Drinking water quality

The Council maintains a water quality programme that tests Wellington's drinking water supply every month.

Safe drinking-water is a necessity for good health. Wellington Water is engaged to ensure that water in the Wellington region is safe and meets the requirements of the drinking water standards.

For more information about drinking water requirements visit the the Ministry of Health website.

Run the tap before drinking

Some plumbing fittings allow tiny traces of metals to build up in water that has been sitting in the tap for several hours.

So, although the health risk is small, the Ministry of Health recommends that you flush a cupful of water from your tap each morning to remove any metals that may have dissolved from the plumbing fittings.

You should do this, whether or not you are on private or public water supply.

If you are a landlord make sure that your tenants are aware of this advice.

For more information, contact:
Drinking Water Assessment Unit
Wellington Regional Public Health Service
Phone: 04 570 9002

Water testing

The Council is serious about providing clean, safe drinking water. We maintain a rigorous water quality programme that tests over 100 samples each month.

Our programme complies with the Ministry of Health's Drinking Water Standards for New Zealand 2005 (Revised 2008).


The Wellington water supply is sampled and analysed by Environmental Laboratory Services, an independent IANZ accredited laboratory.

Water samples are tested for:

  • E.coli (Escherichia coli) - an important indicator of potential contamination and disease - total coliforms and heterotrophic plate count. E.coli testing is required for compliance.
  • Chemical levels - chloride, fluoride and water 'hardness' (the amount of naturally occurring minerals in water), colour, conductivity, free available chlorine, temperature and turbidity.

The city is divided into 11 water supply zones. Within each zone, samples are taken from several different sites on a weekly schedule. Each water supply zone is sampled at different points with the largest zones sampled every 3 days and the smallest every 6 days.

The Council has 18 bulk water supply points where water arrives in the city from the treatment plant. Ten supply points are tested weekly for E.coli and chemicals. Two main bulk water supply pump stations are tested daily for chemicals and E.coli, averaging over 100 tests per month.


In the 2015/16 financial year, all samples taken complied with the Ministry of Health's Drinking Water Standards for New Zealand 2005 (Revised 2008).