Types of Plumbing Pipes: Supply and Drain Materials Explained

The types of plumbing pipes in a home split into two jobs: supply lines that carry pressurized water in (PEX, copper, CPVC, and legacy galvanized steel or polybutylene) and drain-waste-vent lines that carry water and waste out (PVC, ABS, and older cast iron). This overview maps every common material, where it belongs, how long it lasts, and what it costs. Related: plumbing pipe sizes.

What are the main types of plumbing pipes?

Modern homes use about eight pipe materials, sorted by function. Five run water under pressure, and three move waste out by gravity. Copper and PEX dominate new supply work, CPVC fills a middle lane, and PVC handles most drains. Galvanized steel, polybutylene, and cast iron are legacy materials you mostly find in older houses.

The table below is the fast reference: what each pipe does, how long it typically lasts, and its relative material cost. Prices are for the pipe itself, not installed labor, and lifespan and approved uses vary by water chemistry and local code. Follow the links for the deep-dive on each material.

Which types of plumbing pipes carry your water supply?

Supply pipes hold pressurized potable water, so they need strength, heat tolerance, and a lead-free rating under NSF/ANSI 61 and 372. Today that job goes mostly to PEX, copper, and CPVC. Two older materials, galvanized steel and polybutylene, still turn up in existing homes and drive many repipe jobs.

PEX

PEX is flexible cross-linked polyethylene, now the default for new residential supply. It runs $0.40 to $2 per foot, installs with crimp or expansion fittings instead of soldering, and its flex resists freeze bursts better than rigid pipe. It cannot be used outdoors in sunlight, and its fittings slightly narrow flow. Expect 40 to 50 years of service.

PEX comes in three grades: PEX-A is the most flexible and forgiving of freezes, PEX-B is the common mid-cost option, and PEX-C sits at the budget end. Connections use crimp rings, cinch clamps, or cold-expansion fittings, so a plumber can run continuous lengths through walls with fewer joints to leak.

Copper

Copper is the long-standing premium supply pipe, valued for a 50 to 70 year lifespan and high heat tolerance. It comes in types M, L, and K by wall thickness, with type M common indoors. It resists bacteria but costs $2 to $8 per foot and needs soldered or pressed joints. Acidic water can cause pinhole leaks over time.

Copper still wins where PEX and plastic fall short: exposed exterior runs that see sunlight, near-boiler connections that carry high heat, and jobs where a homeowner wants the longest proven track record. The tradeoff is price and labor, since copper prices swing with the commodity market and joints take skilled work.

CPVC

CPVC is chlorinated PVC rated for hot and cold potable water, unlike standard PVC. It costs $0.50 to $1.50 per foot, joins with solvent cement, and resists chloramine better than PEX in some water systems. It is rigid, becomes brittle with age, and needs cure time before pressure testing. Typical service runs 40 to 50 years or more.

Galvanized steel and polybutylene

Both are legacy supply materials you replace, not install. Galvanized steel, common before the 1960s, corrodes from the inside, restricting flow and shedding rust after 40 to 50 years. Polybutylene, installed roughly 1978 to 1995, cracks and fails at fittings and is often flagged by home insurers, which makes it a frequent repipe target.

What pipes handle drains, waste, and venting?

Drain-waste-vent (DWV) pipes move wastewater out by gravity and vent sewer gas, so they run at low pressure and larger diameters than supply lines. PVC handles most of this work today, ABS covers it in some regions, and cast iron survives in older homes. See the full breakdown of drain and sewer pipe materials for buried lines.

PVC is the white plastic standard: cheap at $0.50 to $3 per foot, easy to solvent-weld, and good for 50 to 100 years. ABS is the black plastic equivalent, joined in one step without primer, and favored in some Western and Midwestern codes. Cast iron, found in pre-1970 homes, is heavy and quiet but rusts through after 75 to 100 years. Local code decides which drain material is approved in your area.

