Horizons Regional Council is seeking comment from various organisations about how well they think the One Plan is being implemented.
Letters have been sent to a range of groups including in the agricultural and environmental sectors, district councils and iwi, inviting them to respond.
It will be an ongoing evaluation which will first focus on nutrient management rules.
The One Plan, adopted in 2014, combined the regional council's policy statement, regional coastal plan and regional plan into one document and for the first time required intensive farming operations to have consent.
Horizons policy and strategy manager Tom Bowen said it had asked for feedback from organisations which would then be reported to council in August.
Mr Bowen said the council wanted to understand how groups thought the implementation was going and what required further attention.
"Depending on what the evaluation project finds we may make improvements to our approach to implementation of the plan, or council may decide to look at ways in which the plan itself could be improved," he said.
"It will not result directly in changes to the One Plan. At most it may identify that a plan change should be considered."
The Chronicle revealed this month that 40 per cent of farms which were required to lodge a resource consent by January 1 had not.
The council has also been granting discretionary consent for farms to leach nitrogen at up to three times the One Plan limit. But Horizons have put his down to changes on the Overseer model used to estimate nitrogen leaching.
Regardless of the feedback, Mr Bowen said Horizons would be required to make amendments to the One Plan over the next few years to incorporate aspects of the National Policy Statement for Freshwater Management 2014.