That is great for the environment but less so for water quality because all the contaminants get more concentrated.
The dirt on our cars is a mixture of dirt and bird droppings and can contain a variety of bacteria, normally disinfectants are automatically dosed to ensure these bacteria do not increase to dangerous levels.
Regular checks on bacteria levels is an essential measure to monitor that the system is operating safely.
These tests include a general bacteria count plus a specific test for legionella. Legionella testing is essential due to the enormous amount of aerosol produced during the cleaning process.