Can I swim here? Check the water quality before you get in

Father with son swimming in river

 We monitor over 100 swim sites to keep you informed.

Each summer from November to March, we monitor more than 100 of Canterbury’s popular swimming sites weekly to check for water quality issues that can be harmful to people and pets, especially dogs.

Canterbury has some stunning swim spots to cool off during our hot summers, but it’s important to be aware of water quality issues and how to stay informed.

Check the water quality for over 100 popular swim spots before you get in, to keep you and your whānau safe.

We’ll be sharing some top tips on where it is good to swim during summer via our facebook page so keep an eye out for summer inspiration.

Weekly monitoring can be accessed via LAWA

We monitor water quality at popular river, lake, and beach swim spots each week so up-to-date information is available and you can make decisions about where is good to swim to avoid becoming ill.

It’s easy to find water quality for any monitored swim site in Aotearoa on the Land Air Water Aotearoa (LAWA) website, under the ‘Can I swim here?’ section. Water quality can change, so it’s important to check first, before heading out.

LAWA logo

 Check up-to-date water quality information on the LAWA website.

We monitor for E. coli and cyanobacteria (toxic algae) at freshwater (lakes and rivers) sites, and enterococci bacteria at coastal sites.

If the results show the water at a site has changed and may be unsuitable for recreation, Canterbury District Health Board or South Canterbury District Health Board will issue a health warning for that site and it will be listed on our ‘Health Warnings’ page and the LAWA website.

If a site is generally unsuitable for swimming, permanent signage should be erected at the site.

Know what to look for


Watch this video

Watch this video about cyanobacteria.

Cyanobacteria is a naturally occurring blue-green algae with the potential to bloom and may produce toxins that can harm people and can kill pets.

Blooms form when cyanobacteria grow quickly, usually due to changes in environmental conditions such as warmer temperatures, sunlight, high levels of nutrients, or stable river flows.

In rivers, cyanobacteria (called benthic cyanobacteria) grow on the bottom of riverbeds. It appears as thick dark brown or black mats that have a slimy or velvety texture and a strong musty smell. These mats can detach and gather at the rivers edge. 

In lakes, ponds and lagoons, cyanobacteria (called planktonic cyanobacteria) are suspended in the water. Water can look cloudy, discoloured, or like it has small globules in it. Some planktonic cyanobacteria may not have obvious visual traits.

If in doubt, keep them out

Dog in river

 Dogs love the musty smell of toxic algae. If in doubt, keep them out.

Unfortunately, dogs love the musty smell of cyanobacteria and are naturally drawn to investigating it – usually by eating or licking the material.

Not all algae in our rivers and lakes are harmful but if you are in any doubt about the water quality, then keep your dog on a leash and away from the water.

Symptoms of poisoning in dogs usually occur within 30 minutes. These include panting, lethargy, muscle tremors, twitching and convulsions.

If your dog is showing these symptoms after being in contact with a waterway, contact a veterinarian immediately. You or your vet can report any animal illness resulting from contact with cyanobacteria to us.

Six tips to stay safe this summer

  1. Check water quality information before swimming on the Land Air Water Aotearoa (LAWA) website.
  2. Avoid swimming for 48 hours after heavy rain or prolonged rainfall.
  3. Follow any warning signs.
  4. Know how to look out for cyanobacteria (toxic algae) and if in doubt, keep out.
  5. Avoid eating fish and shellfish taken from areas where health warnings are in place. Boiling food and water does not remove the toxins from cyanobacteria.
  6. Stay away from potential contamination site such as pipes, culverts, and flocks of birds.