How to Get Rid of Rats Permanently: Trap, Then Seal, in That Order
Rats come back because something let them in and something fed them. Permanent is not a better poison; it is sealing the house and changing the yard. Here is the whole sequence, in order.
The way to get rid of rats permanently is exclusion: find every opening a quarter inch or larger, trap the rats already inside, then seal the openings with materials rats cannot chew and remove the food and cover that drew them. In the San Gabriel Valley the rat is almost always the roof rat, a climber that enters at the roofline through vents, roof returns and gaps along utility lines, so the inspection starts up high. Trap before you seal, with a dozen or more snap traps on the runways and ledges roof rats use, because a rat sealed in dies in a wall. Then seal with hardware cloth, sheet metal and mortar, cut back limbs within six feet of the roof and the ivy on the fence, and lock down pet food, fallen citrus and trash. Poison is not the permanent fix, and since January 1, 2025, most anticoagulant rat baits are prohibited for residential use in California. Ultrasonic devices and repellents have no lasting effect.
Local help: Hearing them after dark? Text a photo of the droppings or the gap to (626) 409-1584. We trap, seal with a one-year warranty on the exclusion work, and clean up. Quotes from photos are free.
On this page
- Why permanent means sealing, not killing
- Step 1: find the entry points, roofline first
- Step 2: trap before you seal
- Step 3: seal with materials rats cannot chew
- Step 4: take away the food, water and cover
- Step 5: clean up without stirring up dust
- Is rat poison legal in California? What the 2025 law says
- What does not get rid of rats
- How long does it take to get rid of rats?
- What a rat exterminator actually does
- Sources
- Quick answers
Why permanent means sealing, not killing
Every rat in your attic got there through an opening and stayed because there was food and cover. Kill it and the opening is still there; the next rat on the fence line finds it in a week. That is why UC IPM calls exclusion the most successful and longest-lasting strategy for rat control around structures, and why it describes rodent management as a longer-term effort that often has to extend beyond your own yard. Permanent is a construction job with a trapping job in front of it.
| Trait | Roof rat (the San Gabriel Valley rat) | Norway rat |
|---|---|---|
| Build | Sleek, 5 to 10 ounces, tail longer than head and body, ears reach the eyes when folded forward | Stocky, 7 to 18 ounces, tail shorter than head and body |
| Where it lives | Above ground: trees, ivy, dense shrubs; indoors in attics, wall voids, cabinets | Burrows along foundations, under trash and woodpiles; indoors on ground floors and crawlspaces |
| How it gets in | Climbs: roof vents, roof returns, gaps at utility lines, limbs and vines that touch the roof | Low: foundation gaps, doors, broken drains |
| Where to set traps | Up: ledges, beams, pipes, top plates, along the attic joists | Down: perpendicular to walls, behind objects, in dark corners |
Step 1: find the entry points, roofline first
Start on a ladder. Our rats are climbers, and the roofline is where they get in: attic vents with torn or rusted screens, the roof return where an eave dies into the roof edge, the gap where the electrical service or cable enters, uncapped vent pipes over two inches across, a tile roof’s open ends. Then drop to ground level: foundation vents, the garage door’s bottom corners, the gap under any door over half an inch, openings around pipes and wires, the dryer vent, the crawlspace access. Look for rub marks (greasy smudges where fur drags along a surface), gnaw marks and droppings; they mark the runways. The full tour, with what each point looks like from a ladder, is in how rats get into houses.
Step 2: trap before you seal
Trap before you seal, or you seal rats in. UC IPM rates snap traps as the most effective and most economical way to trap rats, and placement matters more than the trap style.
- Quantity. Traps 10 to 20 feet apart along runways; a dozen or more in a heavily infested home.
- Placement for roof rats. Up where they travel: on ledges, pipes, beams, the top of the wall framing in the attic, along joists. Tie or screw traps to beams so a caught rat does not drag the trap off.
- Placement for Norway rats and ground runs. Perpendicular to the wall with the trigger end nearly touching it; in pairs if parallel.
- Bait. A pea-sized smear of peanut butter, or a piece of dried fruit, nut or bacon tied to the trigger with thread so the rat has to pull.
- Pre-bait. Rats avoid new objects for days or weeks. Leave traps baited and unset until the bait is taken, then set them all. If every trap is cleaned out, double the number.
- Protect pets and kids. Set traps inside boxes or stations, or in the attic and voids where only rats go.
