Product review (2 stars): Not 4 gallons as written on the box
2 stars because  it is not the capacity I thought it was as stated on the box. The box states it is a 4 gallon capacity it is only a 2 gallon capacity. It is misrepresentation. I am keeping it because of the function of  adding tap water instead of the expense of buying bottled water. Don't buy this if you want the 4 gallon capacity.