(Updated with information of the depth of the frozen soil wall holes, which is 30 meters)
The water was drawn from the lower permeable layer 20-meter deep, according to Kyodo News (6/24/2014) from an observation hole newly dug in preparation for monitoring the frozen soil impermeable wall that is to surround the reactor/turbine buildings of Reactors 1-4.
Cesium and all-beta (that includes strontium) are below detection levels, but tritium in 4-digit Bq per liter is apparently not what TEPCO has expected (or so they claim).
TEPCO's handout for the press on 6/24/2014 is about the observation hole No.H25J7 between the Reactor 3 turbine building and the Reactor 4 turbine building, whose water sample taken on June 10 was found with 140 Bq/L of tritium:
However, the handout also shows the test results for the sample water drawn from the observation holes for future monitoring of the frozen soil impermeable wall (whose construction has just started around the corner of the Reactor 1 building), Fz-4, Fz-5, and Fz-8.
The water sample drawn from the frozen soil wall observation hole Fz-5 between the Reactor 1 turbine building and the Reactor 2 turbine building on June 4 was found with 4,700 Bq/L of tritium (in red rectangle below):
TEPCO's simplified cross-section drawing:
English labels are by me, but I don't pretend that I understand what they mean by "groundwater pressure for the lower impermeable layer" (green line in the diagram).
Kyodo News says this will likely delay the construction of the frozen soil impermeable wall because an added work of preventing the spread of contamination is necessary when drilling holes for the frozen soil wall. The holes for the frozen soil wall are to be 30-meter deep.
The construction of frozen soil wall is already a challenge of dodging the underground structures (trenches, pipes, and other facilities) that TEPCO doesn't quite know about. No one apparently knows what's underneath the surface, after 40-plus years of plant operation and continuous construction and maintenance of the site. I suppose that problem would be the same whether it is Kajima's frozen soil wall or more traditional wall of sheet piles, as proposed by Kajima's competitors. (Not that it is any consolation.)
But this is hardly a piece of news, hardly anyone cares, as Japan's politicians, mainstream media and alternative media and social media are abuzz and obssessed with "sexist heckling" by a fifty-something LDP male politician in Tokyo Metropolitan Assembly against a 35-year-old assemblywoman whose former life was a pin-up girl for men's magazine and a minor TV "talento (talent, or personality)".