- Skip glue boards and live traps. UC IPM does not recommend either for homeowners; glue boards must never be used outdoors because wildlife gets stuck, and relocating a rat is not recommended.
Step 3: seal with materials rats cannot chew
Seal every opening larger than a quarter inch. Rats chew through plastic, foam, wood and caulk, so those are fillers, not barriers. Use what UC IPM lists: steel wool or copper mesh packed into gaps and sealed over, galvanized hardware cloth with half-inch mesh (never chicken wire, which rats walk through) over vents, sheet-metal flashing at roof returns and corners, mortar or concrete at the foundation. Fit door sweeps and weatherstripping so no door has a half-inch gap, including the astragal between double doors. Put a spark-arrester cap on the chimney and screens on vent pipes over two inches. Then cut the bridges: remove limbs within six feet of the roof, pull ivy and star jasmine off fences and walls, and thin shrubs so they stand two feet apart and off the house. Materials and gap sizes, item by item, are in our rat-proofing checklist.
Step 4: take away the food, water and cover
The San Gabriel Valley feeds rats well: backyard citrus and avocado, fallen fruit, pet food left out, bird feeders, open compost, snail bait. Pick up fallen fruit and nuts, feed pets only what they finish, store pet food and birdseed in metal cans with lids, keep compost in a rigid container with a tight lid, and put a tight cover on every trash can. It will not remove a rat that is already inside, but it is the difference between an exclusion that holds and a yard that keeps recruiting the next one. More on the citrus problem in roof rats and citrus trees.
Step 5: clean up without stirring up dust
Rats carry typhus, leptospirosis, salmonella and rat bite fever, and their droppings and urine can harbor hantavirus. Never sweep or vacuum droppings dry. Wear gloves, wet the area with disinfectant first, wipe it up, bag it and wash your hands afterward. Dead rats go into a sealed bag with gloves on. Our hantavirus page has the full cleanup procedure and when to leave it to us.
Is rat poison legal in California? What the 2025 law says
Poison was never the permanent fix: it leaves dead rats in walls, it does not close the hole, and the owls, hawks, coyotes, dogs and cats that eat a poisoned rat get a dose too. California has now taken most of it off the table. Second-generation anticoagulants (brodifacoum, bromadiolone, difenacoum, difethialone) have been restricted since 2021, and under AB 2552 most uses of the first-generation anticoagulants (diphacinone, chlorophacinone, warfarin) were prohibited starting January 1, 2025, including residential use. The Department of Pesticide Regulation’s guidance says existing stocks had to come off retail shelves by that date; take any you have to a household hazardous waste site. What remains for homes are non-anticoagulant baits such as bromethalin and cholecalciferol, used in bait stations (tamper-resistant wherever children, pets or wildlife could reach them) within 50 feet of the structure, and they still leave rats to die wherever they happen to be. We trap.
What does not get rid of rats
- Ultrasonic repellers. Rats quickly become accustomed to repeated sounds; UC IPM calls the devices ineffective for rats in homes and gardens.
- Peppermint oil, mothballs, dryer sheets. No repellent has solved a rat problem for more than a very short time, and none are registered as effective in California.
- A cat or an owl box. Predators cannot bring an established population down, and cat food left out feeds rats.
- Sealing first. Traps rats inside; they die in the walls or chew out.
- Relocating a trapped rat. Not recommended; it is also someone else’s problem now.
- Poison in the attic. See above; and it is now largely illegal for homes.
How long does it take to get rid of rats?
- Day 1. Inspection from the roofline down; traps placed and pre-baited.
- Days 3 to 14. Traps set and checked; catches fall to zero.
- Days 10 to 16. Every opening sealed in one pass, bridges cut, food locked down.
- Weeks 3 to 6. Monitoring: fresh droppings or new gnawing mean a missed opening, which the warranty covers.
- Then. Attic cleanup if droppings and nesting need removing, and a fall check of the roofline before the next cold snap pushes rats indoors.
What a rat exterminator actually does
A rat exterminator who only sets bait is selling you next year’s rat. What you should be paying for is the inspection that finds every opening, the trapping that clears the house, the sealing done with the right materials in the right order, the cleanup, and a written warranty on the exclusion so a missed gap is their problem, not yours. That is our rodent control service: trap, seal with a one-year warranty, sanitize. Price depends on the house and is quoted in writing after a look. A photo of the droppings or the gap to (626) 409-1584 is the fastest way to start.
