Dan, do you really need FIVE giant sized water bottles?
In a word..."yes".
They provide 6.5l capacity on the bike and for desert travel, I add *two* 10l MSR Dromedary bladders for a total capacity of 26.5l. Much of the water where I travel in the Great Basin is alkali and undrinkable, so I pack water in with me. At ~1kg/liter + container, this means a bit more than 26.5kg/58.4lbs in water alone...showing why I sometimes really need the Nomad's greater cargo capacity.
I use pH strips to pre-test any water I do find to see if it is even worth purifying it. I am most likely to get water from stock tanks, cattle troughs, and seep-pools, but it is often contaminated by cattle urine and feces so I zap it with my SteriPen, chemical tabs (iodine or chlorine), or boil it. Usually, the SteriPen wins because it is quickest, purifying 1l in just 90 seconds. You can see water is a problem noted on the visitor board for Nevada's Black Rock Desert, which I have crossed a number of times in Spring, Fall, and high Summer.
When it is hot I consume about 8-8.5l/day, as I did on both my transits of Serbia during heat waves. It was incredibly warm with no real shade or cover throughout the day. It was 114F°/45°C by 10:30am and very humid. It can be that warm and hotter in the desert, but with very low humidity.
If I have a "dry" camp (one without access to a stream or other water I can purify), I also need water to reconstitute my food for meals. Between supper and breakfast, this can easily total 9l/day combined for fluid intake and eating.
This means 26.5l provides just shy of three days' water for my needs, not a lot of margin if I get hurt or incapacitated while traveling alone in remote backcountry.
Are they for the patented travelling shower ?
No...I have a shower attachment for the MSR Dromedary bags!
All the best,
Dan.