Samples taken from Shubenacadie Grand Lake show evidence of blue-green algae consistent with levels found to be dangerous to dogs.
However, the Department of Environment is waiting for lab results to see if pesticides or other contaminants are in the water.
Residents are still advised not use the water from the lake and the same goes for pets.
An investigation was launched after two dogs died after being around the water and a woman was hospitalized last week.
Officials say homeowners should not draw their water from lakes or rivers in general, as typical home treatment systems only provide protection against bacteria in the water and do not typically treat algae toxins, petroleum products, pesticides or other chemical contaminants.
Initial rapid water tests on Thursday, June 10, were inconclusive. Targeted sampling done the next day with the assistance of a drone confirmed the presence of blue-green algae.
Blue-green algae can appear at any time and has a musty smell, particularly in warm water or water with a lot of nutrients.
The province is asking anyone who sees a blue-green algae bloom to contact one of the department’s regional offices.
At this time, department staff do not believe that properly constructed and regularly tested wells are affected.
