Local councils, the Environmental Protection Authority and the Derwent Estuary Program collect water samples from 35 sites throughout the Derwent estuary each Tuesday from the start of December to the end of March.
Water samples are analysed for specific bacteria (enterococci) which indicate the presence of contaminants from stormwater run-off and other sources. Each site is classified as having Good, Fair or Poor water quality in accordance with state and national guidelines, based on five years of data.
What the gradings mean:
- Good: Water quality is usually good for swimming.
- Fair: Water quality is usually fair for swimming, but occasionally requires retesting.
- Poor: Swimming is not advised.
For health and safety of all members of the public, swimming in the Derwent is not recommended for two days after heavy rain (more than 10mm of rain over a 24-hour period), and never in the vicinity of stormwater pipes or urban rivulets.
Further information and up-to-date data on beach water quality can be found at the Derwent Estuary Program website here.