Environment Southland is monitoring all rivers and aquifers in the region following the dry spell of recent weeks.
Director of science and information Graham Sevicke-Jones said the region had not experienced a dry spell like this since 1990.
''The river that is lowest compared to normal is the Aparima River. The levels it is at typically only occur once every four years on average, but usually further into summer.''
Rainfall for the region was at 79% of normal and in some areas even less, he said.
''Central Plains has only received 61% of the normal annual rainfall. Otahuti has received only 63%. October was the driest we have on record, with the region only receiving 40% of the normal October rainfall.
''The upper Aparima catchment only received 12% of the normal October rainfall. The upper Mataura, Oreti and Whitestone were also very dry.''
All of this had contributed to low aquifer levels.
Half the groundwater sites Environment Southland monitored showed the lowest levels recorded for this time of year, spread right across the region from Edendale and Isla Bank, through the Waimea Plains (Riversdale, Waipounamu) and right up to Nokomai.
''None are yet at all time lows
but it's still early in the summer. Areas with particularly low groundwater levels are Edendale, Wendonside and North Range aquifer in the Mossburn area,''
Mr Sevicke-Jones said.
The dry weather had also prompted warnings from Fire and Emergency New Zealand (Fenz).
The year was shaping up to be much drier than previous years and with the La Nina conditions forecast, it was only going to get hotter and drier, Fenz rural operations national manager John Rasmussen said.
''This means greater a greater risk to life and property. With many areas going into restricted fire seasons, people need to take action now.''
Data showed current soil conditions were drier than normal and DairyNZ was encouraging farmers to be prepared.
DairyNZ extension general manager Andrew Reid said farmers always factored variable weather into their seasonal plans, so many would be well prepared.
''However, it is timely to revisit the summer plan and talk through different scenarios with the farm team. For example, supplementary feed usage, culling policies, once-a-day milking, irrigation priorities and what the target dates and trigger points for dry-off decisions are.''
In Otago, farmers were already taking action, with upper Taieri farmers instigating a voluntary water roster as the Taieri River drops near its minimum flow at Waipiata.
The Otago Regional Council was continuing to monitor river levels in the region closely, as many were at low levels.
Director of environmental monitoring and operations Scott MacLean praised water users in the upper Taieri.
''This is an excellent example of the community working together for the benefit of the river.''