The short version
Rodent control in California leans on trapping and exclusion because the state prohibits most uses of first- and second-generation anticoagulant baits. Roof rats are active year-round in coastal cities like Los Angeles and San Diego, house mice are everywhere, and deer mice in rural areas carry hantavirus; California reported four cases in 2025. Seal gaps over 1/4 inch and trap.
- California bars most uses of bromadiolone, brodifacoum, diphacinone, and similar anticoagulant baits.
- Roof rats travel 300 feet or more for food and stay active in California all year.
- California led the CDC's provisional 2025 hantavirus count with four cases.
- UC IPM says a rat fits under a 1/2-inch door gap; seal everything over 1/4 inch.
- Ask any provider which products they can legally use and how many trap checks are included.
This page is for homeowners, renters, landlords, and small-business owners anywhere in California, from Los Angeles and San Jose to Fresno and the foothills. If you have heard rats in the attic, found droppings in a garage, or been quoted a bait-only plan, it will help you ask the right questions.
What to look for
Then there is the law. Most first- and second-generation anticoagulants, including bromadiolone, brodifacoum, and diphacinone, cannot be applied in most areas, which pushes every job toward trapping and exclusion. Four rodents turn up in California's state data: roof rats, Norway rats, house mice and deer mice. The roof rat is the coastal headliner. It climbs, nests in palms, ivy, and attics, and according to UC IPM travels 300 feet or more for food, so the rat in your Los Angeles attic may be feeding three houses away. Winter lows around 43F mean it never stops. Norway rats hold the ground level, burrowing under slabs and foundations. House mice are in every city and pass through gaps of 1/4 inch. UC IPM adds that a rat gets under a door with a 1/2-inch gap, and a worn garage door seal can leave that much room. The deer mouse is the rural and foothill rodent, and it carries hantavirus. California's four provisional cases in 2025 were the most of any state.
- 1Running sounds across the ceiling at dusk, typical of roof rats using the attic as a highway.
- 2Droppings about half an inch long on the garage floor, in the attic, or along a fence top.
- 3Chewed oranges, avocados, or figs on the ground, hollowed from one side.
- 4Greasy smudges along a stucco wall, a palm trunk, or the top of a block fence.
- 5A burrow with fresh soil beside a foundation, planter, or trash enclosure.
- 6Droppings in a foothill cabin, shed, or RV that has been closed for a while.
Why it’s worth acting soon
- Roof rats breed through California's mild winter, so an attic colony keeps growing.
- Chewed wiring in an attic or a parked car is a repair bill on top of the pest bill.
- Deer mouse droppings in a rural garage become a hantavirus exposure when swept dry.
- The CDC lists hantavirus, leptospirosis, and salmonellosis among diseases rodents spread directly.
- Every month unsealed is another month of rats learning the route into your house.
Treatment options and typical costs
Exclusion
Quoted after inspection
A technician seals roofline gaps, vents, garage door edges, and utility penetrations with hardware cloth, flashing, and steel wool. UC IPM's standard is to close every hole larger than 1/4 inch. Under California's bait rules this is the backbone of a lasting plan, not an add-on.
- Time
- Set after the inspection
- Best for
- Every California home with rat or mouse activity
Trapping program
Quoted after inspection
Snap traps in the attic, along walls, and on exterior runways, checked and reset over several weeks. With anticoagulant baits largely prohibited, trapping is the main way California providers reduce a population, and it confirms which species you have and when activity stops.
- Time
- Several weeks
- Best for
- Roof rats in attics, mice indoors, homes with pets
Permitted bait in locked stations
Quoted after inspection
Where bait is still legal, providers may use bromethalin, cholecalciferol, or zinc phosphide products in tamper-resistant exterior stations. Ask which product they plan to use, why it is permitted at your address, and how often stations are serviced. Bait never replaces sealing the house.
- Time
- Ongoing where used
- Best for
- Heavy exterior pressure at commercial or dense urban sites
Prices are typical published ranges. Ask what’s included before you compare quotes.
Under the sink is the first place to check: the hole where the pipe passes through the cabinet back is often cut much bigger than the pipe.What California's rodenticide rules mean for your quote.
Which product, if any, will you use, and why is it allowed at my address? How many trap checks are included? What happens if I still hear rats after the last visit? A provider in Los Angeles or San Jose who answers those precisely knows the rules. One who says they will just put out bait may not. Most uses of first- and second-generation anticoagulant rodenticides are now banned in California. UC IPM lists the affected actives as bromadiolone, brodifacoum, difethialone, diphacinone, chlorophacinone, and warfarin, and notes that bromethalin, cholecalciferol, and zinc phosphide remain available. The practical effect is that a California rodent job is a trapping and sealing job. That changes what a fair quote looks like. Expect a list of entry points and materials, a trapping schedule with return visits over several weeks, and possibly a permitted bait product in locked exterior stations where pressure is heavy. Expect more labor hours than a bait-based plan in another state would need. It also changes what to ask.
