Think about bottled water. One standard 53 foot trailer holds 30 pallets of the stuff. 58 pallets if they're double stacked. 30 pallets is about 28000 liters of water. I think I can buy one pallet with 1920 500ml bottles for about $380.00 right now.
I'm thinking it's still cheaper to ship fresh water.
I understand, however, you are comparing bottled water prices with tap water prices.
And comparing drinking-only water with all uses water.
Even these dry areas have quite enough drinking water. They need a lot more water for all other uses.
Comparing a semi-truck full of water with the water tanks that feed a city. There isn't any comparison.
Los Angles has several canals that are bigger than a semi constantly flowing water to the city. If you were to do that with supertankers, you would have to have a string of them, constantly delivering water. bow to stern as far as the eye could see.
Further, if LA could pay for that kind of shipping, Seattle has more than enough water. Much closer and already melted.
If they're dragging icebergs all that way just to flush down the toilet or pour down the drain, they're doing it wrong. Seawater works fine for that.
If you don't mind replacing the pipes every few years. ;)
I already pictured easily accessible above ground lines for that very reason. Something that could be swapped out, cleaned offsite, ready to be reused. If people want to live, they'll have to make changes. Look how many jobs I just created off the top my head...