I am working on a project that needs a large collapsible water reservoir. I am thinking a kind of heavy duty plastic bag
kinda like this
I dont mind if its a wear part that gets replaced every few uses but it needs to hold at least 30-40 gallons of water without bursting easily for a couple days of sitting full (would not move around so sloshing not an issue).
any reccomendations as to a proper search term or a possible solution?
It would be supported around the top for filling/standing