Farmers in some regions are already well into the changing world of environmental regulation.
Under the Government's National Policy Statement on Freshwater, all regional councils are required to consult with stakeholders, come up with new rules for freshwater management and set limits on levels of nutrients allowed in waterways.
In Manawatu, Horizons' One Plan is already in force, following years of Environment and High Court battles over its scope, and Environment Canterbury's Land and Water Regional Plan will likely become operative before the end of this year. And farmers around Lake Taupo now have to meet strict new rules on nitrogen leaching.
"It all comes down to where the limits get set and what the expectations are of the community around the absolute state of water quality," says DairyNZ environment policy manager Dr Mike Scarsbrook.
"So if there are very high expectations in terms of improving water quality from its current state, then there're going to have to be some major changes in land management and possibly even land use in a catchment - and that comes at a significant cost.
"If the expectations of the community are more around protecting current water quality, then the changes required on-farm may be no more than we'd usually do as we move toward good practice or improving efficiency of resource use."
The National Policy Statement on Freshwater is a response to declining water quality in streams, rivers and lakes in both rural and urban New Zealand. Much of the decline in rural areas is blamed on the rapid expansion of dairy farming but all agriculture will be affected by the new rules.
Under the statement, councils are expected to maintain or improve water quality, safeguard freshwater ecosystems and indigenous species and set objectives for all freshwater bodies. The proposed amendments will bring in more specific rules and establish what's called a National Objectives Framework.
The first step for each region is be to bring together all stakeholders - including farming, industry, recreational, iwi and environmental - get them to establish agreed values and then work through a process of setting limits and designing a management plan.
This plan will be formally drawn up by council planners, put out for consultation and submissions, go through an appeals process and eventually become law.
Manawatu is further through the process than the rest of New Zealand with the One Plan being completed before the NPS was formulated.
Nutrient limits in the original plan caused bitter division between council and farming interests and millions of dollars were spend on court action.
With a modified plan now in force, some of that bitterness has eased and farmers in two small catchments are now working on implementing the new rules.
The council is now taking a pragmatic approach, says Federated Farmers water policy advisor Paul Le Miere.
"There's definitely a change of mentality that they want to get people through this and get the pathway in the right direction, rather than be dogmatic around the numbers and definitely not hit people on their profitability adversely hard."
One Plan will need modification further down the track to make it comply with the NPS, but that's likely to be matters of detail rather than a change in the overall thrust of the plan.
In Canterbury, the new Land and Water Regional Plan has been notified and is now under appeal on points of law. It is generally expected to be operational later this year.
The region has been broken into 10 zones corresponding to different catchments, and committees have come up with plans for the zones. Nutrient limits have been set in some zones while others are working through this process.
For some farmers, the LWRP is likely to cause real pain, depending largely on where their farm is and what sort of land it's on. In "red zones", with "leaky" stony soils and degraded waterways, they will face challenging N-loss limits.
"If catchments are deemed to be over-allocated, say around nutrient levels and particularly around nitrogen, then there's going to have to be some significant changes in that catchment on-farm to address that over-allocation," says Scarsbrook.
If farmers can't meet their N targets, some tough decisions await them. "That becomes a very difficult conversation because once the limit has been set, you move into a question of how to allocate that slice of the pie."
Meanwhile, work has started on the giant Central Plains Water project that will eventually water 60,000ha of Canterbury farmland between the Rakaia and Waimakariri Rivers.
Government agency Crown Irrigation Investments confirmed last week it would lend Central Plains Water $6.5 million to help pay for the $140m stage one of the scheme.
DairyNZ is working with farmers everywhere to improve management and make the most efficient use of all their resources but there's only so much can be done.