The Northland Regional Council has imposed a catchment-wide water shortage direction for the entire Awanui River catchment.
The direction impacts on those who have consents to take water from the river, and those who can normally take smaller quantities of water without consents.
"In other words, we're restricting water to essential use only," water and waste monitoring manager Ali McHugh said.
"This includes people who have resource consents to take water for irrigation from the river."
Most consents for taking water from rivers had a condition that required water takes to stop once the rivers reached a specific (low) flow, and the Awanui River had undoubtedly reached that point, she said.
A large number of properties (within the purple boundary on the map) would potentially be affected by the catchment shutdown, which Ms McHugh said was the forerunner of similar directions for other Northland catchments with critically low river flows and groundwater levels.
The directive restricts water use from both surface and groundwater sources to "reasonable household and stock welfare needs". Water cannot be taken for irrigation, garden watering (other than with recycled domestic grey water) during the direction's 14-day term. Car washing, water blasting and filling swimming and spa pools are also banned.
"We will review the situation after the 14 days is up, and it's likely that further directions will be issued if no significant rain has fallen in the catchment," Ms McHugh added.
"We will monitor water use, and those found using non-essential water may find themselves facing enforcement action."
Anyone who had a critical need to take water, and was unclear about whether or not they could continue to do so under the water shortage direction, was advised to contact the regional council on (09) 470-200.
Ms McHugh noted the council had been issuing general advice about dry weather and low rainfall, and warning of potential water shortages, since spring, and had begun formally advising consent holders late last year.