A little hard to understand what you wrote in OP, appears as though you have a continuous grounding electrode conductor from service to building steel. Presuming building steel is a qualifying electrode, that alone is all you need to run the GEC to. You can then run bonding jumpers to water pipe from building steel and/or to any ground rods. BTW if you have building steel and water pipe electrodes those must both be used, but there is no NEC requirement to add additional rods in that situation. If you had water pipe only - it must have a supplemental electrode - rods are typically chosen for this because they are simplest and least cost, not because they are absolutely required.