were using a gap behind a utility line that was difficult to see from the ground. Once rats begin showing up, we look at what they are returning for and how they are moving around the property. The answer is not always inside the home.
Around Marin County, our team deals with both roof rats and Norway rats. Most of the attic calls involve roof rats. They climb well and may reach the house from a tree, fence, or cable without leaving obvious signs near the foundation. Norway rats behave differently. We are more likely to find their activity near the ground, particularly around crawl spaces and places where the soil allows them to burrow. The signs inside a home do not always point toward the original source. Our team has followed attic activity back to fruit dropping in a neighboring yard and to bird seed collecting beside a fence. Rats may travel farther for food waste than most homeowners expect.
Activity can happen year-round in San Rafael, Novato, Mill Valley, and surrounding communities. Cooler weather may push more rats toward buildings, but an open entry point can be used in any season.
Bird seed is one of the first things our team checks outside. A feeder can look perfectly clean until you stand underneath it. Seed and hulls collect on the soil, along fence lines, or beneath nearby shrubs. Rats feed there after dark and may eventually start exploring the house. Fallen fruit creates the same type of routine. A rat that finds food beneath a citrus or fig tree has a reason to return every night.
Inside, the signs are sometimes tucked out of view. A torn bag of dog food in the garage or a few grains behind the stove may be all that is available. Cardboard packaging will not keep a rat out for long. Pet food should come in at night. Fruit should be picked up before it sits on the ground. If the garbage lid is warped or will not close, replace it rather than weighing it down and hoping for the best.
Check the quiet areas first: under the sink, behind the washing machine, around irrigation lines, and anywhere water tends to collect after rain. The leak does not have to be dramatic. One slow drip from a leaky pipe in a crawl space can go unnoticed for months, especially if no stain appears inside the house.
Even when an obvious food source is removed, rats may continue returning if water is available nearby. A damp planter, leaking hose connection, or overflowing gutter can provide enough moisture to keep them close. Repairing the leak will not remove rats that are already nesting inside, but it will make the property less useful to them.
An attic gives rats almost everything they want. It is dark, rarely disturbed, and filled with material they can tear apart. Once they begin moving through the insulation, they leave flattened trails between nesting and entry areas. Droppings tend to collect along those routes rather than being spread evenly across the attic.
Garages are different. Activity is often hidden behind objects that have not moved in a long time. Instead of reorganizing the entire room, pull stored items away from the walls and look behind them. Torn packaging, shredded paper, and dark pellet-shaped droppings are more useful clues than general clutter. Outside, pay close attention to the space under decks and behind thick growth. Ivy against the home gives roof rats both cover and a way up.
The scratching may be loudest in a bedroom wall, but the opening could be twenty feet away. Once a rat reaches an attic or wall cavity, it can move through the structure. That is why sealing the gap closest to the noise often fails. Northbay Rat and Rodent checks the building in the same way the rats use it. For roof rats, that means looking up: branches near the roof, loose vent screens, fascia damage, and gaps around the eaves. Ground-level inspections focus more on garage seals, crawl-space openings, and areas where pipes pass through walls.
Do not seal an active opening just because it is easy to reach. A rat trapped inside may chew into another room or die somewhere inaccessible. We also come across repairs made entirely with expanding foam. Rats can tear through it. Entry points need a material suited to the opening, which may include metal mesh, flashing, or concrete.
Walk around the yard at dusk and look at what touches the house. A branch resting near the roof can act like a bridge. Dense shrubs may conceal the base of the wall, making droppings and burrows difficult to see. A fence covered in ivy gives roof rats a protected route across the property.
The bird feeder does not always have to go. Move it away from the house and check how much seed reaches the ground. A tray can help, but only if it is emptied and the surrounding area is still cleaned. Grills are worth checking too. We have found rat activity beneath covers where grease and food residue had built up below the cooking area. Start close to the structure. That is where changes are most likely to affect whether rats make the jump from the yard into the home.
Tonight, remove the things rats can use immediately. Bring in the pet bowls, pick up fallen fruit, and make sure the garbage is actually closed. Tomorrow, look for access. Pay particular attention to openings that are partly hidden. A worn garage seal may be visible, while a gap behind a pipe or beneath loose roof material is easier to miss.
Traps alone may stop the noise for a few days. If the same route remains open, another rat can use it. Northbay Rat and Rodent approaches trapping and exclusion as connected work rather than treating them as separate problems. Some homes also need cleanup after the activity has stopped. This is usually considered when an attic or crawl space contains widespread droppings, damaged insulation, nesting debris, or a lingering odor.
Call for an inspection when the signs keep returning, when the entry point cannot be found, or when activity is happening inside an area that is difficult to reach safely.
No. The bigger concern is what lands on the ground. Watch the area beneath the feeder for a few days. If seed is collecting around a fence, shrub, or deck, rats may be feeding there without ever touching the feeder itself. Moving it and cleaning underneath it may be enough. When activity is already established, taking it down temporarily is usually the cleaner option.
We have found rats in spotless homes. Cleanliness helps remove spilled food and hiding places, but it cannot compensate for an open roof vent or an unprotected gap around a pipe. The inspection should focus on how the rats are living there, not on blaming the homeowner.
Not for long. Rats tend to adjust to radios, lights, and ultrasonic devices when the area still gives them food or shelter.
A closed, well-maintained compost bin is very different from an exposed pile of kitchen scraps. Keep produce from rotting on the ground and inspect the bottom of the bin. Gnawed vegetables, repeated tunnelling, or droppings nearby are reasons to take a closer look. One disturbed patch of soil is not enough to confirm rats.
Begin outside. Secure the garbage and remove anything edible that has been left overnight. Then listen. If scratching is still coming from the attic or walls, do not start closing holes at random. The rats may already be inside. Northbay Rat and Rodent can identify the active route, determine where traps should be placed, and plan the sealing work in the correct order.
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