If you build a fence and/or any other structures, be prepared to have to move them. Also, if you ever sell your house, it would be nice to inform the new owners.
We have some friends whose house backs up to a canyon (I think it’s San Diego City property). When they bought the house, they just assumed the fence was put on the property line. They’ve lived there for a few years, never did anything with that part of the yard (just native plants I think). Recently, they decided to put grass and put up a swing set near the fence. When the city saw that, they then had a problem with the fence being on public land and were going to fine them $500 a day until the fence was put on their property.
