I've played stranded 2 survival list for a while.I built 4 wells on different places on my island but it said ''you didn't find water''.so my wells are empty. i tried to build a 5th well and it worked.''you've found water''. i just want to know is there any way to find water to build a well.

why not ask in the thread for that mod?
TheSurvivalist:Christmas Update 12-24-19

also a "survirvalist" is not a "survival list" but a person who survives

no, if you dug a dry well they fill up with water when it rains. At skill level you can prospect for underground springs with your shovel...once found you can build a pump on them.

or crush 15 vines with a rock...or 30 leaves...if you have a bottle.