Before

After

Cracked cast iron pipe

Cast iron pipes are prone to corrosion, particularly at the bottom where water tends to accumulate. This leads to a higher concentration of dissolved oxygen and corrosive compounds like hydrogen sulfide and carbon dioxide, which react with the iron to form rust. Over time, this corrosion weakens the pipe's structure, causing it to thin and eventually crack. When cast iron pipes crack or leak, they can cause significant water damage to the surrounding structures.