Raccoons may not be coming back so much as they have never left. A raccoon that is defecating regularly on your property lives in the area. Most raccoons limit their roaming to a hundred or so square meters and remain in one neighbourhood their whole lives. This is one reason why trapping can be deadly for a raccoon. I do not know how to live in another area, where to get food or where to find water or shelter. This is important because raccoons are protected wildlife and causing them to die by neglect in an area they do not know is illegal. The reality of the situation is this raccoon likely lives on one of your neighbour’s properties. They wander outside and need to go to the bathroom so they use your property instead of going back. Once they do this they have left a mark. This mark will lead them back to that spot naturally. They may not even know they are doing it or it could be very intentional as a way of keeping the feces separate from their nest. However, raccoon nests have been found to always contain feces so the raccoons may just be looking for a quick spot to go.
The best way to find out is to go to your neighbours and ask them if they have been hearing any strange noises or if they have checked their attic or under their deck or in their garden shed lately. You may just find the culprit like that and then can even help your neighbour hire a professional company to remove the animal humanely.
If this doesn’t work then you may have things on your property that are attracting the animals there. If this is the case then it won’t stop at raccoons, rats, mice, squirrels and skunks will also start showing up. Make sure your garbage cants are sealed. Test them, shake them push them over and see if the lid comes off. Give them a beating and see if they open. Rocks piled on the top are ok but they will fall off if the container is tipped. Bungee cords or a chain may do better but having a garbage can that has loops for a lock or one that has its built-in lock is much better. There are outdoor garbage cans that are specifically designed to stop wildlife from getting into them.
You will also want to make sure there is no access to food and water on your property. If you keep finding dead raccoons in your pool then this is why. Water is hard to find in dry months and raccoons cant just walk to a lake. They tend to rely, like all animals, on puddles after rains but if it’s been hot then they will come to your property for whatever wanter they can access. A pool, a leaky hose or even a birdbath. Remove anything from your property that could feed a raccoon and you will see far less of them.