The answer depends on 13 WHAT!
3.25 qts
That is 3 gallons and 1 qt.
13 Qts. give or take
13 gallons = 208 cups1 gallon = 4 qts = 16 cups13 x 16 = 208 cups
3.25 qts
1.5 qts 1.5 qts 1.5 qts
13 qts 1 quart = 2 pints 1 pint = 0.5 quart
If completely empty it will hold between 12 and 13 qts.
6 gal = 24 qts
13 quarts is equal to 26 pints. Each quart contains 2 pints.
4.5 qts (5 qts when filter is changed)
If totally empty it takes between 12 to 13 qts.