Stopping the flow of pollutants into urban Whangarei's 6000 stormwater traps and planting trees along the waterways could all help improve the water quality in the Hatea, according to a local environmentalist.
On Sunday, 38 people jumped into the Hatea for Take The Plunge, while 173 people signed a petition which would be presented to the Whangarei District and the Northland Regional Council (NRC) asking that councils maintain good water quality in the harbour.
One of the first to take the plunge was Jess White, owner of the Butter Factory, who at 37 weeks pregnant was more than happy to jump in after clearing it with her midwife and NRC testing had the site as safe to swim in.
Ms White said being heavily pregnant received a fair bit of attention so she was delighted to be able to use it to raise awareness about the harbour.
''I just think this is a really good cause. I wouldn't have done it if I wasn't sure it was safe [for her and her daughter, due on December 10]. If me being pregnant can raise awareness of the issue then that's great,'' she said.
''I think we should all be doing something about the water quality in our harbour.''
Nicki Wakefield, co-ordinator of Whitebait Connection, and its Drains to Harbour Programme, said on Sunday that the local mountains, Hurupaki and Parakiore in Kamo, were the source of the water in the River Hatea.
The water flowed over the Whangarei Falls, travelling through Tikipunga from springs in Glenbervie Forest.
"On its way down, there are a number of issues impacting on the water quality," she said.
The Drains to Harbour stormwater awareness project is funded by Whangarei District Council (WDC) and educated people about what runs down the drains and enters the waterways.
"Most [water] will have travelled from the streets of Whangarei into the stormwater drains and out into the harbour, along with unseen pollutants like oil from cars, sediment and detergents."
"We're all responsible for what enters the drains and makes it way into the harbour."
The Waitaua Awa Restoration Project is organised by the council-funded Mountains To Sea Conservation Trust and planting plants to improve the water quality further upstream.
The plants would shade the water from the sun, which encouraged the growth of algae.
She commended the work of pollution campaigner Millan Ruka in raising awareness of the effect stock had on water quality.
WDC supported the Mountains To Sea Conservation Trust in restoring the Waitaua Awa (River) and aimed to plant 10,000 trees in the Gillingham Rd Reserve in Tikipunga this year.
Take The Plunge organiser and TogetherTahi member Hannah White said the harbour issue was raised when her political colleagues Ash Holwell and Matt Keene were running for office in the local elections.
She said she had a vision of students finishing school and diving into the harbour for a swim.
"We live in paradise. We have amazing, beautiful beaches but they are a drive away."
She said Take The Plunge would be an annual event and would, hopefully, hold local authorities to account for maintaining a clean harbour.