We find that the cast-iron pipe is only mildly corrosive and the indoor pipeline is just rust-eaten, but the seamless steel pipe corrodes badly.

• 结果表明：主干线灰口铸铁管整体状况良好，只有局部轻度腐蚀；庭院无缝钢管腐蚀较严重；户内管道大多存在不同程度的锈蚀。