There is no limitation imposed by the spell itself as to what shape you can create the water in. So long as it is a volume that could contain the water so created (preventing creating compressed water), it validly satisfies the clause
Water can be created in an area as small as will actually contain the liquid
However, note that the range of the spell is "close (25 ft. + 5 ft./2 levels)", and any part of a spell effect beyond that distance from yourself is null and void per the usual rules for spell range. Therefore your 25' tall drain pipe is marginal for a 1st-level caster, depending on how far away from the bottom of the pipe they're standing and how high up the top of the water column is intended to be. The saving grace though is that (if I haven't erred in my calculations) a 4" diametre pipe of 25 feet length has a volume of about 65 gallons, which mightily exceeds anything a 1st-level caster could conjure anyway, making it easy enough to conjure its whole volume inside the spherical limitation imposed by the range.
So mind your ps and qs regarding range and your conversion of volume to linear feet of filled pipe, and you can pull off this use of the spell just fine.