Which rodents will you meet in California homes?
The Norway rat is the burrower, found at ground level. It digs under slabs and foundations and comes up through crawlspaces. The house mouse is in every city, using gaps of 1/4 inch, and it is the rodent you are most likely to meet in a Fresno garage or a San Jose pantry. The deer mouse is the rural and foothill rodent and the hantavirus carrier. California's four provisional 2025 cases are the reason any droppings in a closed cabin, barn, or shed should be treated with ventilation and bleach rather than a broom. Knowing which of the four you have decides whether the work is on the roofline, at the foundation, in the kitchen, or in the outbuilding. Four species appear in California's state data. The roof rat is the coastal climber, nesting in palms, ivy, and attics from San Diego to San Francisco and traveling 300 feet or more for food by UC IPM's account. Chewed citrus and avocados on the ground are its signature.
Fall is when rodents head indoors. Leaf piles against the foundation hide burrows and gaps, so clear them and walk the wall before the first cold snap.What does the first visit from a California rodent control company look like?
On a foothill property they look at outbuildings for deer mouse sign. Before they leave, ask for three things in writing: the entry points found with the sealing materials, the number of trap-check visits, and the name of any bait product they intend to use and its legal basis. In California, a quote without a sealing list is a quote for a problem that comes back. Because bait is limited, the first visit should be mostly inspection. On a coastal home the technician walks the roofline looking at tile ends, vents, and the joint where roof meets wall, plus every palm frond or vine that touches the house. At ground level they check the garage door against UC IPM's 1/2-inch rat rule, weep screeds, and utility penetrations. Inside, the attic is the main stop: droppings on insulation, rub marks on rafters, chewed duct or wiring. In the garage, the stored boxes and the water heater closet are where droppings tend to collect.
Hantavirus in California: where it is and how to clean up safely.
Open the doors and windows and leave for 30 minutes. Wearing gloves, wet the droppings with 1.5 cups of bleach in a gallon of water, wait five minutes, then wipe everything into a bag with paper towels. Never sweep or vacuum. For heavily contaminated outbuildings, hiring a provider with respirators and bagging is the safer choice. The CDC's long-run numbers, 890 cases since 1993 with 35 percent fatal, are the reason the rules are strict. They are not a reason to panic over a mouse in a Fresno kitchen, which is far more likely a house mouse. California reported four hantavirus cases in 2025 in the CDC's provisional count, the most of any state, and the usual exposure is the same: deer mouse droppings in a cabin, garage, or shed, disturbed in an enclosed space. Deer mice are mostly a rural and foothill animal, so the risk sits mainly outside dense city centers like Los Angeles and San Jose. The cleanup rule is the same everywhere.
Preventing rodents in California stucco and tile-roof homes.
Replace it and check the side seals. Pack steel wool around the air conditioning line set and any pipe or cable penetration through the stucco. Manage food and water. Pick up fallen citrus, avocados, and figs every few days, and keep pet food and chicken feed in metal bins. With only about 15 inches of rain a year, a dripping hose bib or pet bowl is the wettest spot on the block. In foothill homes, keep sheds free of stored food and bedding. Under California's bait rules, prevention is most of the plan. Start with the roofline, because that is how roof rats get in. Close open tile ends at the eaves with bird stop or hardware cloth, and replace screen on attic vents with 1/4-inch hardware cloth. Then the garage. UC IPM says a rat fits under a 1/2-inch gap, so a worn bottom seal is an open door.
What affects the price
- Roofline sealing, especially on tile roofs, which takes ladder time on every side.
- More trap-check visits, since California's bait limits mean labor replaces product.
- Attic insulation replacement after a season of roof rat nesting.
- Palms, ivy, and fruit trees that must be cut back before exclusion holds.
- Deer mouse cleanup in foothill and rural properties done under CDC rules.
- Neighborhood pressure, because roof rats forage 300 feet or more from the nest.
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What's your biggest concern about rodent control?
When to call for help
Call sooner for any droppings in a foothill cabin, barn, or shed, since deer mice there are the hantavirus carriers behind California's four 2025 cases. Ask for the list of entry points and the trap-check schedule before you agree to anything. Call a rodent control company in California when you hear roof rats overhead more than once, find chewed fruit under your trees, or see droppings in the garage. Because the state limits anticoagulant baits, the fix is labor, and a provider who inspects the roofline and seals it is worth more than one who drops a station.
