Plumbing Basics Cheat Sheet

Pipe sizes, materials, fittings, and drainage requirements for residential plumbing. Great foundation for DIY plumbing repairs and installations.

Pipe Sizes & Applications
SizeMaterialCommon Uses
1/2"PEX, CopperSupply lines to fixtures
3/4"PEX, CopperMain water lines, multiple fixtures
1"PEX, CopperService entrance, manifolds
1-1/4"PVC, ABSSink drains
1-1/2"PVC, ABSBathtub, shower drains
2"PVC, ABSWashing machine, branch drains
3"PVC, ABS, Cast IronToilet drains, main stacks
4"PVC, ABS, Cast IronMain sewer line, stacks
Pipe Materials

PEX (Cross-linked Polyethylene)

  • Flexible, easy to install
  • Freeze-resistant
  • Not for outdoor use (UV sensitive)
  • Requires special tools and fittings

Copper

  • Types: M (thin), L (standard), K (thick)
  • Durable, heat-resistant
  • Requires soldering or compression fittings
  • Can corrode in acidic water

PVC (Polyvinyl Chloride)

  • White pipe for cold water drains
  • Not for hot water
  • Glued with PVC cement
  • Inexpensive, easy to work with

ABS (Acrylonitrile Butadiene Styrene)

  • Black pipe for drains
  • Similar to PVC, more flexible
  • One-step cement (no primer)
  • Not allowed in all areas
Drainage & Venting

DWV Slope Requirements

  • Minimum slope: 1/4" per foot
  • Maximum slope: 3" per foot (to prevent siphoning)
  • Check slope with level before securing

Vent Requirements

  • Every fixture needs a vent
  • Vent must slope upward from drain
  • Minimum vent size: 1-1/4" (often 2")
  • Vents must extend through roof or tie to existing vent

Trap Requirements

  • P-trap for sinks, showers, tubs
  • Toilets have built-in trap
  • Trap arm: max 2x pipe diameter from trap to vent
  • Keep traps accessible for cleaning
Water Pressure & Flow

Normal Pressure: 40-60 PSI

Maximum: 80 PSI (PRV required above)

Minimum: 30 PSI (fixtures may not work properly)

Flow Rates:

  • Shower: 2.5 GPM
  • Faucet: 2.2 GPM
  • Toilet: 1.6 GPF (gallons per flush)
  • Dishwasher: 1-2 GPM
  • Washing Machine: 2-3 GPM
Common Fittings

90° Elbow

Right angle turn

45° Elbow

Gentler angle turn

Coupling

Join two straight pipes

Tee

Three-way connection

Wye

45° branch connection

Reducer

Change pipe size

Cap

Close end of pipe

Union

Removable connection

Soldering Copper Pipe
  1. Cut pipe square with tube cutter
  2. Deburr inside and outside of pipe
  3. Clean pipe and fitting with emery cloth or wire brush
  4. Apply flux to pipe end and inside fitting
  5. Assemble joint and wipe excess flux
  6. Heat joint evenly with torch until flux bubbles
  7. Touch solder to joint (not torch flame)
  8. Solder should flow into joint by capillary action
  9. Remove heat when solder ring appears
  10. Let cool naturally, wipe excess solder
Emergency Shutoffs
  • Main Shutoff: Usually near water meter or where service enters
  • Fixture Shutoffs: Under sinks and toilets (angle stops)
  • Water Heater: Cold water inlet valve at top of tank
  • Outdoor Hose Bibs: Interior shutoff valve to prevent freezing
  • Know locations before emergency occurs
  • Test valves annually to ensure they work

Additional Information

About This Plumbing Basics Guide

This plumbing basics cheat sheet provides essential reference information for DIY homeowners tackling common plumbing projects. From understanding pipe sizes and materials to proper drain slope requirements, this guide covers the fundamental knowledge you need for successful plumbing repairs and installations.

Whether you're replacing a faucet, fixing a leaky pipe, installing a new toilet, or planning a bathroom renovation, understanding plumbing basics helps you work more efficiently and avoid costly mistakes. This reference includes pipe sizing for supply and drain lines, material selection guidance, soldering techniques, and critical venting requirements that ensure your plumbing system functions properly.

Plumbing work requires attention to detail and adherence to local codes. While many homeowners can successfully handle basic repairs, complex projects involving main drain lines, water heaters, or gas piping should be left to licensed professionals. Always check local building codes and permit requirements before starting any significant plumbing project.

Why Use This Plumbing Reference Guide?

Having quick access to plumbing specifications helps ensure your projects function properly and meet code requirements. This guide saves time at the hardware store and helps prevent water damage from improper installations.

  • Quickly identify the correct pipe size for any fixture or application
  • Choose the right pipe material (PEX, copper, PVC, ABS) for your project
  • Ensure proper drain slope to prevent clogs and sewer gas issues
  • Understand venting requirements that keep your drains flowing properly
  • Learn proper soldering techniques for leak-free copper joints
  • Know where your emergency shutoffs are located before problems occur
Frequently Asked Questions

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