Water quality standards and bathing area classification : Example

	Parameter	Excellent quality	Good quality	Sufficient quality	Standard analysis methods
1	Intestinal enterococci (UFC/100ml)	200 *	400 *	330 **	ISO 7899-1 or ISO 7899-2
2	Escherichia coli (UFC/100ml)	500 *	1000 *	900 **	ISO 9308-3 or ISO 9308-1

* assessment to 95th percentile.
** assessment to 90th percentile.

 

	Intestinal enterococci
E s c h e r i c h i a c o l i		Percentile 95 < 200	200 < Percentile 95 < 400	Percentile 95 > 400 and Percentile 90 < 330	Percentile 90 > 330
	Percentile 95 < 500	Excellent	Good	Sufficient	Poor
	500 < Percentile 95 < 1000	Good	Good	Sufficient	Poor
	Percentile 95 > 1000 and Percentile 90 < 900	Sufficient	Sufficient	Sufficient	Poor
	Percentile 90 > 900	Poor	Poor	Poor	Poor

	Parameter	Excellent quality	Good quality	Sufficient quality	Standard analysis methods
1	Intestinal enterococci (UFC/100ml)	100 *	200 *	185 **	ISO 7899-1 or ISO 7899-2
2	Escherichia coli (UFC/100ml)	250 *	500 *	500 **	ISO 9308-3 or ISO 9308-1

* assessment to 95th percentile.
** assessment to 90th percentile.

 

	Intestinal enterococci
E s c h e r i c h i a c o l i		Percentile 95 < 100	100 < Percentile 95 < 200	Percentile 95 > 200 and Percentile 90 < 500	Percentile 90 > 500
	Percentile 95 < 250	Excellent	Good	Sufficient	Poor
	500 < Percentile 95 < 500	Good	Good	Sufficient	Poor
	Percentile 95 > 500 and Percentile 90 < 500	Sufficient	Sufficient	Sufficient	Poor
	Percentile 90 > 500	Poor	Poor	Poor	Poor

Compliance with quality thresholds on  Escherichia coli		Compliance with quality thresholds on intestinal enterococci
Excellent quality (Percentile 95 of analysis findings)	no	Excellent quality (Percentile 95)	no
Good quality (Percentile 95 of analysis findings)	yes	Good quality (Percentile 95)	no
Sufficient quality (Percentile 90 of analysis findings)	yes	Sufficient quality (Percentile 90)	yes

In this example, illustrated by the following graphs, the quality threshold attained by both E. Coli and intestinal enterococci is in the "sufficient" range.