How Rats Get Into Houses — the Entry Points I Check First

Most rats get into San Gabriel Valley houses from the top, not the bottom. Our local rat is the roof rat — a climber — and it reaches your roofline by way of the citrus tree, the ivy on the block wall, or the power-line drop, then works along the eaves until it finds an opening. It doesn't need much of one: a rat can squeeze through a gap the size of a quarter.

I've been crawling attics from Arcadia out along the foothills for over twelve years, and I walk the same inspection route on every rat call. Here it is, in the order I actually check it — top down, because that's how the rats do it.

The roofline comes first — our rats are climbers

Roof rats nest high, so I start where the house meets the sky. The classic entries up there: attic vents with torn or rusted screens (rats chew a small tear into a doorway), roof returns — that little pocket where the eave dies into the roof edge, which framers left open on a lot of the older housing stock around here — and lifted tile edges, where the wavy first course of an S-tile roof leaves half-moon channels running straight toward the attic. Before I look at any of that, though, I look at the trees. A mature ficus or citrus limb touching the roof is a freeway on-ramp, and ivy on a wall is a ladder rats will climb every night.

Then I drop to ground level

Ground-floor entries are less common here but easier to find. The garage door is the big one — the bottom corners flare with age, and if you can see daylight from inside a closed garage, a rat can see it too. After that I trace every line that penetrates the stucco: cable, gas, AC, irrigation. Installers drill generous holes and rarely close them up. Foundation vents with bent or missing screens come next, and last, the pet door — a flap that swings free at night is an open invitation, and I've pulled more than one rat out of a kitchen that came in exactly that way.

Why sealing first — and poison, period — backfires

Here's the mistake I get called out to fix: someone finds the gaps, seals them all in a weekend, and traps a family of rats inside the house. Sealed-in rats chew a new exit — often somewhere worse — or die in the wall voids, and you learn about that through the smell. Poison ends the same way, just slower: baited rats crawl into walls or attic insulation to die, and now you've got a carcass you can't reach and droppings you shouldn't disturb. If you're hearing activity overhead, my post on scratching noises in walls at night covers how to tell what you've got — and before you touch any droppings, read the hantavirus page, because dry sweeping is exactly the wrong move. One honest sorting note: noise during the day usually means squirrels, and that's a wildlife-removal job, not an exterminator job. Night noise is rats, and that one's mine.

Exclusion, done in the right order, is the fix that lasts

The order matters. Trap first, until the activity stops. Then seal every entry on the list — not just the obvious ones, because rats will find the one you skipped. Then verify, because I'd rather catch my own miss than have you catch it. That's the process behind my rodent control work, and it's backed by a one-year warranty. Repellents, ultrasonic plugs, and mothballs aren't on that list because they don't hold up in real attics. Before you call anyone — me included — here's the walk-around you can do yourself:

• At dusk, watch the power line and the back fence from the yard for a few minutes — rats commute the same route at the same time, and you'll spot them if they're there.
• Trim tree limbs and ivy back off the roofline so nothing touches the house.
• Walk the eaves with a flashlight: look for torn vent screens, open roof returns, and lifted tile edges.
• Close the garage door, kill the lights, and check for daylight at the bottom corners from inside.
• Follow every cable, gas, and AC line to where it enters the stucco and check for gaps or gnaw marks.
• Lock or cover the pet door at night.
• In the attic, look for droppings and dark, greasy rub marks — and leave any droppings alone until you've read up on cleanup precautions.

If the walk-around turns up a gap or two you can reach, go ahead and seal it — after you're confident nothing is living inside. If it turns up droppings, gnaw marks, or roofline gaps you can't get to, send me photos and I'll quote it free. There's no dispatcher and no call center — you're talking to the person who climbs the ladder. Scheduling is usually same week, often sooner.