Akhtar Mohammad Nosrat said as per the agreement, under normal circumstances, Iran receives 22 cubic meters of water per second.
He added as a good neighborliness jesture, 4 cubic meters per second will also be added to the mentioned figure.
Mohammad Nosrat said that this practice will continue but in the event of a drought, Iran will receive less water from Helmand River.
Iranian President Ebrahim Raisi recently said the Islamic Republic will not relinquish its right to the water from Helmand.
Following the statement, Foreign Minister Hossein Amirabdollahian spoke with his Afghan counterpart Amir Khan Motaqqi.
Amirabdollahian expressed hope that the Taliban would remove artificial obstacles in the way of water flowing toward Iran.
He warned the Taliban that cooperation between the two sides would be adversely affected if this problem was not resolved.
Tehran has on several occasions said the the Taliban have violated the 1972 agreement. The Taliban deny this.