Copper DWV pipe

Entry in Metal pipe · Updated October 29, 2026 · Written by the Know Your Pipes editors from the sources listed under References

Copper DWV pipe is hard-drawn copper drainage tube made to ASTM B306 for drain, waste and vent (DWV) piping, and it is identified by a yellow print line^[1][2]. It is a separate product from the K, L and M water tube made to ASTM B88, although the copper alloy is the same^[1].

1 Identification and sizes

Makers sell DWV tube only in the hard temper, in 10 ft and 20 ft straight lengths, with a yellow color code^[2]. One maker lists DWV tube from 1-1/4 in through 8 in nominal size^[1]. Each length is also incised and color coded, so the type can be read even where the ink has faded^[3].

Within a house drainage system the tube can form stacks, branch drains and vent lines. Other materials serve the same purposes, including cast iron drain pipe, PVC DWV and foam core and ABS pipe.

Table sources: one maker's product table^[2] and its alloy statement^[1].

2 Use and limits

Makers describe DWV tube for drainage, waste, vents, soil lines and other applications that do not run under pressure^[2]. The drinking-water certification to NSF/ANSI/CAN 61 that makers cite is stated for types K, L and M, not for DWV tube^[1]. One maker's data sheet does give calculated working pressures for annealed DWV tube, such as 135 psig at 150°F for 3 in tube, as engineering data rather than a listing for pressure service^[1].

Drain fittings differ from pressure fittings: a sanitary tee or wye has a swept, gradual turn so waste flows in the right direction. Copper DWV tube can be joined with solder-type fittings, as described under soldered sweat joints, and a connection to plastic or cast iron needs a listed transition fitting. Which drain materials are allowed is set by the local plumbing code.