Without special clothing (desert clothing) you need to take a drink every 90 seconds. With a full set of desert clothing, one drink every 120 seconds; so a full waterskin will last 6-8 minutes.
A better alternative is an enchanted water tiara (it has quest requirements), which is practically unlimited: each "drink" reduces it by one charge, one charge requires 3 water runes, and you can add as many charges as you want.
a few minutes.
1 MONTH FOR CHEAPEST
I can't find specific information, but it will be much less than combat with most monsters. Normally you should have time enough to get to safety. On the other hand, your health will gradually go down, so better take enough waterskins with you. Those will last much longer than food.
they can last anything from 1-3 Minutes before one by one they go out.
It depends how long you are on Runescape.
it only helps to have waterskins
Waterskins. Waterskins can be bought from Shantay, who is located in Shantay's Pass. They slowly dry out over time. consequently, it is often advised that one purchases a surplus prior to going into the desert.
You can purchase desert robes and waterskins before entering the desert, and that usually keeps you cool and not thirsty making you completely safe to roam.
6 minutes
a few minutes.
1 MONTH FOR CHEAPEST
its PERMANENT!....forever...
I can't find specific information, but it will be much less than combat with most monsters. Normally you should have time enough to get to safety. On the other hand, your health will gradually go down, so better take enough waterskins with you. Those will last much longer than food.
they can last anything from 1-3 Minutes before one by one they go out.
It lasts exactly 4 minutes and 32 seconds. i counted =P
There are 32 rocks of sandstone in the western desert mining site. This is south of the bandit camp in the Kharidian Desert and on the runescape map will be labeled as "Quarry". If you want to mine there though you should where desert robes and bring waterskins so you do not lose health due to the heat. Also you will need a shantay pass in order to enter the desert which can be bought at the entrance for a small fee.
I believe an anti fire pot lasts either 5 or 6 minuets.