Cast iron, galvanized, copper, CPVC, polybutylene, PEX: what pipes are in your Florida home?

Nobody thinks about the pipes until one lets go. But the material in the walls decides what kind of failure you are likely to get, whether an insurer will ask about it, and whether the fix is a repair or a repipe. In Southwest Florida the answer follows the calendar closely enough that the year the house was built tells you most of it, and a few minutes with a flashlight tells you the rest.

A decade-by-decade guide for Lee and Collier County

• Before the mid-1970s. Drains are cast iron under the slab and in the walls, sometimes with a clay pipe lateral to the street in the oldest Fort Myers neighborhoods. Supply is galvanized steel in the oldest homes and copper in most from the 1960s on. These are the homes where the drains fail first.
• Mid-1970s to mid-1980s. PVC took over for drains, white and glued. Supply is copper, run through the slab or the walls. This is the largest group of homes now producing copper pinhole leaks.
• Late 1970s to mid-1990s. Polybutylene arrived as a cheap, fast supply pipe, gray and flexible, and went into a large share of the homes built in the boom years in Cape Coral, Lehigh Acres, and Bonita Springs. It was pulled from the market in the mid-1990s after it failed everywhere. Copper and early CPVC ran alongside it.
• Mid-1990s through the 2000s. CPVC is the standard supply material, cream or light yellow, rigid, glued. Drains are PVC. Most of the homes built in the 2000s boom fall here.
• 2010s on. PEX, flexible tubing in red, blue, or white, with copper or plastic fittings, is the common supply. Drains are PVC.

Every rule has exceptions. A 1985 home that was repiped in 2015 has PEX. A 1972 home may have been partly updated. The list below is how you find out what actually is there.

How to tell them apart by look

• Cast iron. Dark gray or black, heavy, rough, about the diameter of a coffee can for the main drain. Rust blisters and scaling on the outside; a dull thud when tapped.
• Galvanized steel. Silver-gray metal pipe with threaded fittings, often rust stained at the threads. Supply lines only. A magnet sticks to it.
• Copper. Reddish brown, sometimes dull, sometimes green at the joints. Soldered fittings. A magnet does not stick.
• PVC. White rigid plastic with printing along the side, glued fittings. Drains, vents, and irrigation. Not for hot water.
• CPVC. Cream, light yellow, or tan rigid plastic, thinner than PVC, with glued fittings. Hot and cold supply. Printed with “CPVC” along the length.
• Polybutylene. Gray, sometimes blue or black, flexible plastic with crimped copper or plastic fittings. Marked “PB2110” along the length. Supply only.
• PEX. Red, blue, or white flexible tubing with crimp rings or expansion fittings. Marked “PEX” along the length. Supply only.

Supply or drain?

Supply lines are small, roughly the diameter of a finger or a thumb, and there are two of them at every fixture: hot and cold. Drains are large, from wrist to coffee-can size, one per fixture, and they run downhill. Cast iron, PVC, and ABS are drain materials. Galvanized, copper, CPVC, polybutylene, and PEX are supply materials. If you know which system you are looking at, you have narrowed the list by half.

How each one fails here

• Cast iron corrodes from the inside in our warm, wet ground, especially under the slab. The bottom of the pipe channels out, roots find the joints, and the first signs are slow drains, sewer smell, and backups.
• Galvanized rusts shut. Pressure drops across the whole house, and the water runs orange after sitting overnight.
• Copper gets pinholes. Our water chemistry, velocity in undersized lines, and contact with concrete all thin the wall. Pinholes under the slab show up as warm floors, a running meter, and a water bill.
• Polybutylene breaks down from chlorine and chloramine and cracks at the fittings. It gives little warning.
• CPVC goes brittle with decades of heat, especially in a hot attic or garage. It cracks at fittings and can shatter when a stuck valve is forced.
• PEX has the shortest track record but the fewest known problems. Keep it out of sunlight, and watch for fitting leaks in early installs.

How to check without opening a wall

1. The water heater. The two pipes on top are the supply lines for the house. Whatever material they are, most of the house probably matches. This is the single best place to look.
2. Under every sink. The pipes coming out of the wall to the angle stops are the supply. The larger pipe with the curved trap is the drain. Check the kitchen, every bath, and the laundry.
3. The garage. Lines are often exposed near the water heater, the washer box, and where the main enters.
4. The cleanout outside. A capped pipe near the front or side of the house. White cap is PVC. A heavy rusted cap or a brass plug in a black pipe is cast iron.
5. The attic. Look near the hatch. Repiped homes have PEX or CPVC running across the trusses. Original 1980s homes may have polybutylene or copper up there too.

Take a photo of each with the printing on the pipe visible. That is enough to identify almost any material without guessing.

What to do about what you find

Identifying the pipe is homeowner work. Doing something about it is not. Polybutylene gets scheduled for replacement regardless of condition. Galvanized supply is a repipe. Copper with pinholes is on the clock, and the count of leaks tells you how long. Cast iron drains get a camera inspection so you know how much is left before you spend anything. CPVC and PEX get left alone unless they are leaking.

If you are not sure what you are looking at, send us the photos and the year the house was built. We will tell you what is in the walls, what it tends to do here, and whether it is something to plan around or something to fix now.