Pipe Material Types
Identifying pipe materials is a key part of plumbing inspection. Each material has expected lifespan, common failure modes, and maintenance requirements.
Copper
Copper is the most common supply piping in homes built since the 1960s. It resists corrosion, has a long lifespan (50+ years), and doesn't affect water quality.
Common copper issues:
- Pinhole leaks from corrosive water chemistry
- Green patina or white mineral deposits at joints
- Solder joint failures from age or improper installation
Copper piping generally indicates a well-built plumbing system with decades of remaining life.
Galvanized Steel
Galvanized steel pipes were standard in homes built before 1960. The zinc coating that protects the steel corrodes over time, leading to restricted flow and eventual leaks.
Signs of failing galvanized pipes:
- Reduced water pressure, especially at upper floors
- Rust-colored water when first running faucets
- Visible rust or corrosion at threaded connections
- Leaks at joints and fittings
Expected lifespan: 40-70 years. Most galvanized piping in older homes is at or past end of life. Full repiping typically costs $4,000-15,000 depending on home size and accessibility.
Polybutylene (PB)
Polybutylene is a gray plastic pipe used from approximately 1978 to 1995. It was installed in millions of homes but has a documented history of premature failure.
PB pipe fails from the inside out when exposed to chlorine and other oxidants in municipal water supplies. Failures are sudden and can cause significant water damage.
Identification: Gray flexible plastic, typically with copper or plastic fittings. Markings include "PB" followed by numbers.
Most insurers and lenders consider polybutylene a material defect. Replacement is typically recommended. See the dedicated polybutylene article for detailed information.
PEX (Cross-Linked Polyethylene)
PEX is the current standard for residential water supply piping. It's flexible, resistant to freezing damage, and installs quickly. Colors indicate function: red for hot, blue for cold, white for either.
PEX has been in use since the 1980s in Europe and the 1990s in North America. No significant failure patterns have emerged. Expected lifespan exceeds 50 years based on accelerated testing.
Common PEX issues are usually installation-related:
- Improper support causing sagging
- UV exposure degradation (outdoor installation without protection)
- Fitting compatibility issues with older PEX types
CPVC (Chlorinated Polyvinyl Chloride)
CPVC is a cream or tan colored rigid plastic pipe. It handles hot water (unlike regular PVC) and costs less than copper.
CPVC becomes brittle with age and can crack or shatter from impact. It's more susceptible to chemical damage than PEX or copper.
Common CPVC issues:
- Brittleness and cracking in older installations
- Failure near water heaters from heat exposure
- Chemical incompatibility with some pipe support materials
Cast Iron (DWV)
Cast iron was the standard drain, waste, and vent material for decades. It's heavy, durable, and quiet. Cast iron drain lines can last 80-100 years.
Failure signs:
- Rust holes visible on exposed sections
- Sagging or bellied sections
- Orange rust stains at joints
- Leaks at hub connections
Replacement is expensive due to weight and installation complexity. Spot repairs are possible for isolated failures.
ABS and PVC (DWV)
ABS (black) and PVC (white) are modern drain pipe materials. Both have long lifespans and require little maintenance.
Common issues:
- Improper slope causing slow drainage
- Missing cleanouts
- Incorrect transitions between materials
- Connections not properly glued
These are installation issues rather than material defects. Properly installed ABS and PVC should last indefinitely.
Water Supply System Findings
Water supply inspection covers the main line, distribution piping, shut-off valves, and water pressure.
Water Pressure
Normal residential water pressure is 40-80 PSI. Inspectors test pressure at an exterior hose bib or laundry connection.
Pressure issues:
- Below 40 PSI: Low flow at fixtures, may indicate supply restriction or failing pressure regulator
- Above 80 PSI: Stresses pipes and fixtures, shortens appliance life, may cause water hammer
- Pressure fluctuations: May indicate well pump issues or municipal supply problems
High pressure is addressed with a pressure-reducing valve (PRV). Low pressure requires investigation of the cause.
Shut-Off Valves
Every plumbing fixture should have accessible shut-off valves. Main shut-off valves control water to the entire house.
Common valve issues:
- Gate valves corroded and inoperable (common in older homes)
- Missing individual fixture shut-offs
- Valve handles broken or missing
- Active leaks at valve stems or connections
Replacing old gate valves with quarter-turn ball valves improves reliability. Individual valve replacement costs $50-150 per fixture.
Supply Line Leaks
Visible leaks at supply connections are common findings. Sources include:
- Compression fittings at angle stops
- Flexible supply line connections to fixtures
- Threaded connections at water heaters
- Solder joints on copper piping
Active drips need repair. Mineral deposits or staining indicate past or intermittent leaks that should be monitored.