What you can do yourself
California homeowners can handle a few house mice with snap traps and steel wool, and the state's bait rules make that the right instinct anyway. What you cannot easily do yourself is find the roofline entries roof rats use on a two-story stucco house, or seal a garage door so that no gap exceeds 1/4 inch, or keep up with a rat that forages 300 feet a night across three yards. A professional brings the ladder, the exclusion materials, and a trapping schedule with return visits, which under California law is the core of the job. They also know which of the remaining bait products, if any, are allowed at your address. In rural Fresno County or the Sierra foothills, add one more reason: deer mouse cleanup with respirators and ventilation. If the attic is still noisy after several weeks of trapping, there is an opening at the roofline nobody has found.
Where you live matters
Roof rats, Norway rats, house mice and deer mice all appear in the state data, from Los Angeles and San Diego to San Jose, San Francisco and Fresno. Median rainfall is only about 15 inches, so irrigated yards, fruit trees, and pet water become the draw, especially in the drier inland cities. Median winter lows around 43F keep rats active all year, and UC IPM advises checking for them periodically in every season. California's cities in our data cover three climate zones, coastal, arid, and temperate, but a few facts hold across them. And the anticoagulant restrictions mean every plan is built on sealing and trapping rather than bait. At a median home value near $720,000 across the cities, every chewed wire and soaked batt of insulation sits in an expensive house. Rural and foothill properties are where deer mice matter most, and California led the 2025 provisional hantavirus count with four cases.
Simple ways to keep rodents away
- Trim palms, ivy, and tree limbs so nothing touches or overhangs the roof.
- Pick up fallen citrus, avocados, and figs every few days during the fruiting season.
- Seal the garage door so no gap exceeds 1/4 inch; a rat fits under 1/2 inch.
- Cover attic and foundation vents with 1/4-inch hardware cloth instead of screen.
- Keep pet food, chicken feed, and bird seed in metal bins with lids.
- In foothill and rural homes, air out sheds and cabins for 30 minutes before cleaning after any closure.
In a multi-unit building, mice move between apartments through shared walls and pipe chases, so treating one unit rarely solves it. Ask for a building-wide plan.Did you know?
UC IPM's house mouse guidance is the companion to its rat notes, and both point to sealing and trapping as the first line under California's rodenticide restrictions.
Roof rats can produce three to five litters a year of up to eight young, and California's 43F median winter low does nothing to slow them.
Human plague in the United States averages seven cases a year, and California is one of the western states where the CDC maps it.
Questions people ask
Can pest control companies use rat poison in California?
Bromethalin, cholecalciferol, and zinc phosphide remain. The law pushes control toward trapping and exclusion, and a good provider will explain exactly what they can use at your California address. Only some of it. Under the state's restrictions, most uses of first- and second-generation anticoagulants are off the table, and UC IPM names bromadiolone, brodifacoum, difethialone, diphacinone, chlorophacinone, and warfarin among them.
Are rats a year-round problem in California?
UC IPM treats rats as active year-round in California, so periodic checks are the standing advice. With median winter lows around 43F across California cities, roof rats keep breeding in attics through December, and coastal cities like Los Angeles and San Diego see no real off season. Yes.
How bad is hantavirus in California?
The carrier is the deer mouse, mostly found in rural and foothill areas rather than city centers. Exposure comes from dried droppings in closed sheds, cabins, and garages, so ventilate and use bleach solution rather than a broom. California had the highest state count in the CDC's provisional 2025 hantavirus table, with four of 17 cases nationwide.
How far do roof rats travel from the nest?
That is why a rat in your San Jose attic may be feeding on a neighbor's fruit trees and why exclusion on your own roofline matters more than trapping the yard. Their nest and their food source are often on different properties. UC IPM says roof rats travel 300 feet or more for food.
How big a gap does a rat need to get in?
UC IPM puts it at 1/2 inch under a door, and it advises sealing every hole larger than 1/4 inch because mice use the smaller ones. On a California stucco home, common gaps are the garage door bottom, the roof-to-wall joint, and vents covered with screen instead of hardware cloth.
Is leptospirosis a risk from rats in California?
The CDC's weekly table shows two California leptospirosis cases in early 2026 through week 13, compared with three in the same period of 2025. Urban rats and dogs are the usual exposure routes, so keep pets from drinking standing water where rats are active. It is present but uncommon.
Why does rodent control cost more in California?
With a median home value around $720,000 across California's cities, the attic insulation and wiring at stake are costly too. Ask for the visit count and the sealing list before comparing totals. Labor replaces product. Without most anticoagulant baits, a provider has to seal the house and return to check traps, and every return visit is billed time.
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The facts in this article come from the public sources listed above. Every home is different, so ask the company you talk to about pricing and what’s included. Published by Rodent Exterminator · Updated October 11, 2026 · How we write these guides