The solubility of copper depends on what ionic form it is found in and what ions it is bonded with. Copper ionic salts are generally insoluble, although there are several notable exceptions such as halide salts and copper sulfate. Cu+2 is slightly more soluble than Cu+1.
The solubility of an ionic salt is dependent on the strength of the bond between the ions and the attractive force water has on the ions. The greater the force of attraction between the ions in the salt, the less soluble the salt is. The greater the effect of water on the ions in the ionic salt, the more soluble it is.