The Green Party recently launched its water policy and, before looking at what it proposes, I need to explain what's been recently gazetted.

The National Policy Statement (NPS) for freshwater may not have razzmatazz, but it arose from that exercise in consensual collaboration called the Land and Water Forum.

It was the first time industry, councils, government departments and groups from Federated Farmers to Fish & Game sat down to address openly water issues and find solutions.

At the heart of the NPS are our regional councils, who have been tasked with maintaining and improving water quality while bringing the poorest water quality up to a national minimum standard.

This policy applies to all water bodies whether they are in town or country. This was an essential part of the forum consensus and the Government chose secondary human contact as the national minimum standard.

The Green Party claims it is an advocate for the environment and I would have thought it would have welcomed this important piece of legislation, the intent of which is to keep the country's water as the best in the world.

For an objective picture, can I direct you to the Land and Water Aotearoa website which confirms our water quality is generally good, with many rivers and streams improving thanks to farmers' efforts at riparian protection.

What we know is that most swimming spots monitored by regional councils over the warmer months are generally satisfactory for swimming. The Greens often claim "60 per cent of our water" is unsafe, but a vast number of sites are affected by urban runoff.

The Green Party wants to make all water bodies swimmable. This is disingenuous because of the sheer difficulty and cost of achieving it. There are 425,000km of waterways in New Zealand which would have to meet those swimming standards, 24 hours a day and 365 days of the year.

The Landcare Trust is running a community project to clean up some of the urban streams that flow into Auckland's Tamaki River. Regardless of that effort and enthusiasm it will never be able to stop those streams from being contaminated to the extent that they will become safe for swimming.

Think of the 150-page New Zealand Standard for public swimming pools, "to ensure the risk to public health is minimised". Most small schools have had to close their swimming pools because of problems maintaining that and other standards. Trying to apply that standard to all fresh water bodies is a nonsense.

This is where the Green Party is disingenuous. When it says "all water bodies", it really means only those in the countryside because it does not wish to alarm its core urban constituency.

The Green Party ignores the huge shift in farmers' attitude towards environmental stewardship and underplays quantum leaps in management and mitigation of farm nutrients, the fencing of waterways, riparian planting, the strategic application of fertilisers and nutrient budgeting and the effects these are having on improving water quality.

The Greens continue to blame farmers.

Farmers like me acknowledge there is a lot more work we need to do and the vast majority of us are adopting practices and spending tens of millions of dollars a year which, given time, will sort out our contribution. But we are not the sole cause or the sole solution. River quality reports are already showing the benefit of a change in farmers' attitude toward environmental stewardship, but this narrative doesn't fit the Greens' script.

The NPS, in contrast, will be law. It gives communities the power to decide how much progress needs to be made and over what timeframe. It specifically encourages communities to decide what they want for their rivers and lakes while balancing that with the costs to society and the economy. The NPS may not have the sexy but implausible soundbite "swimmable for all", but it gives that choice to the community. It is practical, pragmatic and is the law. With water we're in this together and the NPS underscores that.

Dialogue Contributions are welcome and should be 600-800 words. Send your submission to dialogue@nzherald.co.nz. Text may be edited and used in digital formats as well as on paper.

Ian Mackenzie is Federated Farmers' environment spokesman who was on the reference group for the National Objectives Framework.