Cross-Connections
A cross-connection allows non-potable water to enter the potable supply. Common examples:
- Garden hose submerged in a pool or pond
- Irrigation systems without backflow preventers
- Handheld shower heads below flood level rim
Cross-connections are code violations and health hazards. Corrections typically require anti-siphon devices or vacuum breakers.
Drain System Findings
Drain inspection includes functional testing at fixtures, visual inspection of accessible piping, and assessment of venting.
Slow Drains
Slow drains have various causes:
- Single fixture slow: Trap or fixture drain obstruction
- Multiple fixtures slow: Branch line blockage
- Whole-house slow drains: Main line obstruction or root intrusion
- Gurgling at fixtures: Venting problems
Isolated slow drains are minor. Widespread drainage problems warrant sewer camera inspection to identify the cause and location.
Drain Leaks
Drain leaks are less obvious than supply leaks because they only occur during fixture use. Common locations:
- P-trap connections under sinks
- Slip joints on PVC drain assemblies
- Toilet wax ring failures
- Shower pan failures
- Washing machine standpipe connections
Stains, mold, or musty odors near drain locations suggest active or intermittent leaks even when no water is visible.
Venting Problems
Drain vents allow air to enter the system, enabling proper drainage and preventing siphoning of fixture traps. Vent problems cause:
- Slow drainage despite clear pipes
- Gurgling sounds when fixtures drain
- Sewer odors in the house (traps siphoning dry)
Common vent issues:
- Vents blocked by debris, ice, or animal nests
- Improper vent pipe sizing or configuration
- Missing vents on island sinks or other isolated fixtures
Main Sewer Line Concerns
The main sewer line carries all waste from the house to the municipal sewer or septic system. Inspection scope typically ends at the house connection; underground lines require camera inspection.
Signs of main line problems:
- Slow drains throughout the house
- Sewage backup in basement or lowest-level fixtures
- Wet or unusually green areas in the yard over the line
- Multiple drain blockages despite clear individual lines
Sewer camera inspection costs $100-400 and is recommended for older homes or when symptoms suggest main line issues.
Fixture Findings
Plumbing fixtures are tested for function and inspected for visible defects.
Faucets and Valves
Common faucet findings:
- Drips and leaks (washer or cartridge wear)
- Low flow (aerator clogging or supply restriction)
- Loose handles or mounting
- Cross-connection risk from pull-down sprayers
Most faucet repairs are under $100. Full replacement ranges from $150-500 installed.
Toilets
Toilet inspection covers:
- Mounting: Rock or movement indicates wax ring or flange problems
- Flushing: Weak flush may indicate clog, restricted vent, or internal component failure
- Running water: Failed flapper, fill valve, or float mechanism
- Base moisture: Wax ring failure or condensation
Wax ring replacement costs $100-200. Internal component repairs average $50-150.
Water Heaters
Water heater findings include:
- Age and remaining useful life
- Corrosion or rust on tank exterior
- Temperature and pressure relief valve condition
- Combustion air and venting adequacy (gas units)
- Drain pan presence and drainage
- Seismic strapping (in earthquake zones)
See the dedicated water heater guide for detailed evaluation methods.
Fuel Gas Piping Findings
Homes with natural gas or propane have gas piping that connects appliances to the supply. Inspection includes:
Pipe Material and Condition
Gas piping is typically black steel, CSST (corrugated stainless steel tubing), or copper (in some regions).
Common findings:
- Rust or corrosion on black steel pipe
- Improper CSST bonding (electrical grounding)
- Unsupported or inadequately secured lines
- Improper connections or fittings
Gas leaks are detected by odor or with electronic detectors. Any suspected leak requires immediate professional evaluation.
Appliance Connections
Gas appliance connections are inspected for:
- Flexible connector condition and age
- Proper drip leg installation
- Shut-off valve accessibility
- Connector length and routing
Older flexible connectors (pre-1990s brass) should be replaced. Modern stainless steel connectors are safer and more durable.
Related Terms
Key plumbing terminology used in inspection reports:
- DWV: Drain, Waste, and Vent system
- P-trap: Curved pipe section that holds water to block sewer gases
- Shut-off valve: Valve that stops water flow to a fixture or system
- PRV: Pressure-Reducing Valve
- Hose bib: Exterior faucet connection for hoses
- Angle stop: Shut-off valve below sinks and toilets
- TPR valve: Temperature and Pressure Relief valve on water heaters
- Backflow preventer: Device preventing reverse flow into potable water supply
- Cleanout: Access point for clearing drain blockages