The Government has released draft water quality guidelines which will set bottom lines for rivers, lakes and other freshwater bodies across the country.
Environment Minister Amy Adams said the "National Objectives Framework" for water quality would help communities and local authorities set freshwater objectives.
"The innovative thing about the proposed national objectives framework is that it provides regions with both a process, and a scientifically-informed basis for the difficult conversations that communities are already having on water quality.
"Scientific information is critical to the conversation about managing our water, but it cannot resolve conflicts over values. Nor can it decide what trade-offs or choices are worth making; or who bears the costs or should benefit from these decisions.
"Although we might agree that clean water is important, there are many different views about what this actually means and on how we can achieve the water quality for the uses we want.
"There are also many different views on how much risk we are willing to tolerate, and what we are willing to sacrifice when we make choices about how we will use our water."
Ms Adams said those discussions were very difficult ones for communities, "and we all have stories about how hopeless or frustrating they can be, as many end up with continual and costly debate in the Environment Court".
"The proposed framework provides a process for working through these issues - as well as numeric values for some of the water quality attributes we need to manage.
"The proposed amendments provide compulsory national values with national bottom lines for ecosystem and human health for activities such boating and wading."
Ms Adams said she expected the proposed bottom lines would be debated, but once agreed, "the framework will reduce the arguments in council and in court over the science behind regional plans and resource consents".
The objectives which set limits for pollutants such as nitrates, phosphates and also levels of algae had been developed by more than 60 freshwater scientists, across public, private, and academic sectors.
"The scientists have worked to ensure that these numbers are robust. Ministers have not involved themselves with the scientific detail of the framework."
The numbers have also been tested through a reference group of water users including primary sector representatives, regional councils and recreational groups.
"We now want the views of the wider public."
The objectives are contained in a discussion document which also proposes explicit consideration of tangata whenua values for freshwater.
It also proposes local authorities better measure water use and discharges into waterbodies in their regions and what is discharged into water bodies, information that was crucial for setting effective freshwater objectives and limits.
Government's proposals for fresh water management
a national framework to support communities setting freshwater objectives
explicit recognition of tangata whenua values for freshwater
ecosystem and human health as compulsory values in regional plans
bottom lines for ecosystem and human health that apply everywhere, and
restricted grounds for exceptions to bottom lines; and
requiring councils to account for all water takes and contaminant discharges