According to the WRA, the six reservoirs are the Second Baoshan Reservoir, which provides water for Hsinchu Science Park, Yongheshan Reservoir, Mingde Reservoir, Liyutan Reservoir, Techi Reservoir and Zengwen Reservoir, which is the largest reservoir in the country.
As of 12 p.m. Monday, the water level at reservoirs in northern Taiwan -- Baoshan, Yongheshan, Mingde and Liyutan - were at 12.43, 11.81, 10.64 and 15.08 percent capacity, respectively.
Meanwhile, Techi and Zengwen reservoirs in Taichung and Chiayi were at 10.19 and 15.22 percent capacity, WRA statistics showed.
The water shortage can be attributed to the lack of typhoons last year, which resulted in the current problem, the agency said.
Tainan Mayor Huang Wei-che said on Monday he believes the city's reservoirs have sufficient water until July.
Tainan's Wushantou and Nanhua reservoirs are currently 49 and 47 percent full.
The city will not hesitate to drill wells for groundwater if the water shortage become a major problem for local residents, Huang said.
