I would like to know how do I customize the water in SAP when this is a part of the product, but the cost is nearly zero. How do I do to not cost it and not count it's inventory?
If you want to see the qty and costing of a material, include it in the bill, with the costing relevancy indicator ON.
If you want to see the qty, but no costing, include it in the BOM, but set the costing relevancy indicator off.
If you don't want to see the qty or the cost, remove the material from the BOM.