1 ENC is about 3 kg (if water this is 3 liters). This means that 1/2 ENC is 1,5 kg and 1/4 ENC is 0,75 kg. This means that, 1/2 ENC of water is 1,5 liters and 1/4 ENC of fuel is 1 liter since fuel (gasoline(diesel) is roughly 0,7-0,85 kg per liter.Is 1/4 for a liter of fuel? That's about half what it should weigh.The Official Foundry T2K module lists
Clean Water Wt 1/2 Pr 1 (this is a new entry in the list).
Diesel/Gasoline Wt 1/4 Pr 50 (the weight is new).
EDIT: That is, of course, assuming that water is also rounded to 1 liter rather than the 1/2 ENC of a day's ration. 25 kg or 8 ENC is still a good number for a jerrycan and that supports 1/2 ENC for a liter of packaged fuel.
Sure, ENC is also bulk, but for liquids that is carried in containers, that is not an issue. The ENC for other items may have to be adjusted because of their shape and form.