# Huron County Health Unit, Beach Testing annual summary

## E.coli bacteria per 100 mL of water

In accordance with Province of Ontario standards, samples are taken
at five different spots at a beach, and the geometric mean of those five
samples is computed. The Province considers that a geometric mean of 100
or less for the day's five samples is acceptable. This graph shows the
annual geometric mean of the daily geometric mean, for each beach, for
each year since 1996.

**Note**: The geometic mean (the nth root of the product of n
values) minimizes the effect of large values that are present in the
data.

Maintained by Roger Watt, ACLA Steering
Committee. Last updated 2008-05-22.