| No. | Term | Definition |
|---|---|---|
| 1. | ABS pipe | Black plastic drain pipe material. |
| 2. | Adapter | Fitting joining different pipe sizes or types. |
| 3. | Air admittance valve | One-way vent valve; admits air, blocks sewer gas. |
| 4. | Angle stop | Shutoff valve under sinks and toilets. |
| 5. | Anode rod | Sacrificial rod preventing water heater corrosion. |
| 6. | Anti-siphon valve | Prevents backflow by stopping siphon action. |
| 7. | Backflow | Reverse flow contaminating potable water. |
| 8. | Backflow preventer | Device stopping reverse flow into supply. |
| 9. | Ball valve | Quarter-turn shutoff valve with ball. |
| 10. | Barbed fitting | Fitting for flexible tubing with ridges. |
| 11. | Basin wrench | Tool for tightening faucet nuts. |
| 12. | Bell trap | Floor drain trap with removable bell. |
| 13. | Black iron pipe | Steel pipe used for gas lines. |
| 14. | Blowout plug | Plug sealing drain line for testing. |
| 15. | Booster pump | Pump increasing water pressure. |
| 16. | Branch drain | Horizontal drain serving multiple fixtures. |
| 17. | Brass nipple | Short threaded brass pipe section. |
| 18. | Cleanout | Access opening for clearing drain blockages. |
| 19. | Code | Regulations governing plumbing installation and safety. |
| 20. | Compression fitting | Seal using ferrule tightened by nut. |
| 21. | CPVC | Chlorinated PVC for hot and cold water. |
| 22. | Cross-connection | Link between potable and nonpotable systems. |
| 23. | Dielectric union | Fitting preventing galvanic corrosion between metals. |
| 24. | Dip tube | Directs cold water to tank bottom. |
| 25. | Drain snake | Flexible auger for clearing clogs. |
| 26. | Drainage slope | Pitch ensuring proper gravity flow. |
| 27. | DWV | Drain, waste, and vent system. |
| 28. | Eductor jet | Venturi nozzle in some pumps. |
| 29. | Effluent | Liquid wastewater leaving a system. |
| 30. | Elbow | Angle fitting changing pipe direction. |
| 31. | Escutcheon | Decorative cover plate around pipe penetration. |
| 32. | Expansion tank | Absorbs thermal expansion in closed systems. |
| 33. | Fernco coupling | Rubber coupling with clamps for repairs. |
| 34. | Fixture unit (FU) | Load measure for plumbing system sizing. |
| 35. | Flange | Rim fitting; toilet flange mounts toilet. |
| 36. | Float valve | Valve controlled by float level. |
| 37. | Flow rate (GPM) | Water volume delivered per minute. |
| 38. | Flushometer | Valve for commercial toilet or urinal flushing. |
| 39. | Frost-free sillcock | Outdoor faucet designed to resist freezing. |
| 40. | Gate valve | Multi-turn valve with rising gate. |
| 41. | GFCI | Shock-protection electrical outlet near water. |
| 42. | Grease trap | Interceptor capturing fats, oils, and grease. |
| 43. | Hammer arrestor | Device reducing water hammer shock. |
| 44. | Hanger | Support bracket securing pipe runs. |
| 45. | Heat trap | Check fitting reducing water heater heat loss. |
| 46. | Hose bibb | Exterior faucet with hose threads. |
| 47. | Hub | Socket end of cast-iron fitting. |
| 48. | Hydrostatic test | Pressure test using water. |
| 49. | Impeller | Rotating pump part moving water. |
| 50. | Interceptor | Device separating solids or grease from waste. |
| 51. | Isolation valve | Valve shutting off a section for service. |
| 52. | J-trap | Curved trap under sinks preventing sewer gas. |
| 53. | Jet pump | Pump using jet assembly to lift water. |
| 54. | Joint compound | Pipe dope sealing threaded connections. |
| 55. | Key stop | Recessed shutoff operated with a key. |
| 56. | Kitchen sink strainer | Basket fitting connecting sink to drain. |
| 57. | Knife valve | Sliding gate valve for wastewater. |
| 58. | Lacquer thinner | Solvent used for cleaning some surfaces. |
| 59. | Lavatory | Bathroom sink fixture. |
| 60. | Lead-free | Meets limits for lead in wetted parts. |
| 61. | Leak detector | Sensor identifying water leaks. |
| 62. | Main shutoff | Primary valve stopping building water supply. |
| 63. | Manifold | Header distributing water to multiple lines. |
| 64. | Meter coupling | Fitting connecting to water meter. |
| 65. | Mixing valve | Blends hot and cold to set temperature. |
| 66. | Nipple extractor | Tool removing broken threaded pipe. |
| 67. | No-hub coupling | Shielded coupling for cast-iron DWV. |
| 68. | Nominal size | Named pipe size, not exact measurement. |
| 69. | NSF/ANSI 61 | Standard for potable water contact materials. |
| 70. | O-ring | Rubber seal ring for joints. |
| 71. | Offset flange | Toilet flange shifting centerline slightly. |
| 72. | Overflow | Secondary outlet preventing fixture overfilling. |
| 73. | P-trap | U-shaped trap blocking sewer gases. |
| 74. | PEX | Flexible cross-linked polyethylene water tubing. |
| 75. | Pipe cutter | Tool cutting copper or plastic pipe. |
| 76. | Pipe dope | Thread sealant compound for fittings. |
| 77. | Plumber’s putty | Malleable sealant for drains and fixtures. |
| 78. | Pressure regulator | Valve reducing incoming water pressure. |
| 79. | PRV | Pressure-reducing valve; controls supply pressure. |
| 80. | Pump check valve | Prevents pumped water from flowing backward. |
| 81. | Quick-connect fitting | Push-fit connector for tubing. |
| 82. | Reducer bushing | Threaded fitting reducing pipe size. |
| 83. | Relief valve (T&P) | Safety valve releasing excess temperature or pressure. |
| 84. | Riser | Vertical pipe section. |
| 85. | Rough-in | Initial installation of concealed piping and drains. |
| 86. | Saddle valve | Clamp-on piercing valve; often discouraged. |
| 87. | Sanitary tee | T-fitting directing waste into vertical drain. |
| 88. | Septic tank | Onsite wastewater treatment and settling tank. |
| 89. | Sillcock | Outdoor faucet assembly. |
| 90. | Slip joint | Tubular drain joint tightened by nut. |
| 91. | Solder | Metal alloy used to join copper pipe. |
| 92. | Solvent cement | Adhesive fusing PVC/ABS joints. |
| 93. | Stopper | Plug closing a drain opening. |
| 94. | Strainer | Screen catching debris in drains. |
| 95. | Sump pump | Pump removing groundwater from a sump pit. |
| 96. | Teflon tape | PTFE thread tape for sealing. |
| 97. | Tempering valve | Mixing valve limiting hot water temperature. |
| 98. | Trap primer | Adds water to traps to prevent drying. |
| 99. | Union | Detachable fitting allowing easy disassembly. |
| 100. | Vacuum breaker | Prevents backsiphonage at hose connections. |