For the sake of filling in the answer box,
it depends utterly on your local government.
this varies drastically across the US,
and even within one municipality, depends greatly on other factors, whether it's a division, zoning, etc
Your supplementary questions about fencing etc: exactly the same applies.
Pick up the phone and call the local council/whatever.
FOOTNOTE: when one hears about someone "wanting to buy a gold coin!", in 50% of cases they are about to be mildly-to-middlingly ripped-off by some idiot selling gold coins at a horrible price using local TV ads featuring photos of Mt Rushmore, etc. Similarly, when one hears about someone "wanting to buy some land!" there is a chance that essentially, you're about to be ripped-off by some idiot with TV ads and a homegoods MLM scheme on the side. So, take care.
Few things in the world can be smarter than a land bank.
Few things in the world can be dumber than a land bank.
Your other question,
"Will a lack of sewer/septic reduce the possible investment value in the future or is that for the next owner to worry about?'
Yes, IN SOME CASES, if you do the work of adding utilities, that will HUGELY increase the value of the piece of land.
In OTHER cases, it will achieve utterly nothing / likely be a total waste of money.
It's impossible to answer without knowing every fact, location, land type, etc etc; even then local experts would disagree.
Another good trick is, you are surely using an agent. The agent will give you GREAT and local advice on all these issues. (Unless you are being ripped-off so badly that even your agent is in on it. :/ )
Always ask your agent everything. If you don't have an agent, just call every local agent and they will freely and generously give you completely free really useful advice.