DWV systems also include vent piping, usually the same PVC or ABS, that lets sewer gas escape through the roof and keeps traps from siphoning dry. Drain lines run larger than supply, commonly 1.5 to 4 inches, and slope about 1/4 inch per foot so gravity does the work.

How do you choose the right plumbing pipe?

Choosing a pipe starts with the job, then budget, water conditions, and code. Supply and drain materials are not interchangeable, and the wrong pick fails inspection. Use this order when planning a repipe, a remodel, or a new run so you match strength, lifespan, and cost to the application.

1. Match the pipe to its job first: pressurized supply (PEX, copper, CPVC) or gravity drain (PVC, ABS, cast iron).
2. Check local code for approved materials, since many areas allow only specific pipes for potable water or DWV.
3. Weigh cost against lifespan: PEX and PVC save money upfront, while copper and cast iron cost more but last longer.
4. Factor in water chemistry and climate: acidic water can pit copper, and freeze-prone runs favor flexible PEX.
5. Consider the install method and permits, since soldering, solvent cement, and press tools each carry different labor and cure time.

How can you tell what pipes you already have?

Color, texture, and the home’s build year are the fastest ways to identify existing pipe. Exposed runs in a basement, crawlspace, or under a sink give you the clearest look. If flow is weak or water runs rust-colored, the material and its age often explain why, and a licensed plumber can confirm before any repipe.

• PEX: flexible tubing in red, blue, or white, with printed markings along the pipe.
• Copper: rigid, reddish-brown metal that dulls to brown or green as it oxidizes.
• CPVC: rigid cream or tan plastic, stamped with a size and rating.
• PVC: rigid white plastic drain pipe, the most common modern DWV material.
• ABS: rigid black plastic used for drains in some regions.
• Galvanized steel: dull gray, threaded metal that sounds solid when tapped.
• Cast iron: heavy, dark drain stacks, thicker and quieter than plastic.

Frequently asked questions

What are the most common types of plumbing pipes?

The most common plumbing pipes are PEX, copper, and CPVC for pressurized water supply, plus PVC and ABS for drains, waste, and venting. Copper and PEX handle most new supply work today. Galvanized steel, polybutylene, and cast iron still exist in older homes but are rarely installed new.

Which pipe is best for water supply lines?

PEX and copper are the top choices for water supply. PEX costs less (roughly $0.40 to $2 per foot), installs fast, and resists freeze bursts. Copper lasts 50 to 70 years and tolerates high heat but runs $2 to $8 per foot. CPVC is a lower-cost middle option. The best pick depends on budget, water chemistry, and local code.

What are drain pipes made of?

Most modern drain, waste, and vent pipes are white PVC, which is cheap and long-lasting. Some regions use black ABS for the same job. Homes built before the 1970s often have cast iron drain stacks, which are heavy, quiet, and prone to rust after 75 to 100 years. Clay was common for older buried sewer lines.

How do I tell what type of pipes I have?

Color and location are the fastest clues. PEX is flexible and red, blue, or white. Copper is reddish-brown and rigid. CPVC is cream or tan. PVC drains are white, ABS drains are black. Galvanized steel looks dull gray and threaded. The home’s build year narrows it further, since materials changed by decade.

What is the longest-lasting plumbing pipe?

Cast iron and copper last longest, often 50 to 100 years. Cast iron drain lines can reach 75 to 100 years before rust takes over, and copper supply lines often run 50 to 70 years. PVC drains can last 50 years or more. Actual lifespan depends on water chemistry, installation quality, and local conditions.

Which plumbing pipes should be replaced?

Polybutylene, installed roughly 1978 to 1995, is failure-prone and often flagged by insurers, so replacement is common. Corroded galvanized steel that restricts flow or leaks rust-colored water is another replacement candidate. Any lead service line should be replaced. A licensed plumber can confirm the material and whether repiping makes sense for your home.

Last reviewed: September 2026.