A stormwater pipe is leaking into the Tyne Stream.
It's a problem because the stormwater system is usually only under pressure when it is carrying rainwater. And it's not raining.
Fifteen minutes into a two-hour tour of Napier's stormwater system, and Napier City Council's Environmental Solutions team had to jump into action.
They found sediment, sawdust and rust had been carried into the Tyne Stream and ultimately, out to Ahuriri Estuary, all of which had a negative impact on water quality and wildlife in the area.
So much sediment has built up in the stream, that despite it being a concrete-lined channel, it is easy to become stuck ankle deep in mud.
Unfortunately it is a common sight for manager Cameron Burton and his team, who are out and about each week checking the waterways.
They see everything: plastics, polystyrene, and in one case about 1000 litres of caramel, spilled into the city's waterways.
The caramel case ended with a $1000 infringement notice, and Hawke's Bay Regional Council abatement notice to cease discharge. Clean-up costs were also recovered in full.
Napier City and Hawke's Bay Regional councils have combined to produce a $50,000 campaign to educate locals (industry included) about the problems washing anything that is not stormwater down the drains can cause.
Because it all ends up somewhere, and that somewhere is the Ahuriri Estuary.
The main message from the campaign? Only rain goes down the drain.
At the next stop on our tour it was easy to see why the message needs to be sent.
A build-up of grass, plastic bottles, toys, and polystyrene clog a pump station grate. A week ago, it had been cleared.
Burton says every time he visits the pump station, without fail, there is a ball pit ball - as in a ball from a children's ball pit play area - caught in the grates.
While the grates filter rubbish out of the stormwater, they do not catch everything such as small, polystyrene balls.
Environmental Solutions team member Hannah Ludlow said the grates cannot be made smaller, as it would impede the ability of fish to swim through the waterways, having a negative impact on the environment upstream.
Burton said putting nets on outlets was a popular suggestion, but that system was expensive and had not been widely trialled.
And if a net full of plastic came loose, it could stop the pumps working effectively.
It is also an "ambulance at the bottom of the cliff" solution.
"We shouldn't need nets to catch plastic because there shouldn't be plastic within the stormwater."
Our next stop on the tour was Lagoon Farm, a piece of council-owned land off Prebensen Drive which has the potential to be used as a filtering wetland.
If built it would be similar in size to wetlands in Europe, and the largest in the Southern Hemisphere, well over 200 hectares.
Burton said wetlands help filter sediment out of the water, a bonus as sediment particles tended to collect other things like zinc, covering everything in the estuary and making it toxic for wildlife.
Everything upstream of the wetland, which included the Onekawa industrial area, would have to be strictly controlled if the wetlands got the go ahead.
"So no metals ... as soon as you get a flush of metals, that's a section of the wetland dead, that's too much for plants," Ludlow said.
The final stop on the tour was the discharge points, located near Hawke's Bay Airport.
During high tide the massive gates are shut so the city doesn't flood, and get pushed open by the pressure of the pumps working at low tide.
Burton says they often have to answer questions from people wondering why water has to be pumped to the estuary.
The answer is that parts of Napier are either at or below sea level.
If the city stopped pumping water, Napier might end up as a southern hemisphere Venice.
The Napier council is working to improve the estuary, the possible wetlands are one example, and the city's district plan is also under review.
But the easiest way to improve the water quality immediately is for everyone to look at their own actions.
Small actions, such as washing your car on your lawn rather than driveway, not dropping your cigarettes down the drain and putting your recycling out the morning of collection day can all have a big impact.
Remember - only rain goes down the drain.