Copper is the common material used for water supply lines.

Copper is the old faithful of water supply lines. When you hear myths about which pipe material to trust, copper often tops the list. There’s a good reason for that, too. Copper has kept countless homes safe and dry for decades, if not a century or more. Let me walk you through why it stays popular, what the alternatives bring to the table, and how to decide what fits your project best.

Copper: why it’s so dependable

Copper isn’t flashy, but it’s sturdy. Here are the standout reasons people reach for copper pipes for water supply:

• Tough against heat and pressure. Hot water is hard on plumbing, but copper can handle temperature swings and pressure without flaking or cracking the way some plastics can over time.

• Corrosion resistance. Copper resists the kind of corrosion that can ruin pipes and nick water quality. It doesn’t dissolve or degrade quickly when in contact with drinking water.

• Antimicrobial edge. Copper has natural properties that can deter some microbial growth along the pipe surface. It’s not a cure-all, but it’s a helpful bonus in the water column.

• Easy to join (with the right technique). Soldering copper joints is a well-understood skill. Type K, L, and M copper pipes—plus the right fittings—make secure, long-lasting connections possible. For many pros, this is a comfort factor: you can see the joints, you can test them, you can repair them.

Copper comes in several wall thicknesses (the K, L, and M designations you’ll see on the workbench). Thicker walls (like Type K) are common in underground or heavy-use scenarios; thinner walls (like Type M) are often found in residential interior runs. Picking the right grade comes down to where the pipe lives and what it carries.

PVC and CPVC: lighter, cheaper, and not your hot-water friend

PVC and CPVC get a lot of love for cost and ease, especially for long, straight runs in new construction or in retrofit projects. Here’s the lay of the land:

• PVC (polyvinyl chloride) is lightweight and inexpensive. It’s great for cold-water lines and some drainage systems. It’s easy to cut and glue, which saves time on big runs.

• CPVC (chlorinated polyvinyl chloride) handles hot water better than standard PVC. It’s a middle ground: still lighter and cheaper than copper, but more heat-tolerant than regular PVC.

The catch? For hot water, copper usually has the edge. Plastic materials can soften or degrade under sustained high temperatures, which is why you’ll often see CPVC used for hot water in some homes, and copper reserved for the hottest portions of a system. If you’re planning a run that might see high heat or frequent temperature swings, copper’s performance under stress is a reassurance.

Lead and concrete: a cautionary tale and a practical note

Historically, lead pipes were part of many old homes. We now understand the health risks posed by lead in drinking water, especially for kids and pregnant people. Because of that, lead is largely phased out in new plumbing, and where it still exists, it’s being replaced.

Concrete isn’t a water-supply material for homes in the way copper or PVC is. You’ll see concrete more in underground drainage or trench work, or in specific large-scale sewer projects. It doesn’t belong in a household hot- or cold-water line as a primary supply pipe. So, when you hear about “concrete pipes” for home water supply, it’s usually a misinterpretation or a project-specific exception.

Choosing what fits your home

Here’s how to think about it, without the ceremonial drama:

• Consider temperature. If hot water is involved, copper’s heat resistance is a strong point. PVC remains fine for cold feeds, but for hot water, copper tends to win.

• Think about run length and routing. For long, straight runs in finished walls or basements, plastic can save weight and installation time. If you’re tying into an older copper system, copper may be the smoothest path to maintain uniform pressure and joints.

• Account for cost. Copper costs more up front, but it can pay off over time with durability and reparability. If your project is budget-conscious and mostly cold water, CPVC or PVC might be a practical choice.

• Local codes matter. Some jurisdictions have strong preferences or outright requirements about pipe materials for different sections of a home. Always check the plumbing code in your area or chat with a licensed plumber to stay compliant.

A practical note on installation

If you’re doing the work or supervising it, a few practical points can save headaches:

• Tools you’ll likely use with copper: a tubing cutter (for clean, straight cuts), a deburring tool (to smooth the inside edge so water flows cleanly), a propane or oxy-acetylene torch for soldering, and lead-free solder with a compatible flux. If soldering isn’t your thing, push-to-connect fittings from brands like SharkBite are a popular alternative. They let you snap fittings onto copper with a little push and without heat, which is handy in tight spaces.

• Fitting choices. For copper, you have a choice between sweat-solder joints and mechanical fittings. Sweat joints are durable and traditional, but they require heat and flux. Mechanical options (like compression or push-fit) can speed things up and reduce fire risk.

• Sizing matters. Copper comes in different diameters. A common residential choice is 1/2 inch or 3/4 inch for water supply lines, with thicker-wall variants where required. Getting the size right helps prevent friction losses and pressure drops.

• Transition points. If you’re combining copper with plastic or steel in a system, you’ll want a dielectric or anti-corrosion union at the junctions to prevent galvanic corrosion. It’s one of those small details that prevents big headaches later.

Maintenance and longevity: what to expect

Copper plumbing, when installed well, tends to behave. You’ll get decades of service in many homes. Here are a few real-world tips:

• Protect joints. A well-made joint is a promise of years of leak-free service. Make sure joints are clean, properly fluxed, and not overheated, which can damage fittings.

• Watch for pitting and corrosion in certain water chemistries. Very acidic or highly aggressive water can cause trouble for copper in rare cases. If your area has particularly challenging water chemistry, a local plumber might suggest an internal treatment or a coated pipe option.

• Inspect proactively. Create a habit of checking accessible sections under sinks or along basement runs. Early detection of a slow drip can save a lot of drama.

A few quick questions people ask, and a straight answer

• Is copper always the best choice? Not always. For cold-water runs in a budget-conscious project, PVC or CPVC can work well. For hot water or where durability and repairability are priorities, copper often makes more sense.

• Can copper touch steel pipes? It can, but it’s good practice to use dielectric unions at metal-to-copper joints to minimize corrosion over time.

• Do I need a plumber to install copper? It depends. A confident DIYer with the right tools can do many copper installations, especially simple runs. For gas-tight heat-soldering and any work in live systems, a licensed pro is the safer bet.

Copper’s place in the bigger picture

If you map out the typical bundle of questions a student or professional might encounter about water supply lines, copper keeps showing up as a reliable default. It’s not the only option, but its mix of durability, heat tolerance, and ease of repair makes it a strong baseline choice for many homes.

A few industry-flavored metaphors you’ll recognize

• Think of copper like a road built to handle heavy trucks. It’s not the lightest option, but it’s resilient, predictable, and long-lasting.

• Jumping from copper to plastic mid-run can feel like switching lanes on a busy highway. If you do it thoughtfully, with proper fittings, it’s perfectly fine. If you rush, you’ll regret the bottlenecks and leaks.

• The connection between copper and water quality is less about magic and more about surface behavior. Copper pipes don’t contaminate water the way some old materials might, and they offer a robust barrier against certain types of degradation that plague other choices.

A closing thought

For anyone wiring up a home’s lifelines, copper stands out as a dependable veteran. It’s ready for heat, it resists the kind of corrosion that plagues other materials, and it’s made for the kind of joints a trained professional can deliver reliably. Of course, the right material for a given project depends on temperature, run length, budget, and code requirements. But if you’re aiming for a durable, fight-the-test-of-time water supply line, copper is a matched partner to most households.

If you want to explore this topic further, you could look into how a typical copper line is sized in residential plans, or what “Type L” copper actually means in terms of thickness and performance. You might also check out common fittings from trusted brands like SharkBite, Ridgid, and Milwaukee—tools and fittings that keep the process smooth when you’re on-site. And, as always, keep safety front and center: turn off the water, relieve pressure, wear eye protection, and know when it’s time to call a professional.