What is the difference between ABS and PVC pipe?

ABS (acrylonitrile butadiene styrene) is black and tough. PVC (polyvinyl chloride) is white or cream and stiffer. Charlotte Pipe, a large U.S. maker of both, publishes the numbers side by side, and they explain most of what you see on a job site.

Two rows matter most in daily life. The impact number says ABS shrugs off a dropped tool or a shovel in the trench better than PVC does. The expansion number says ABS grows about twice as much as PVC when it heats up. Run 50 feet of pipe through a 60 degree swing and ABS lengthens roughly 2 inches, PVC roughly 1. That is arithmetic from Charlotte's table, and it is why long runs need offsets or support that lets the pipe move. Our page on pipe hanger and support spacing covers the rest.

Both systems are made for drain, waste and vent work only, at temperatures up to 140 degrees Fahrenheit. Charlotte's foam core ABS page says it is for "nonpressure systems where temperatures will not exceed 140 F." The PVC DWV submittal says the same for PVC. Pressure-testing either one with compressed air is a safety hazard, so DWV lines are tested with water.

### What are the standards, and what is cellular core?

The ASTM numbers on the pipe wall tell you what you have. ASTM D2661 covers ABS drain, waste and vent pipe and fittings. ASTM D2665 covers the PVC version, and ASTM D1785 is the general Schedule 40 PVC pipe standard, so you will often see both PVC numbers printed together.

Cellular core (foam core) pipe has a foamed middle layer between solid inner and outer skins. It is made for DWV only. The ICC's 2024 International Plumbing Code lists ABS and PVC pipe in "solid, cellular core or composite wall" form. Separate ASTM standards cover the cellular versions, F628 for ABS and F891 for PVC. Never use foam core pipe for anything under pressure.

The cement is the biggest practical difference. ABS joints take a single coat of ABS cement, made to ASTM D2235. Charlotte's ABS page says its pipe is "easily installed by solvent cementing (no primer required)." PVC is a two-step joint: a primer made to ASTM F656, then cement made to ASTM D2564. In the code, the PVC primer is purple, and the cement cannot be purple, which makes a skipped step easy to spot.

Do not use ABS cement on PVC or the reverse. To join the two plastics you need transition cement, made to ASTM D3138. That standard is narrow on purpose. It says these cements are for "non-pressure applications only" and gives the typical use as joining an ABS building drain to a PVC sewer. It adds: "Specific cements for ABS or PVC components should be used." Oatey sells a green transition cement for exactly this, for non-pressure joints up to 6 inches.

Code limits it further. Section 705.16.4 of the ICC's 2024 code allows a solvent-cement joint between different plastics "only where a single joint is made between ABS and PVC pipes at the end of a building drainage pipe and the beginning of a building sewer pipe" and requires the D3138 cement there. Anywhere else, the joint has to be a listed adapter or a mechanical coupling. So a mixed-plastic patch inside a wall is not what the code has in mind. Use a proper adapter or a rubber shielded coupling made for the job, and have the work inspected if it needs a permit.

Neither is meant to sit bare in the sun. Charlotte's technical article says UV "affects ABS, CPVC, and PVC" alike, and that the damage is limited to a very thin layer, "0.001 to 0.003 inches." Over time, PVC tends to yellow or brown and ABS tends to fade or bleach. The same article says: "The most common method used to protect aboveground ABS, CPVC, and PVC pipe from the sun is painting it with a latex (water-based) paint."

In a Phoenix attic or on a roof, the practical worry is movement more than sun: expansion, and pipe sagging between supports. Both plastics soften with heat, so follow the support spacing for the pipe you have. The drain slope rules and vent basics apply the same way to either material.

### What about noise and fire-rated walls?

Sound: PVC is denser (1.40 versus 1.05), and people often say that makes it quieter. But no code or manufacturer table I found rates DWV noise for either plastic, so treat it as a rumor. If a bathroom stack runs beside a bedroom, insulate the wall cavity whichever pipe you use.

Fire: Charlotte's property table lists both materials as self-extinguishing in the burning-rate test. That does not make them fireproof. Where a plastic pipe passes through a fire-rated floor or wall, the opening needs an approved fire-stop system, and it has to suit the pipe. Charlotte warns that the system must be protected from "fire-stopping materials" that are not compatible with the plastic. Match the pipe material to the listed firestop product.

Yes, both are accepted for home drains and vents. The 2024 IPC pipe tables list ABS (D2661, F628) and PVC (D2665, F891) for above-ground drainage and vent piping, for building drains, and for building sewers. Section 703.2 names both as acceptable in filled or unstable ground. Phoenix adopted both the 2024 IPC and the 2024 Uniform Plumbing Code, with Phoenix amendments, effective August 1, 2025, under Ordinance G-7397. I verified the IPC tables and did not read the UPC tables, so if your job is under the UPC, ask the city's plan reviewer before assuming the same answer. Other Valley cities set their own adoptions, so the same check applies there.

### Which is more common in Phoenix homes?

I could not find a published count of ABS versus PVC in Phoenix-area houses, so I won't guess a share. It varies by builder and year, and it can even change within one house, with ABS under the slab and PVC above it, or the reverse. The quick way to know is to look: black pipe is ABS, white or cream is PVC. Cast iron, older clay and Orangeburg are a different story, covered in our pages on cast iron drain lifespan and Orangeburg pipe.

If you are repairing an existing line, match the pipe you have, or use the right transition adapter. If you are choosing for new work, the plumber's habits, your city's plan and the inspector matter more than any chart, because both plastics work. HQ Plumbing & Air is licensed and insured and gives you the price up front, so you can ask us to look at your drain line and tell you what is in the wall. That's the simple version.