What we measure

We measure the number of enterococci bacteria in coastal water. 

  • Enterococci are bacteria that naturally occur in the gut of humans and animals as well as birds, fish and reptiles.
  • In water used for swimming and other recreation, low counts of enterococci are acceptable, but too much contamination can cause gastroenteritis or infections of ears, eyes, nasal cavity, skin, and the upper respiratory tract.
  • Enterococci are counted under the microscope as Colony Forming Units (cfu) per 100 mL.
  • When enterococci are detected above 280 cfu per 100 mL (in two consecutive samples within 24 hours), swimming is not recommended.

Find out more about monitoring results here: 

And enterococci testing here: 

Testing programmes

There are three testing programmes carried out in Titahi Bay, all of which help us understand water quality and where any contamination is coming from.


  • To assess whether Titahi Bay is safe for swimming, on behalf of Greater Wellington Regional Council, we take measurements as part of the LAWA safe to swim sampling programme (which we call Baywatch). These samples are taken knee-deep in the sea (0.15 metres from the surface). 
  • We have been doing an additional round of Baywatch sampling and putting the results on our website, here.

 Stormwater outflow

  • We also take samples at the outlet of the South Beach Access Culvert, to help us understand what’s coming out of the stormwater network.

 Wastewater Treatment Plant monitoring

  • The Wastewater Treatment Plant operates in line with rules set by Greater Wellington Regional Council in the plant’s resource consent.
  • One of the rules is that water quality must be monitored monthly at six shoreline locations along the coast, including Titahi Bay Beach. If there is an incident at the plant, for example wastewater bypasses or ‘skips’ one part of the treatment process or there is an overflow, then samples are taken at or about 24 hours, 72 hours, and 144 hours after. 

These samples are collected and analysed by an independent lab to the satisfaction of the regulator, Greater Wellington Regional Council. The most recent annual report is available on the Wellington Water website