82:11 If a channel of water runs through a courtyard, one may not draw water from it on Shabbos. (This only refers to a stream that is ten handbreadths deep and four handbreadths wide; smaller than that is not problematic – Mishnah Brurah 356:2.)
82:12 One may not stand in a private domain and urinate or spit into a public domain or a carmelis, nor from a public domain or a carmelis to a private domain, nor from a public domain to a carmelis or vice versa. (This is true even if he extends his mouth or any other necessary organ into the other domain – OC 350:2. Likewise, one may not spit or urinate a distance of four cubits within a public domain or a carmelis – Mishnah Brurah 350:10.) Similarly, one may not walk four cubits in a public domain or a carmelis, or from one domain to another, with saliva in his mouth. This refers to saliva that is already in his mouth and ready to be expelled.