I wish all fuel tanks had a low spot, or "sump" for the water & alky to settle into, along with a petcock to allow easy draining of the stuff! Having the fuel valve in the bottom of the "main floor" of the tank, above this sump.
Yeah, that would be a good idea.
I know that light aircraft all have a setup like that.
Back when I owned a Cessna 140, part of the preflight inspection included opening each petcock (it had a tank in each wing) and draining a bit of fuel to check for water.
The other 'cardinal rule' was that you always fueled up AFTER each flight to minimize condensation.