What is DWV Pipe?
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Time to read 3 min
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If you've been in the market for PVC pipe and fittings you may have come across something called DWV. DWV parts look very similar to standard white schedule 40 PVC pipe and fittings. The only real difference is that DWV PVC is not made to handle pressurized uses like schedule 40 parts are. Instead, DWV pipe and fittings are made to handle a different class of uses – Drain, Waste, and Vent (hence the name DWV). Drain, waste, and vent applications use gravity to create the flow of water and waste through the pipe line. These applications cause minimal stress on the PVC parts, allowing for thinner walls and the elimination of pressure testing by the manufacturer.
How Do DWV Parts Differ from Standard PVC?
The result is a less expensive product with a few specialized parts that are particularly useful for drain and vent uses. A few parts that are typically used for DWV applications are p-traps, drains, and cleanouts. Another difference between DWV and standard PVC parts is the end types. Standard schedule 40 PVC fittings have ends that are either threaded or socket (sometimes called slip). DWV parts sometimes come threaded, but their slip style fitting ends are called “hubs,” and are usually shallower than the deeper schedule 40 ends. For example a slip coupling may be called “HUB x HUB” or “H x H” for short.
DWV parts are made with the same threading (NPT) and are made to the same size as standard PVC fittings. Since this is the case, DWV and schedule 40 and 80 pipe and fittings will fit together, but it isn't recommended that they be used together. Note: DWV parts should never be used to carry pressurized liquids or gas.
Looking for schedule 40 or DWV parts? Scroll over the fittings tab above to see all the parts we carry.
Designed for Gravity Flow: DWV stands for Drain, Waste, and Vent. These pipes and fittings are engineered strictly for non-pressurized systems, relying entirely on gravity to move water and waste.
Thinner Walls & No Pressure Testing: Because they do not need to withstand high-pressure fluids, DWV parts feature thinner walls and bypass manufacturer pressure testing, making them significantly lighter and less expensive than standard Schedule 40 PVC.
Shallow "Hub" Ends & Specialized Parts: DWV fittings use shallower slip connections called hubs (e.g., H x H) rather than deep sockets. They also include highly specialized plumbing shapes like p-traps, cleanouts, and drains that are not found in pressure-rated PVC lines.
FAQs
What does "DWV" actually stand for, and how is it used?
DWV stands for Drain, Waste, and Vent. Unlike standard piping networks that rely on force or pump-driven pressure, DWV systems use gravity to move water and waste entirely through the pipeline. Because they experience very low physical stress, these pipes are optimized for residential and commercial drainage and venting systems rather than fluid transport under high pressure.
Can I use DWV pipe and fittings in a pressurized water system?
No. DWV parts should never be used to carry pressurized liquids or gases. Because gravity-fed systems put minimal stress on the infrastructure, the manufacturer eliminates pressure testing and designs DWV parts with thinner walls. Using them in a pressurized application risks catastrophic failure.
Are DWV fittings compatible with standard Schedule 40 PVC pipes?
Technically, they will physically fit together because DWV parts use the same outer sizing and standard National Pipe Thread (NPT) specifications as standard PVC. However, mixing them is not recommended. Aside from the lack of a pressure rating, DWV slip-style fitting ends (called "hubs") are shallower than standard Schedule 40 socket ends, which can alter the integrity of the connection.
Mark Ligon
Mark Ligon is the marketing manager at PVC Fittings Online, a supplier of commercial PVC and CPVC pipe, fittings and valves. Ligon enjoys educating businesses on the parts of piping systems so managers can make informed decisions. He can be reached at webmaster@commercial-industrial-supply.com.
