Control of microbial re-growth on iron pipes is a major challenge for water utilities. This work examines the inter-relationship between iron corrosion and bacterial re-growth, with a special focus on the potential of iron pipe to serve as a source of phosphorus. Under some circumstances corroding iron and steel may produce all key nutrients necessary for bacterial re-growth including fixed carbon, fixed nitrogen and phosphorus. Conceptual models were examined to compare the relative importance of phosphorus derived from bulk water versus that coming from corrosion. It seems clear that phosphorus from corroding metal could serve to remove limitations to re-growth that might exist in the bulk water. Includes 32 references, figures, appendix.