‘I own a property that has always used water well and septic system from a joining property. Do I have an automatic easement?’
Maybe. The concept you’re looking for is called a “prescriptive easement,” and the specific rules vary from state to state. The outline, however, goes like this: if you use another person’s land, openly and continuously and without permission for the requisite amount of time, you then have an enforceable right to continue that use.
The most likely stumbling blocks in your case are the length of time and the issue of permission. Each state has a specified length of time, and those lengths vary widely, so you’ll need to find out whether your
situation meets the requirement in your state.
Second, if the neighbor who owns the land with the well has given permission for you to use it, that permission can be revoked no matter how long it has gone on.
But if all the elements of a prescriptive easement apply to your situation, then yes, you may have one. Be aware, however, that proving this right can often be a difficult and expensive process. Depending on who your neighbor is, you may be better off negotiating with them for an express written easement, even if you theoretically already have one.