The swimming warning that was in place for Pandora Pond in Napier was downgraded to "caution advised" on Tuesday.
The Hawke's Bay District Health Board's medical officer of health, Dr Nicholas Jones, said the swimming warning was downgraded after consistent water sample results that were within safe recreational water guidelines.
Dr Jones said a decision had been made to leave the pond at a cautionary status as levels could fluctuate after heavy rain.
"On balance we believe the chances of illness from swimming, sailing or kayaking at Pandora are low, providing people avoid using it for three days after rainfall."
"Caution advised" means that overall the pond is considered a moderate infection risk.
People should avoid swimming in the water for at least two or three days after heavy rain or if the water appears discoloured.
The pond has been closed and reopened several times throughout the summer after high bacteria readings.
Last week Pandora Kayaks owner Van Chan Jack was pleading for something to be done to reopen Pandora Pond as its closure had stung his business so badly he couldn't pay rent.
Hawke's Bay Regional Council senior coastal quality scientist Anna Madarasz-Smith said the council had done extensive sampling from the railway bridge to the inner harbour and had not yet found the source of the contamination that closed the pond most recently.
However it was working on what the contributing factors could be.
"Some avian, or bird contamination has been found but that would be expected in an estuary such as Ahuriri and [the council] certainly doesn't have the full picture yet," said Ms Madarasz-Smith.
She said further test results are expected within the next month, which may help shed some more light on the issue.
Dr Jones said several factors had most likely contributed to the contamination such as bird droppings, high numbers of people using the pond over hot summer days resulting in reports of human excrement (for example, dirty nappies) and stormwater discharges related to heavy rainfall.
He said because the council's annual monitoring season had now finished for summer people needed to always check fresh waterways before swimming in them and avoid them after heavy rain.
"A quick test that people can do on the spot to check the water is clear is to see whether their feet are visible when knee-deep in the water. It is also a good idea to check one of the weather websites for local rainfall information over the last few days," he said.
People can visit the council's website www.hbrc.govt.nz or the https://www.lawa.org.nz/ for water quality information on fresh waterways and swimming.