The water body, known as Lowes Pit (or Lowes Lake) on property owned by the Hastings District Council at 15 Hazelwood St, is part of the Heretaunga unconfined aquifer and is within the Frimley Bore source protection zone.
Lowes Pit is within one kilometre of 13 bores used for food processing, irrigation and drinking water supplies.
Hastings District Council group manager asset management Craig Thew said it is not the first time they have been notified about the "potential risk".
Council itself highlighted this potential risk as part of its wider assessment of catchment risks, Thew said.
"It has been reviewing this site along with others in the wider area."
The latest results show conformance with NZDWS limits with the exception of E.coli. In April this year, the level peaked to 11,000.
The source of E.coli has not yet been identified, but there are a range of potential sources including waterfowl in the area of the water in Lowes Pit.
Under the current Regional Plan rules, the discharges of stormwater is a controlled activity and consent must be granted for controlled activities. In this case, it was granted on November 1, 2017, and will expire on May 31, 2022.
The annual consent report has been sent to HBRC and is being reviewed.
The lake is believed to have originally been one of several shingle pits established by Peter Lowe to build roads for the Hastings, Havelock North and Napier councils, in the 1940s.
Research suggests that over time, the pit, 10,800sq m surface area and about 6.5m deep, had filled with water from the aquifer, connected to the Ngaruroro River.
Road runoff (storm-water) contaminants such as sediment, zinc, copper, oil and grease are currently being discharged into the water body.
Harvey has gone public with his concerns after meeting with a local resident who wrote to him, asking for "positive action". The resident wrote to 31 people including Hazelhurst, the HBRC, HBDHB, iwi and the Minister of Health David Clark on August 14, 19 and 26 of this year.
"It is Hastings council's responsibility to act with urgency," Harvey said.
He plans on asking council to advise what their legal obligations are under the Health Act.
Harvey said one of Hazlehurst's campaign platforms was making drinking water her "top priority" and she should act over the lake.
"Look at what happened in Havelock North where council ignored the warning signs and failed to inform the public. We can never afford to let any risk go unknown again," Harvey said.
Hazlehurst said that while the risk of contamination of the aquifer by the water in Lowes Pitt is "very small", they do still consider it a risk and it is being addressed.
"The groundwater complies with the drinking water standards, which is actually very good for water that is on the surface. We are working closely with regional council on this."
She confirmed council received a letter from the resident which was copied to her. The staff informed her that they were meeting him to address his concerns.
She said this issue has been discussed at a number of public Council meetings over a long period of time, all of which Cr Harvey and members of the public have attended.
"The increased monitoring across all groundwater bodies in the catchment areas of Council drinking water bores has been dramatically increased since the Havelock North crisis vastly improved our understanding of the risks to drinking water."
