The following characterizes a Blue Flag beach:
The beach is clean and inspected regularly
There is clean water and information about the current water quality
The beach has a duty to take the Blue Flag down by acute pollution
Clean toilet facilities and well maintained buildings
There are waste disposal contractor
The beach has life saving equipment, first aid box and (emergency) telephone nearby
This and much more is to make the beach for a good and safer place to be.

Read more on the Blue Flag website