Water Distribution Systems
Supply pipe materials, sizing methods, water velocity, friction loss, pressure calculations, and pipe support spacing.
- Identify approved water supply pipe materials and their applications
- Size water distribution piping using WSFU values and Hunter's curve
- Calculate pressure losses from static head and friction
- State water velocity limits and pipe support spacing requirements
- Explain water hammer arrestors and pressure reducing valves
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Supply Pipe Materials - Copper, PEX & CPVC
Approved Materials
Water supply piping must be made of materials approved by the plumbing code for potable water service. The three most commonly used residential water supply pipe materials are copper, PEX, and CPVC.
Copper
Types: Type L (general), Type M (light), Type K (heavy)
Joining: Soldering, brazing, press fittings
Pros: Long life, fire-resistant, proven reliability
Cons: Higher material cost, requires skilled labor
PEX (Cross-Linked Polyethylene)
Types: PEX-A, PEX-B, PEX-C
Joining: Crimp, clamp, expansion fittings
Pros: Flexible, freeze-resistant, fast installation
Cons: Cannot be exposed to UV, not for outdoor use
CPVC (Chlorinated PVC)
Types: CTS (copper tube size)
Joining: Solvent welding
Pros: Resistant to chlorinated water, easy installation
Cons: Brittle if struck, temperature limits
Minimum Pipe Sizes
The minimum water service pipe size for a single-family residence is 3/4 inch. This is the pipe from the water main to the building. Individual fixture supply pipes may be smaller (typically 1/2 inch minimum), but the main service line must be at least 3/4 inch.
The minimum hot water supply pipe size to a fixture is 1/2 inch for most fixtures per code.
Copper, PEX, and CPVC are the primary residential supply pipe materials. The minimum water service pipe for a single-family residence is 3/4 inch, and minimum hot water supply to fixtures is 1/2 inch.