The paper presents the recent challenges facing the scale, deposit, and corrosion control technology and some of the developments over the past decade to meet these challenges. All over the world environmental restrictions and cost cutting measures pose almost insurmountable challenges. More efficient cooling systems, such as high efficiency fill in cooling towers, higher reuse of cooling water to a point of zero blow-down, use of tertiary treated waters, higher pressure steam boilers, etc., are becoming industry standards. Use of heavy metals and phosphate for corrosion control is extremely restricted. Bio-dispersants are replacing biocides. Advances in the inhibitors which permit meeting challenges such as low phosphate, no-heavy-metal corrosion inhibitors, inhibitors which allow higher cycles of cooling water, halogen-resistant corrosion and scale inhibitors, surfactants as bio-dispersants, high-efficiency polymers, and the ability to accurately monitor chemical treatments are discussed in this paper.