You may want to take the time to inform the current owners of that in person. If the house is not currently occupied, have a title company research the ownership and then reach out to whomever owns it. You could also contact a local Realtor and have them establish a search in the MLS in case that address is ever listed for sale, they could then let you know right away.
Finally, if you wanted a more formal arrangement and can make contact with the current owners, you could work with a local realtor to establish a purchase option for you. Essentially you would sign a contract and give the owners a small amount of money now so that you would have the right to be the first person to purchase the home when it does come for sale. Good luck!!
Keller Williams Premier Realty