Legal Question in Construction Law in California

There would be an implied warranty that the construction, components, etc. were of at least passable quality at the time of installation, and perhaps you received an express (written) warranty as well. However, some rust spots after eight years is not necessarily evidence of defective materials or workmanship, and before pursuing a claim you should probably consult an expert to get an opinion as to whether the workmanship and materials clearly are and were below standard in the pool buainess.