 If these pits form, failure times can be expected between 6 months and 2 years from initiation.The mechanism that leads to the pitting of copper in cold hard waters is complex, it requires a water with a specific chemistry that is capable of supporting pit growth and a mechanism for the initiation of the pits.The pits that penetrate the bore are usually covered in a hard pale green nodule of copper sulfate and copper hydroxide salts.