(Source) http://fukushima-diary.com/2013/08/tepcos-data-shows-600-tones-of-groundwater-flows-to-the-sea-everyday/

On 8/7/2013, the Agency of Natural Resources and Energy admitted 300 tones of groundwater flows to the Pacific everyday.
(cf, [Breaking] JP Gov admitted 300 tones of contaminated water flows to the Pacific every single day [URL])
On 8/9/2013, Tepco released the report that they submitted to the Agency of Natural Resources and Energy.
The report shows the total volume of groundwater to flow into the plant is 1,000 tones / day. 600 tones are flowing to the Pacific.
There is a possibility that the Agency of Natural Resources and Energy declared only half of the actual estimate as the volume of groundwater to flow into the Pacific.