I forgot. I stumpled upon this geoscience site:

http://glorietageo.com/blogs/

I read thisone:
“Environmental Surveillance at Los Alamos during 2009” (pdf)

What I got from this was, that they hadn't had any contsmination of wells and that it depends on a lot of different factors, like the ground water flow direction, the shape of the landscape, the porosity/grain size. How hard you drill. I mean, if you drill manny holes at the same time and the pressure used, but it's in english, so you could get more from it and maybe tell if it's of any use to us.