When visitors travel to a new city, how clean a place is or isn’t can affect their overall opinion of the area.
A new study from Oxi Fresh Carpet Cleaning ranked the 35 largest metropolitan areas in the United States based on their cleanliness. The results were based on factors such as tap water quality, percentage of pests in the area and the number of days in a year that the air quality was considered good.
One of Arizona’s largest cities made the list of top 10 cleanest areas, and it might surprise you. Here’s which city in the Grand Canyon State ranked ninth overall for cleanliness, and where other U.S. cities placed.
How were the cleanest places determined?
Oxi Fresh used seven cleanliness factors to rank each metro area on a scale of most to least clean, represented by a letter grade between A+ and D.
The results came from an analysis of the largest U.S. metro areas using the most recent data from the Census Bureau’s American Housing Survey.
Each metro area could earn up to 100 points for each of the seven factors, which were then totaled to find the cleanliness score and converted to a letter grade.
Population density: The number of people per square mile. According to Oxi Fresh, a higher concentration of people can lead to increased pollution, poorer air quality, greater strain on infrastructure and more complicated waste management.
Rodents: The percentage of housing units with signs of mice, rats or other rodents inside the home between April 2024 – 2025.
Cockroaches: The percentage of housing units with signs of cockroaches inside the home in the past year.
Vandalism: The percentage of homes without vandalized or abandoned buildings within a half-block radius.
Litter: The percentage of homes without litter, trash or “junk” on the streets or properties within a half-block radius.
Air Quality: The number of days in 2024 that the daily Air Quality Index values were classified as “good” (values of 50 AQI or less) for all AQI pollutants: CO, NO2, Ozone, PM10 and PM2.5.
Tap Water Quality: The average number of different types of contaminants detected in the metro area’s drinking water that exceeded the Environmental Working Group’s health guidelines.
Another view: Phoenix ranked 6th dirtiest city in US by new study. Here’s why
Metro Phoenix is 9th cleanest US city
Metro Phoenix made Oxi Fresh’s list of top 10 cleanest cities in the United States and received a good grade. Here’s how Oxi Fresh ranked the Valley:
Population density: 348 people per square mile
Air quality: 24 days of good AQI index scores in 2024
Tap water quality: 8.5 contaminants
Top 10 cleanest cities in the U.S.
These are the cleanest cities and metropolitan areas in the United States and their cleanliness grades, according to Oxi Fresh.
Portland and the surrounding areas of Vancouver and Hillsboro, Oregon: A+
Seattle metropolitan area: A
Detroit, Warren and Dearborn, Michigan: B+
Minneapolis metropolitan area: B+
Denver and surrounding area: B
Phoenix metropolitan area, including Mesa and Chandler: B
Kansas City, Missouri and Kansas: B-
10 dirtiest cities in the U.S.
Out of the largest metro areas in the U.S., these are the cities that Oxi Fresh determined were the least clean and their cleanliness grades.
New York, Newark and Jersey City metro areas, New York/New Jersey, D
Los Angeles, Long Beach and Anaheim metro areas, California, D+
Philadelphia, Camden and Wilmington metro areas, Pennsylvania/New Jersey/Delaware/Maryland, D+
Houston, Pasadena and The Woodlands metro areas, Texas, C-
Washington, Arlington and Alexandria metro areas, Washington, D.C./Virginia/Maryland/West Virginia, C
Chicago, Naperville and Elgin metro areas, Illinois/Indiana, C
Dallas, Fort Worth and Arlington metro areas, Texas, C
Cincinnati, Ohio/Kentucky/Indiana, C+
Oklahoma City, Oklahoma, C+
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This article originally appeared on Arizona Republic: Is metro Phoenix clean or dirty? See what new study says