Thirst and dehydration in Die2Nite

If you don't drink every day you become thirsty, if you walk for long in the desert, too. But how exactly does dehydration work?

I'm mainly interested in the corner cases.

• Is the thirst from not drinking a day cumulative with walking in the desert? So if I start the day thirsty and then walk 10 steps in the desert do I get dehydrated?
• Is the number of steps you can take outside before getting thirsty for one trip and it gets reset if you're in town or is it per day?

The answer to the first one is yes. You'll get dehydrated if you're already thirsty and you walk 11 steps, or if you walk 22 steps.

The second one is per day. If you walk six steps, enter town, and walk six more you'll be thirsty at the end. I have experienced this one personally.