Your method of grounding will be code compliant.If you decide to use the metal underground water pipe for your electrode,250.52(A)(1)says there must be 10 feet or more of metal water pipe in direct contact with the earth. You must supplement the metal water pipe with an additional electrode specified in 250.52(A)(2) thru (A)(7), according to 250.53(D)(2)
If you select a rod,pipe,or plate eletrode then you must comply with 250.56 which states that you need 25 ohms or less or add a 2nd electrode.
You do not need 4 electrodes for one service drop to a building.See exsample exhibit 250.28 on page 201 of the 2002 NEC handbook.Although the exhibit is misleading in the picture as it shows the #2 GEC just ending without terminating at the service equipments grounded conductor as required by 250.24(A)(1)
shortcircuit
