What components make up a grounding electrode system?

A grounding electrode system per NEC Article 250 typically includes: metal underground water pipe (first 10 feet), building steel frame if effectively grounded, concrete-encased electrode (Ufer ground) in footings, ground ring around building, rod or pipe electrodes, and plate electrodes. Multiple electrodes must be bonded together. Resistance should be 25 ohms or less; if not, additional electrodes are required. Supplemental electrodes may include ground rods or chemical grounds.