After playing a couple days using the normal 5e rules for foraging – roll a survival check, if successful roll separately to see how much food and water you find – x 12 PCs and NPCs it became a pain. I ended up abstracting it by using the survival day rules from Dark Sun. Here is the modified rule:
Survival Days. A survival day is an abstract representation of the preparations a traveler must make to navigate the Underdark without risk of exposure. Each survival day includes water and food for 1 day and other basic necessities – like a pack to carry it in.
It also made it easier to say “the drow you just beat had a single survival day each” instead of tracking “they have 4 pints of water in a waterskin and 6 days of iron rations”. Survival days seem to be a good midpoint between the fiddly DMG rules and just hand-waiving the entire food/water situation away (which I think would be a mistake for the first half of the adventure).