There will also be a focus on at-risk catchments to halt the decline – "we're not going to leave the hard issues for future generations", Parker said.
The Resource Management Act (RMA) will also be amended within 12 months to enable regional councils to more quickly implement water quality and quantity limits.
"Clean water is our birthright. Local rivers and lakes should be clean enough for our children to swim in and put their head under without getting crook."
The work programme also sets out a new approach to the Māori/Crown relationship that will acknowledge Māori interests in fair access to water to develop their land.
"We are committed to a substantive discussion on how to address Māori interests, by taking practical steps to address constraints on Māori land development," Davis said.
Asked if the five-year target was a lofty goal, Parker said he was "confident within five years we will be seeing measurable progress".
O'Connor said there had been some disagreement between the Government and agricultural groups around the speed of travel.
He said farmers are already "ramping up their game", in terms of contributing to better water quality, but farmers have been doing as much as they can as quickly as they can.
The measurements have been "confusing at times", he said.
But Federated Farmers water-quality spokesman Chris Allen said the five-year goal, set by Parker, is "really ambitious".
He said in the past 10 years, farmers have come "a huge way" when it comes to water quality and the pace of work has been increasing.
Irrigation NZ chairwoman Nicky Hyslop said she supported the overall intent of the plan, but wanted to see policy certainty sooner than 2020.
"There are some concerns around whether there will be more changes around current regulations that will mean some of the exciting technology being invested in now to improve environment footprints may be made redundant."
National's Environment spokesman Scott Simpson said today's announcement was underwhelming.
"Today's announcement is just another working group that kicks water issues to touch until 2020. Although it is concerning that 'coincidentally' this is when the Government's Tax Working Group proposals of a series of new environmental taxes would take effect."
He said farmers and growers would be concerned Labour's water tax was back on the agenda alongside a whole suite of proposed environmental taxes.
Green's Co-Leader Marama Davidson said her party was "rapt" by today's announcement, saying it was a major win.
"This is something that the Greens have been working on for all of our existence as a party and we're really proud of the influence to make sure we clean up our rivers."
Parker said the Government would work with a range of vested interests in establishing its water plan, including environmental NGOs, Māori, farming leaders, scientists and regional council experts.
He said the Government was already working with the primary sector and regional councils in the most at-risk catchments.
O'Connor said the primary sector was crucial to having an environmentally sustainable, high-value economy – "this is why we must grow a sustainable and productive primary sector within environmental limits".
