6 Plumbing Pipe Types That Matter More Than the Fixture
Plumbing pipes are invisible until something goes wrong. A slow leak, low pressure, discolored water, or a renovation that opens the walls is usually when the question comes up: what kind of pipe is actually in here, and should it stay?
Over time, I stopped thinking of plumbing pipes as interchangeable. Each one behaves differently, ages differently, and reacts to heat, pressure, and installation mistakes in its own way. These are the six pipe types I see most often in homes and how I personally decide when each one makes sense.
PEX Pipe
PEX (cross-linked polyethylene) i is the pipe I see used most often in newer homes and renovations, and for good reason.
It’s flexible, easy to route through walls, and faster to install than rigid materials. When done right, it reduces joints, which means fewer potential leak points. I also like that it tolerates minor movement in the house without stressing fittings.
Where I pause is long-term confidence. PEX quality varies by manufacturer, and installation matters more than people admit. Poorly crimped fittings are where problems usually show up.
I choose PEX when:
- I need flexibility behind finished walls
- Speed of installation matters
- The plumbing layout has many turns
PVC Pipe
PVC (polyvinyl chloride) pipe is not a water supply pipe in my mind. It’s a drainage pipe.
It works well for drain, waste, and vent lines. It’s lightweight, affordable, and easy to cut and glue. For gravity-fed systems, it does the job without drama.
What I avoid is using it anywhere pressure or heat comes into play. It’s not designed for that, and I don’t like pushing materials beyond their comfort zone.
I use PVC for:
- Drain and vent lines
- Waste piping
- Exterior irrigation
Rigid Copper Pipe
Copper is still the pipe I trust the most for water supply when budget allows.
It handles heat, pressure, and time better than most materials. When installed properly, it can last decades without issue. I also appreciate that it doesn’t rely on plastic for potable water.
The downsides are cost and skill. Bad soldering is worse than no soldering at all. And copper prices fluctuate, which can change project costs quickly.
I choose copper when:
- Longevity matters more than cost
- The pipe will be exposed or accessible
- Hot water lines are involved
ABS Pipe
ABS (acrylonitrile butadiene styrene) pipe feels like PVC’s tougher cousin, but it comes with limitations.
It’s commonly found in older homes and is still used for drain and vent systems in some regions. It handles impact well, but sunlight and heat can degrade it over time.
The biggest factor with ABS is code approval. Some areas allow it, others don’t. I never assume.
I use ABS when:
- It’s already present and permitted
- The application is strictly drainage
- Local codes allow it
Flexible or Braided Pipe
These are connection pipes, not system pipes.
Braided stainless steel lines are convenient for sinks, toilets, and appliances. They’re easy to replace and forgiving during installation. I treat them like wearable parts, not permanent infrastructure.
What I never do is hide them behind walls or floors. When these fail, they fail suddenly.
I use flexible lines for:
- Final appliance connections
- Exposed, accessible areas only
Galvanized Steel and Cast Iron
When I see these, I assume age and plan accordingly.
Galvanized steel corrodes from the inside. Even if it looks fine outside, internal buildup often restricts flow. Cast iron lasts longer, especially for drains, but once it starts to fail, replacement is usually inevitable.
I don’t install either in new residential work unless there’s a specific reason.
I treat these as:
- Materials to assess, not preserve
- Candidates for replacement during renovations
How I Choose the Right Plumbing Pipe
I don’t choose based on trends or price alone. I look at four things every time:
- Function: supply, drain, or connection
- Access: behind walls or exposed
- Longevity: will this be opened again
- Code: what’s actually allowed here
My general hierarchy:
- Copper or PEX for supply
- PVC or ABS for drains
- Braided lines only for final connections
- Galvanized and cast iron only if already present
Beyond the common options, there are several other plumbing pipe variations used in specific situations or older homes.
- CPVC – Handles hot water but becomes brittle over time
- Polypropylene (PP-R) – Heat-fused system common in Europe and commercial builds
- HDPE – Used mainly for underground or exterior water lines
- Lead – Found in very old homes and should be replaced immediately
- Brass – Mostly used for fittings, rarely for full pipe runs
- Concrete – Limited to sewer and storm drainage, not interior plumbing
The right pipe is the one you never have to think about again once the wall is closed.