Keurig Model 870 Water Leak - Overflow Solution!
We have a model 870, and here is what we have discovered to solve the occassional water leaking and overflowproblem. When you first drop a new "K" cup into place, push it down tight with your fingers so that it sits tight into place and you feel the bottom of the K cup get punctured. Doing this manually ensures that the bottom of the new K cup gets pierced adequately. The foil on the top of the K cups are easy for the coffee maker to pierce consistently but the bottom plastic is tougher and more rigid which results in periodic K cup/pod puncture failure. The reason this occurs is because when you pull the handle down before brewing, there is a gap spacing and it doesnt press the K-cup all the way down to get punctured properly on the bottom and so the water runs into the K cup but not all of it can run out the bottom, hence the overflow. Hope this helps.