A storage developer wants to option my 6 acres. What am I looking at?

The option payment is a rental for taking your land off the market for two years, so judge it against what two years of holding costs you. Taxes, insurance, and the fact that you can't sell to anyone else in that window. $12,000 a year on a $310,000 parcel is roughly 3.9% annually. That's on the reasonable side of the deals I've seen, and the fact that it doesn't apply to the purchase price is what makes it reasonable rather than generous. If they wanted it credited toward the price I'd want double the payment.

Things to ask, in the order I'd ask them.

What happens to the entitlement work if they don't close. Get it in writing that any approvals, studies, surveys, geotech, and traffic work get assigned to you at no cost if they walk. That package is worth real money to the next buyer and they will resist giving it up. Some will agree to assign it for the cost they paid, which is still fine.

Second, extension rights. Most of these have one or two six month extensions at a higher payment. If they've hidden an extension that turns two years into three and a half, your land is tied up much longer than you think.

Third, the septic question is yours to answer, not theirs. A storage facility has almost no sewer demand, one office bathroom, so septic feasibility is probably a smaller obstacle for this use than for almost anything else you'd sell to. That cuts both ways. It means storage is a natural buyer for this parcel, and it means you should find out whether the parcel supports a use with real sewer demand before you accept a price set by the low-demand buyer.

On the $310k, get an appraisal or at minimum a broker opinion from someone who actually sells commercial land in that county. In a non-disclosure state you're paying for access to the numbers, and it's cheap relative to the decision. Have a real estate attorney in your state read the option agreement before you sign it.