Tests are to be carried out to see if a pond at South Wootton is harbouring algae toxic to dogs.
A post on social media claimed at least two dogs have died after they were walked on The Green.
South Wootton Parish Council has placed notices around the common advising dog owners to “stay clear of the pond”.
Moira Kirby, assistant clerk at the parish council, said: “We have contacted the Environment Agency and environmental health at the borough council to get the water tested.
“We are dog lovers ourselves and hopefully the matter will be resolved soon.”