Answer is: 250L of distilled water is 66,043 gallons (US) or 55,99 gallons (UK).
1 L = 0,264 gal (US).
250 L = 0,26 · 250 L = 66,043 gal.
1L = 0,223 gal (UK).
Gallon is a unit of measurement for liquid capacity in both the US customary units and the British imperial systems of measurement. The imperial gallon defined as 4,54609 litres (8 imperial pints) and US gallon defined as 231 cubic inches (8 US liquid pints) or about 3,785 litres.