Building the Future

Before you build, compare.

Today’s building owners and facility managers face a daunting challenge: How do you ensure that your plumbing infrastructure is built to last while meeting sustainability goals, safety regulations and budget constraints? The market is flooded with materials claiming to be the best solution and with evolving codes and environmental pressures, the stakes have never been higher.

One of the biggest debates in the industry revolves around material selection: traditional cast iron soil pipe and fittings or plastic alternatives like PVC and ABS? Each option presents a different set of benefits and drawbacks but sorting through the noise to find a solution that balances performance, cost and sustainability is no small task.

Making the wrong choice can lead to increased maintenance, frequent replacements, unhappy tenants and even fire or safety risks—problems no facility manager wants to deal with. This article aims to cut through the confusion, addressing key factors such as sustainability, durability, noise control, and fire safety. After all, the better your information at the beginning, the better your build in the long run.

Comparison 1: Sustainability

Recyclability

Sustainability has become a non-negotiable priority in modern construction. When it comes to environmental impact, cast iron made in America has a compelling advantage: it is made from more than 96% post-consumer recycled materials and is 100% recyclable at the end of its life. This means that instead of becoming landfill waste, cast iron soil pipe can be repurposed, significantly reducing its environmental footprint. PVC, on the other hand, is a different story. While some can technically be recycled, the reality is that most ends up as waste. And once plastic breaks down, it releases microplastics into the ecosystem.

Longevity & durability

It’s one thing for a material to be recyclable, but if it doesn’t last long, it’s not really sustainable. While PVC pipes can degrade within a few decades—especially in demanding environments—cast iron has a service life of 50 years or more. Many historic buildings still rely on original cast iron plumbing installed a century ago. Fewer replacements mean less material waste and a lower environmental impact over time.

Lower carbon footprint

Manufacturing processes also matter when evaluating sustainability. The production of PVC and other plastic piping generates high levels of greenhouse gas emissions, from cradle to grave, whereas cast iron is produced through more sustainable methods, including the use of recycled materials. The energy required to manufacture, transport, install and dispose of plastic piping can make it far less environmentally friendly than it appears on paper.

LEED & Green building contributions

Facility managers focused on achieving LEED certification or meeting sustainability benchmarks will find that cast iron plays a valuable role. Its recyclability, long lifespan and ability to reduce environmental impact contribute to green building initiatives, helping facilities meet regulatory and sustainability goals.

Sustainability Pipe Pick: Cast iron

Comparison 2: Resilience & performance

Fire resistance

Safety is a major concern in any building, particularly in high-occupancy environments like hospitals, apartment complexes and commercial facilities. One of the most overlooked risks with plastic piping is its combustibility. PVC burns easily, releases toxic smoke and requires additional protective measures to meet code, such as complex firestop and/or fire wrap–all of which increase installed cost. Cast iron, on the other hand, is non-combustible and naturally fire-resistant—providing built-in protection without the need for extra safety measures.

Structural strength

Your plumbing system takes a beating over the years. Between heavy usage, extreme weather and seismic activity, pipes need to be tough. Which PVC, unfortunately, is not. It warps, cracks and breaks under stress. Cast iron, on the other hand, stands up to just about anything. If you want a system that won’t buckle under pressure, cast iron is the way to go.

Corrosion resistance

Advances in coatings technology have made cast iron pipe more corrosion resistant than ever. Today’s cast iron soil pipes are built to handle even the most demanding environments, such as low flow plumbing systems, making it a great choice for commercial kitchens, facilities which encounter aggressive wastes and coastal areas.

Resilience and Performance Pipe Pick: Cast iron

Comparison 3: Noise control

Recent studies by USA Today indicate that plumbing noise is the number one complaint in the hospitality industry. Noise is an especially important consideration in any project that has shared walls, such as multi-family residential, hotels, medical facilities, educational buildings and office buildings. So how do cast iron pipes compare with plastic piping systems such as PVC when it comes to noise?

Acoustic performance

The denser the material, the quieter it will be. Plastic piping systems require added insulation wrap and isolation brackets for quieter performance, which ultimately increases costs and further complicates installation. Cast iron, on the other hand, naturally dampens sound due to its dense composition and jointing methods—reducing wastewater noise and total installed cost while improving the comfort of tenants and employees.

Real-world applications

Hospitals, hotels and residential complexes frequently choose cast iron over plastic for its sound- dampening capabilities. The ability to create a quieter, more comfortable environment makes a difference in tenant satisfaction and building quality.

Noise Control Pipe Pick: Cast iron

Comparison 4: Cost considerations

As a rule of thumb for commercial building, the piping systems account for about 1% of the overall project cost. The drain, waste and vent (DWV) piping is just one component of the piping systems in a building. So the cost of DWV pipe is a small fraction of the overall cost of the project. That said, it is still important to not only look at the initial material cost, but, more importantly, the total installed cost. Only then can you truly decide which material is right for you.

Initial cost vs. Lifetime cost

Although the initial material cost is more for cast iron than PVC, there are a host of factors that increase the total installed costs of plastics as compared to cast iron systems. Plastics, for example, require more fire-stop material, more hangers and support, and additional insulation, all of which require more labor to install. Plus, their shorter lifespan and higher maintenance requirements lead to greater expenses over time. Cast iron’s durability means fewer repairs, fewer replacements and a lower total cost of ownership.

Reduced maintenance & replacement

Plastic pipes are prone to cracking, sagging and degrading due to exposure to extreme temperatures, chemicals and physical stress. These weaknesses often translate into higher maintenance costs. Cast iron, with its superior strength and longevity, minimizes these concerns.

Insurance & liability

Fire-resistant materials aren’t just about safety — they can also save you money. Because cast iron doesn’t burn, insurance providers may offer lower rates for buildings that use it. PVC’s fire risk, on the other hand, could mean higher premiums and added liability.

Cost Comparison Pipe Pick: Cast iron

PVC or cast iron? There’s really no comparison.

Given the overwhelming amount of information — and misinformation — available, it’s easy for facility managers to feel lost when choosing the right materials. That’s where the Cast Iron Soil Pipe Institute comes in.

As an independent authority, CISPI doesn’t just advocate for cast iron because it’s in our name — we provide expert guidance based on decades of research, testing and real-world application. CISPI helps facility managers navigate complex building codes, evaluate true material costs and make decisions rooted in facts rather than marketing claims. And yes, CISPI will even tell you when PVC is the right choice for your situation.

At the end of the day, choosing the right plumbing infrastructure isn’t just about today — it’s about making sure your building is built to last. Cast iron has proven itself time and time again, delivering strength, safety and sustainability.

For more information, specifications and case studies, visit CISPI.org/ironcladtruth and get the Iron-Clad Truth about building materials for your next project.