Summer season monitoring
LAWA shows the best available water quality information to help you decide where to swim. For many sites there are two types of information available, the weekly sampling result and the overall bacterial risk.
Weekly sampling result
The weekly sampling result is a snapshot in time and is a guide to the recent water quality at this site.
Overall bacterial risk
Overall bacterial risk is important to consider. Based on 3 years of data it is a guide to the general water quality at this site.
See factsheets for more information.
What do the icons mean?
Summer season monitoring history
E. coli sampling graph
- Samples this season
- Samples from last 3 years
Keeping your dog safe and healthy this summer
A trip to a lake is a lot of fun and knowing how to keep your dog safe means you are able to relax and enjoy the adventure even more. Potentially toxic algae can be harmful to dogs (and us) – this section shows you what to look for.
What to do
The best thing you can do to keep yourself, your kids and your dog safe is to know what potentially toxic algae looks like and avoid it.
If you are not sure, keep your dog on a lead at a lake and don’t let them in or near the water. Bring water from home for your dog so that they don’t need to drink out of the lake.
What is potentially toxic algae?
Potentially toxic algae, known scientifically as cyanobacteria, are naturally occurring in rivers and lakes in New Zealand, including waterways with good water quality. Most of the year it is present in lakes at low levels that are not much of a danger. But algae can be a problem during the summer months, when warm temperatures and nutrients in the lake create an environment where it can thrive, forming extensive blooms which can be toxic to humans, dogs, livestock and wildlife.
Scientists do not yet understand when and why this algae turns toxic, so to be safe, always treat it as toxic.
Dogs are particularly susceptible to poisoning from toxic algae as they may drink lake water or play in the water.
What to look for
Potentially toxic algae grows within the water column in lakes and cause the water to become murky or cloudy.
These free floating algae blooms in lakes are generally green in colour and can look like paint, petrol or pea soup. It can also form foam or scum on the water’s surface, especially at the water’s edge.
Regional Council staff monitor for these mats in lakes where blooms are known to occur. Blooms can occur very suddenly (within an hour) so please alert your regional or unitary council if you notice a new algal bloom in a lake.
What if my dog has eaten potentially toxic algae?
If you suspect that your dog has eaten toxic algae, you should contact your vet as soon as possible. Signs a dog has been poisoned by toxic algae include lethargy, muscle tremors, fast breathing, twitching, paralysis and convulsions.
Find out more about potentially toxic algae here
Site suitable for these activities and has these facilities
Our lakes, rivers, and beaches are great natural playgrounds but they can be unpredictable. Be aware of other potential risks such as rips, strong currents, sudden drop offs, or underwater objects before jumping in. LAWA recommends that you avoid swimming for 2 - 3 days after heavy rainfall and follow the advice of any warning signs in place.