If you are concerned call a local real estate agent see if they have the information on who owns it, if it is a bank etc. See if you can contact them regarding the matter, and if they have plans to clean the pool, or if they might accept you and or neighbors do some community help by cleaning up the house and pool. A win win situation as the bank that owns it has a easier time selling it, and you and the neighbors dont have a eye sore which can also bring your home values down. The bonus is that if someone was thinking of buying it, and notice that the community pitched in to clean it up, they will think of what a great neighborhood it must be. You might even put up a sign "Community keep it clean project" if the finance company allows it.