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Is it Safe to Swim?

Is it Safe to Swim?

During summer, Wellington’s regional, city and district councils monitor the quality of water at popular beaches and rivers each week. Toxic algae, which can be dangerous for dogs, is also monitored at river sites.

Check our interactive alert map for the latest alerts.

If you notice a problem with water quality then you can report it to us on 0800 496 734.

How you can stay safe

Protect yourself and your family by being aware of a couple of key things that affects water quality and can make it unsafe for swimming.

Wait for two days after rain before you swim again

Water quality in our rivers and at our beaches is generally pretty good over the summer, except in poor weather conditions.

Heavy rain flushes contaminants from urban and rural land into waterways and we advise you not to swim for at least two days after heavy or prolonged rain – even if a site generally has good water quality.

Find out more about swimming after rain.

Toxic Algae

Toxic algae (known scientifically as cyanobacteria) are an ancient group of photosynthetic bacteria. Toxic algae are widespread in rivers (and lakes) in New Zealand, including waterways with very good water quality.

Most of the year toxic algae is present at normal background levels and not much of a danger. But during summer, low rainfall and warm temperatures create a nice stable environment where it can thrive.

Toxic algae forms leathery looking mats on rocks in the riverbed, and ranges from blackish/brown to dark green in colour (it's quite different from normal harmless green algae, which looks bright green and often forms long strings).

These mats can come loose and wash up on the edge of the rivers, or form ‘floating rafts’ in shallow areas. As they dry out they turn light brown or white and produce a strong musty smell. This is when it poses the biggest risk to our dogs. They love the smell and many dogs will try to eat it if they get the chance.

The best thing you can do to keep yourself, your kids and your pets’ safe is to know what toxic algae looks like and avoid it. 

Find out what toxic algae looks like.

Harbours and coast

Greater Wellington Regional Council is responsible for ensuring the safety everyone who uses the harbour and coastal waters.

For more information go to the Harbour Management page.

Toxic Shellfish

The Ministry for Primary Industries tests shellfish and seawater samples around New Zealand each week to ensure they are not contaminated with biotoxins from algal blooms. Public warnings are issued when shellfish are not safe to eat.

View marine biotoxin (toxic shellfish) warnings.

National water quality trends and data

LAWA is a key resource for measuring the current state of New Zealand's waterways and shows longer-term trends, information and data.