15.7 million
occupied U.S. homes reported signs of mice or rats indoors in the prior 12 months.
That figure comes from the 2023 American Housing Survey, which covered 133.2 million occupied housing units nationwide.
Updated October 9, 2026
Rodent statistics and facts for California homeowners.
Reliable numbers can make a home concern easier to understand. This reference brings together national housing data and California rodent guidance from public sources, with each figure linked to its original publication.
U.S. housing data
Signs of rodents are a common housing concern.
7.2 million
occupied U.S. homes had open cracks or holes inside.
The survey reports this housing condition separately from rodent sightings. It is useful context, not proof that a particular opening has caused an infestation.
Rats around California homes
Species and behavior shape where to look.
2
introduced rat species are common in California cities: roof rats and Norway rats.
UC Integrated Pest Management notes that both species occur in many California urban areas, but their habits around a property differ.
Source: UC Statewide Integrated Pest Management, Rats, updated June 2025
300+ feet
is a typical roof-rat travel distance for food.
Roof rats can nest in landscaping at one residence and feed in fruit trees at another, which is why activity can extend beyond a single corner of a property.
Source: UC Statewide Integrated Pest Management, Rats, updated June 2025
3 to 5
litters per year are typical for roof rats, with up to 8 offspring in a litter.
This reproduction figure helps explain why early evidence is worth taking seriously, especially where food and shelter remain available.
Source: UC Statewide Integrated Pest Management, Rats, updated June 2025
20+
offspring can be successfully weaned by an average female Norway rat in a year.
UC IPM reports 4 to 6 litters annually and a nightly foraging range that can vary from 100 to 500 feet, depending on local conditions.
Source: UC Statewide Integrated Pest Management, Rats, updated June 2025
House mice
Small openings and fast reproduction matter.
¼ inch
is the height of a gap a house mouse can squeeze under.
CDC urban rodent guidance advises keeping structural openings below ¼ inch to exclude adult mice. A careful inspection looks at vents, utility lines, doors, and other transitions.
Source: Centers for Disease Control and Prevention, Conducting Urban Rodent Surveys
5 to 10
litters a female house mouse may have in a year.
UC IPM reports about 5 or 6 pups per litter when food and shelter are plentiful, and sexual maturity can begin 5 to 6 weeks after birth.
Source: UC Statewide Integrated Pest Management, House Mouse, revised July 2025
Public health context
Safe cleanup deserves attention, without panic.
890
laboratory-confirmed hantavirus disease cases were reported in the United States from 1993 through the end of 2023.
CDC describes hantavirus disease as rare, while emphasizing that exposure to rodents and rodent-contaminated materials should be handled thoughtfully. Deer mice are the most common U.S. source of hantavirus pulmonary syndrome.
Methodology and sources
Figures are shown as reported by the original source. National housing data describe the United States, while UC guidance provides California-specific context on common rats and house mice. These numbers are not an estimate of activity at any individual home.
- U.S. Census Bureau and HUD: 2023 American Housing Survey, Housing Quality
- UC Statewide Integrated Pest Management: Rats, updated June 2025
- UC Statewide Integrated Pest Management: House Mouse, revised July 2025
- CDC: Conducting Urban Rodent Surveys
- CDC: Reported Cases of Hantavirus Disease, updated April 2026
Cite this page
Nex Critter Control LLC. “Rodent Statistics and Facts for California Homeowners.” Updated October 9, 2026. https://nexcrittercontrol.net/rodent-statistics
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