Helonic is an AI construction drawing analysis platform for teams researching plumbing plan symbols during drawing review. Complete reference for pipe types, fixtures, valves, and fittings on plumbing drawings
Plumbing plans show pipes as single lines with labels (CW, HW, S, etc.). Pipe sizes are typically shown as diameter (e.g., 2" CW). Slope is indicated for drainage lines (e.g., 1/4"/ft). Understanding line weights helps distinguish between different pipe systems on drawings.
| Symbol | Meaning | Notes |
|---|---|---|
| , , CW, , | Cold Water | Often blue on colored drawings |
| , , HW, , | Hot Water | Often red on colored drawings |
| , , HWR, , | Hot Water Return | Recirculation line |
| , , S, , | Sanitary Sewer | Waste line to sewer |
| , , V, , | Vent | Venting for drainage |
| , , SD, , | Storm Drain | Roof/site drainage |
| , , G, , | Gas | Natural gas supply |
| , , FP, , | Fire Protection | Sprinkler supply |
| Symbol | Meaning | Notes |
|---|---|---|
| ◯ | Floor Drain | Circle with drain indication |
| ◻ | Water Closet (Toilet) | Rectangular outline with tank |
| ▭ | Urinal | Wall-mounted fixture |
| ◠ | Lavatory (Sink) | Semi-circle or oval |
| ▢ | Kitchen Sink | Rectangle, often double bowl |
| ⌓ | Shower | Square with drain |
| □ | Bathtub | Rectangle with drain end marked |
| ⊕ | Cleanout | Circle with cross |
| Symbol | Meaning | Notes |
|---|---|---|
| ⊗ | Gate Valve | Full bore shutoff |
| ◇ | Globe Valve | Throttling/control valve |
| ⊘ | Ball Valve | Quarter-turn shutoff |
| ◈ | Check Valve | Prevents backflow |
| ▷ | Pressure Reducing Valve | PRV - reduces water pressure |
| △ | Backflow Preventer | BFP - prevents contamination |
| ⊙ | Pressure Gauge | Monitors system pressure |
| Symbol | Meaning | Notes |
|---|---|---|
| □WH | Water Heater | Tank or tankless |
| □P | Pump | Circulation or booster |
| ▣ | Grease Interceptor | Kitchen waste treatment |
| ⬡ | Expansion Tank | Thermal expansion control |
| ◻HB | Hose Bibb | Exterior faucet |
| ⊞ | Water Meter | Utility metering point |
| Symbol | Meaning | Notes |
|---|---|---|
| ├ | Tee | Branch connection |
| ┼ | Cross | Four-way connection |
| ∟ | 90° Elbow | Direction change |
| ∠ | 45° Elbow | Gradual direction change |
| ◇ | Reducer | Pipe size change |
| ⊐ | Cap | End of line |
| ⊥ | Union | Removable connection |
P sheets use CW, HW, SAN, VTR, and similar abbreviations that must match the plumbing legend.
Related references for plumbing and MEP drawing review.