A new study has put California in the spotlight — and not in a good way. Out of more than 300 major U.S. cities ranked from most to least dirty, four California cities landed in the top 10, including the No. 1 spot.
The ranking comes from LawnStarter, a national lawn care company, which analyzed data from 303 of the country’s largest cities. The study evaluated cleanliness using four key categories: pollution, living conditions, waste infrastructure, and how dissatisfied residents are with their environment.
Metrics included everything from the number of public restrooms and junkyards to population density and average air quality. Each factor was weighted based on its impact on overall cleanliness.
So, which cities are struggling most with grime and grit? Here's what to know about LawnStarter's study.
What are the dirtiest cities in America?
San Bernardino was named the dirtiest city in California and the country, and ranked at the top overall in resident dissatisfaction and pollution. Los Angeles placed closely behind at No. 2.
Ontario was the fourth dirtiest city, and Corona capped off the top 10 at No. 10.
Other California cities that held notable positions include Pleasanton, which ranked low in the dirtiest cities category at No. 295. Newport Beach, Simi Valley, and Corona were among the 10 cities with the most waste in landfills per 100,000 residents.
According to the study, 10 California cities were tied for the worst air quality, with an Air Quality Index score of 97.
San Bernardino
Ontario
Corona
Fontana
Riverside
Victorville
Murrieta
Temecula
Rancho Cucamonga
Apple Valley
Ranking the top 10 dirtiest California cities
1. San Bernardino: Highest in pollution and resident dissatisfaction
2. Los Angeles: High near-roadway pollution and overcrowded housing; AQI score of 75
3. Ontario: Tied for worst air quality; high pollution dissatisfaction
4. Fontana: Part of San Bernardino County cluster; ranked No. 19 nationally
5. Victorville: Ranked No. 30 nationally
6. Rancho Cucamonga: Ranked No. 121 nationally
7. Apple Valley: Ranked No. 134 nationally
8. Corona: Previously ranked No. 10 nationally; high landfill waste per capita
9. Riverside: AQI tied at 97
10. Temecula: Among 10 cities with worst AQI
What are the 10 dirtiest cities in America?
Lawstarter found these cities fared poorly in the dirty city categories
No. 1- San Bernardino, California
No. 2- Los Angeles, California
No. 3- Detroit, Michigan
No. 4- Reading, Pennsylvania
No. 5- Ontario, California
No. 6- Newark, New Jersey
No. 7- Phoenix, Arizona
No. 8- Jersey City, New Jersey
No. 9- Las Vegas, Nevada
No. 10- Corona, California
Ernesto Centeno Araujo covers breaking news for the Ventura County Star. He can be reached at [email protected], 805-437-0224 or @ecentenoaraujo on Instagram and X.
This article originally appeared on Palm Springs Desert Sun: California Cities Lead 2025 Dirtiest List with San Bernardino at No. 1
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