"The Ahuriri Estuary has not been contaminated from runoff from farmland; it's been contaminated from urban runoff.
"It's very easy to blame the farmers, but there's a lot of freshwater challenges, and they're not all rurally based.
"I doubt there's a household in New Zealand that hasn't poured water-based paint down the sink to get rid of it, as an example. Those types of actions, that everybody does, they actually have to stop if we're going to have a fair go at fixing this."
Mr Yule also urged pragmatism and appropriate timelines for farmers to meet regulatory requirements.
"We've got to [clean up] in such a way . . . that it means it can change but they can stay in business."
Labour's environment spokesman, David Parker, announced the party's freshwater policy in Havelock North on Friday night, alongside Tukituki candidate Anna Lorck and Napier MP Stuart Nash.
At the policy's core is a new National Policy Statement (NPS) for Freshwater Management.
Under the NPS, any further increases in farming intensity, including more livestock, irrigation or fertiliser per hectare, would no longer be a "permitted activity".
The new NPS would also require rivers and lakes be clean enough for people to swim in during summer without getting sick.
It also includes sections on improving urban stormwater and sewage treatment. It's understood Labour would unveil a more comprehensive freshwater policy closer to the September 23 election.
Federated Farmers Hawke's Bay provincial president Will Foley said it appeared the measures relating to farms were already in place.
"I think they're just trying to bring in more rules and regulation when there are already things in place that cover that . . . Feedlot farmers need to get a consent, so I'm not quite sure why he think some new rule needs to be created around that."
But Mr Foley too said it was not only farmers who needed to decrease their environmental impact.
"We certainly do accept it is a whole community approach to this.
"My question to Labour is, are they looking at the same thing that comes to immigration, and expansion of cities, and things like that? Are they being placed under the same rules and regulations?
"[Farmers] just want to know that people accept there are other people, industries and urban populations that do have an effect and see everyone doing their bit.
"We don't want to feel like we're the only ones who are made to spend money and do things to improve."
