看铜管上的颜色， 如果你当时注意的话

Copper pipes are categorized primarily by wall thickness—Type K (thickest), Type L (medium), Type M (thin), and DWV (drain-waste-vent)—with color-coded markings (Green: K, Blue: L, Red: M) indicating their, durability, and pressure ratings

. Type K is used for underground/heavy-duty, Type L for interior plumbing/HVAC, and Type M for residential water supply

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