Council uses the 'BatheWatch' software provided by the Ministry for the Environment to assign SFR Grades.
See the Ministry for the Environment BatheWatch user guide
There are two components to the assignment:
SIC (Sanitary Inspection Category)
The SIC is based on the assessment of potential sources of faecal contamination that could have an impact on the water quality of a site. The key steps are:
- Identifying potential pollution sources. Pollution sources include pastoral land use, sewage storage and treatment systems, large numbers of aquatic birds and feral animals.
- Determining the likelihood of each source affecting the site. For each pollution source the potential of causing high indicator bacteria concentrations at the site is considered.
- Assign a SIC. The SICs are categorized as very low, low, moderate, high or very high.
MAC (Microbiological Assessment Category)
The MAC is based on the actual indicator bacteria concentrations that have been measured over five summer season at a site. The statistic used for the calculation of the MAC is the upper 95th percentile.
Find out more about indicator bacteria
Find out more about MAC calculation
The table below shows the MACs and the associated values for the two indicator bacteria:
MAC
(microbiological Assessment Category)
| Coastal
Enterococci/100 mL*
| Freshwater
E.coli/100 mL*
|
|---|
| A
| <41
| <131
|
| B
| 41 - 200
| 131 - 260
|
| C
| 201 - 500
| 261 - 550
|
| D
| >500
| >550
|
* Upper 95th percentile (95%ile) of routine sampling over five consecutive summers.
