My water meter is identical to those installed on a house (I bought it
from a couple of city water contractors in Littlefield, TX) and seems
to be very accurate based on the scales at U.S. nationals. I also
plumbed it in line with one of the plastic meters this summer at Hobbs
with good agreement.

I formerly used 5 gal. water cans but got tired of hauling them
around, lifting them in and out of the van, pouring from them, etc.
Years later, I went to a homemade tire innertube carrier similar to
P3's. If I kept it in a cartop luggage carrier like he does, I might
still use it but mine rolled off the roof turning into my assembly
area one morning. It was comical getting enough people to sit on it to
create sufficient pressure to get water through the hose. Finally,
after we'd partially emptied it, the ungainly thing was light enough
for a bunch of us to lift it into the bed of someone's pickup truck so
I could finish filling. This one developed cracks over the years,
probably from the UV exposure, as did the one I replace it with.

More recently I just hook up to spigot with a long garden hose, a
standpipe (to limit pressure), the aforementioned water meter, and a
hose plugged into the main dump port of the glider (which connects to
both tanks). It's very simple to fill any amount up to maximum
allowable so long as I can get the glider to the spigot.

Chip Bearden
ASW 24 "JB"
USA