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Fixtures

Toilet

An oval shape (the bowl) attached to a smaller rectangle or circle (the tank) against the wall. Requires a 12-inch rough-in from the wall and at least 30 inches of side-to-side clearance.

Also: water closet, WC, commode

Found in: Bathrooms, powder rooms, half baths

Bathtub

A large rectangle (typically 60 by 30 inches or 60 by 32 inches) with rounded corners at one end. A small circle indicates the drain location. Drawn against one or more walls.

Also: tub, bath, soaking tub

Found in: Bathrooms, master baths, guest bathrooms

Shower

A square or rectangle (typically 36 by 36 inches minimum) with a small circle indicating the drain and lines or dots representing the shower head. Drawn with a threshold line at the opening.

Also: shower stall, shower enclosure, walk-in shower

Found in: Bathrooms, master baths, gym facilities

Bathroom Sink

A small rectangle with a single oval basin inside, typically set into a vanity counter shown as a longer rectangle along the wall. A circle represents the faucet.

Also: lavatory, lav, wash basin, vanity sink

Found in: Bathrooms, powder rooms, vanity counters

Kitchen Sink

A larger rectangle with one or two oval basins inside, set into the countertop line. Usually 33 to 36 inches wide with a faucet circle centered above.

Also: kitchen basin, double bowl sink

Found in: Kitchen countertops, kitchen islands, butler's pantries

Utility Sink

A deep, square basin (approximately 24 by 24 inches) drawn as a simple rectangle with one large basin. Often mounted on legs rather than in a counter.

Also: laundry sink, slop sink, mop sink, service sink

Found in: Laundry rooms, garages, utility rooms, workshops

Equipment & Connections

Water Heater

A circle (for tank-style, approximately 20 inches diameter) or a small rectangle (for tankless), labeled WH. Supply and return lines connect to it.

Also: hot water heater, HWH, water tank

Found in: Utility rooms, garages, basements, mechanical closets

Floor Drain

A small circle or square with an X inside, placed in the floor area. Indicates a drain set flush into the floor for collecting water runoff.

Also: FD, area drain

Found in: Garages, basements, laundry rooms, mechanical rooms, shower areas

Cleanout

A circle with the letters CO, placed along drain lines at access points. Provides a removable cap for snaking or clearing drain blockages.

Also: CO, drain cleanout, sewer cleanout

Found in: Near foundation walls, at changes in drain direction, exterior of building

Hose Bib

A small triangle or circle on the exterior wall with the letters HB, representing an outdoor faucet connection for garden hoses.

Also: outdoor faucet, sillcock, spigot, hose faucet

Found in: Exterior walls, near gardens, driveways, garage sides

Washing Machine Hookup

A small box with supply valves (hot and cold lines) and a drain connection, labeled WM or shown with standard laundry symbols. Indicates pre-plumbed connection for a washer.

Also: washer hookup, laundry hookup, washer connection

Found in: Laundry rooms, laundry closets, utility rooms, garages

How to Read Plumbing Floor Plan Symbols

Plumbing symbols are drawn as simplified overhead views of the fixtures. A toilet is one of the easiest to recognize — it looks like an oval (the bowl) attached to a rectangle or circle (the tank). Sinks are shown as rectangles with oval basins inside, similar to kitchen sinks but smaller. Bathtubs appear as large rectangles with rounded corners at one end.

When reading plumbing plans, look for the supply and drain lines. Supply lines (bringing clean water in) are typically drawn as solid lines, while drain/waste/vent (DWV) lines are drawn as dashed lines or thicker lines. Hot water lines may be marked differently from cold — often with an H and C label or different line patterns.

Fixture placement is driven by plumbing efficiency. Bathrooms, kitchens, and laundry rooms are often stacked on multiple floors or placed back-to-back so they can share plumbing walls (called wet walls). If you see bathrooms on opposite sides of the same wall, that is intentional plumbing economy. The water heater is typically placed centrally to minimize the distance hot water has to travel.

Look for cleanout symbols near the foundation or at changes in drain direction — these are access points for clearing clogs. Floor drains are shown in utility areas, garages, and basements. Hose bibs (outdoor faucets) are drawn on exterior walls. Washing machine hookups are shown as a small box with supply and drain connections, typically in a laundry room or closet.

Common Mistakes

A common mistake is confusing bathroom sinks with kitchen sinks — bathroom sinks are smaller and shown in vanity counters or as pedestal shapes. People also fail to notice the water heater location, which affects how long it takes for hot water to reach distant fixtures. Another error is ignoring drain slope requirements — all drains must slope downward to the main sewer line, which limits where you can add plumbing on lower floors.

Pro Tips

• Fixtures that share a wall (back-to-back bathrooms) save on plumbing costs — look for this efficient layout.
• Check that the water heater is centrally located to minimize hot water wait times at distant fixtures.
• Floor drains need to be at the lowest point in the room — verify slopes on garage and basement plans.

Related Symbol Categories