Wash USA raises money for the Make a Wish Foundation and has raised more than $400,000 since it started four years ago.
The group aims to raise over $300,000 this year.
Last year, more than 775 carwash operators and 23 industry sponsors participated.
To find a participating car wash, go to Washesforwishes.org.
For more about the Make-A-Wish Foundation, go to Wish.org.