1. If left to accidentally dry on glossy surfaces such as windows or shiny gutter or garage doors, TSP will cause permanent damage to the shiny surfaces and 'De-Gloss' paint or glass and stain metal and cement surfaces.
2. Use of TSP will give the possibility of violating the Clean Water Act or CWA. If evidence of pollution by TSP or other pollutant by your company's services cause a fish kill, waterway plant death, eutrophication of nearby bodies of fresh or salt water, you may be held liable. It is rare but can cost thousands in fines as warnings are almost never heard of. Many states only allow the sale of a TSP substitute. ( found at HOme Depot)