Sources
Common Questions
Quick Answers.
How do you get rid of rats permanently?
Exclusion. Find every gap a quarter inch or larger, especially at the roofline, trap out the rats already inside, then seal the gaps with hardware cloth, sheet metal and mortar and remove the food and cover outside. UC IPM calls exclusion the most successful and longest-lasting strategy for rat control around structures. Poison and repellents are temporary by nature.
What is the best way to get rid of rats in a house?
Snap traps, set correctly and in quantity, followed by sealing. UC IPM rates snap traps as the most effective and most economical way to trap rats. Place them along walls and, for roof rats, up on ledges, beams and pipes; use a dozen or more in a heavily infested home; bait with a pea-sized smear of peanut butter or a tied-on piece of dried fruit or bacon.
Should I seal the holes before or after trapping?
Trap first, then seal. Rats sealed inside die in walls and ceilings, and a rat that cannot get out will chew a new hole. Set traps for a week or two until the catches stop, then close everything in one pass.
How long does it take to get rid of rats?
Usually two to four weeks for a typical house: a week or two of trapping, one or two days of sealing, then a monitoring period to confirm nothing is getting back in. Rats are wary of new objects, so traps can sit untouched for several days before the catches start.
Will rats go away on their own?
No. A house with an entry, water and food is a good place to live, and roof rats breed several times a year. Numbers only go one direction until something changes.
Is rat poison legal in California?
For most residential use, no longer. California restricted the second-generation anticoagulants in 2021, and under AB 2552 most uses of the first-generation anticoagulants (diphacinone, chlorophacinone, warfarin) were prohibited as of January 1, 2025. What remains for homeowners is a short list of non-anticoagulant baits that must sit in tamper-resistant stations. Poison also leaves dead rats in walls and poisons the owls and pets that eat them, which is why we trap.
Does peppermint oil or an ultrasonic repeller get rid of rats?
No. UC IPM is direct: rats quickly become accustomed to repeated sounds, so ultrasonic devices are ineffective, and no repellent has been found to solve a rat problem for more than a very short time. There are no truly effective rat repellents registered for use in California.
How many rat traps do I need?
More than you think. UC IPM suggests placing traps 10 to 20 feet apart and says a dozen or more may be needed for a heavily infested home. Leave them baited but unset for a few nights until the bait is being taken, then set them all at once.
What attracts rats to a house in Southern California?
Citrus and avocado trees, fallen fruit, pet food left out, bird feeders, open compost, ivy and dense shrubs against fences, and a roofline with unscreened vents or gaps where utility lines enter. Roof rats also travel along fence tops and tree limbs that touch the roof.
Is it rats or mice, and does it change the plan?
Roof rats leave pointed droppings about half an inch long and need a half-inch gap; mice leave rice-sized droppings and fit through a quarter inch. The plan is the same (trap, then seal), but mouse-proofing has to close smaller gaps, and rat snap traps often will not trigger for a mouse, so you set mouse traps as well.
How much does a rat exterminator cost?
It depends on the house: how many entry points need sealing, how high the roofline work is, and whether the attic needs cleanup after the activity stops. Exclusion is priced per home, not from a menu, and our exclusion work carries a one-year warranty. The quote is free and in writing after we look.
What do rats hate?
Nothing that lasts. Rats show a brief aversion to new smells and sounds and then ignore them; UC IPM found no repellent that solves a rat problem for more than a very short time, and no effective rat repellent is registered in California. What rats cannot get past is quarter-inch hardware cloth and a sealed roofline.
Can an exterminator get rid of rats permanently?
Yes, if the job is exclusion and not just bait. Look for an inspection that starts at the roofline, trapping before sealing, materials rats cannot chew, and a written warranty on the sealing work; ours is one year. A company that only sets bait stations is managing rats, not ending them.
Keep Reading
About the Author
Joshua A. Westad is the owner and licensed operator of ExterMetro Termite and Pest Control in Arcadia, CA. He holds California SPCB Company Registration #8828 (Branch 2 & 3), is a licensed WDO inspector, and has worked San Gabriel Valley homes and businesses for over twelve years — hands-on in the field on every kind of job the valley throws at him.
Think you just found termite evidence?
Bag a few wings or pellets, snap a photo, and text it to (626) 409-1584 — quotes from photos are free, and your job stays under licensed ExterMetro oversight from inspection through follow-up.