Standard rough-in dimensions are the measurements used to position supply and drain lines during framing, before walls are closed. Getting these right prevents costly rework after drywall.
The dimensions below are widely accepted standards for residential rough-in work. Always verify against the fixture manufacturer’s installation instructions and applicable local codes, which may differ.
Toilet Rough-In
Supply
- Height: 6–8 in. above finished floor (AFF), measured to center of supply stub-out
- Horizontal position: 6 in. to the left or right of centerline (away from toilet body)
- Standard connection: 7/8 in. ballcock shank × 3/8 in. OD angle stop outlet
Drain
- Closet flange centerline to finished wall: 12 in. (standard), 10 in. or 14 in. for non-standard fixtures — confirm with fixture spec
- Rough-in height: Flange top should be flush with or slightly above finished floor (1/4 in. max above for tile installations)
Clearances
- 15 in. minimum from centerline to any side obstruction (18 in. preferred per accessibility guidance)
- 21 in. minimum clear space in front of toilet per UPC/IPC (24 in. for ADA)
Lavatory (Bathroom Sink)
Supply
- Height: 19–22 in. AFF to center of stub-outs (varies by vanity height — confirm to manufacturer spec)
- Horizontal spread: 4 in. apart, centered on drain
- Standard hot/cold identification: Hot left, cold right (from user-facing position)
- Connection: 1/2 in. copper stub-out → angle stop → 3/8 in. supply line to faucet
Drain
- Height: 18–20 in. AFF to center of drain stub-out (adjust to actual vanity and trap configuration)
Kitchen Sink
Supply
- Height: 18–22 in. AFF, centered under the sink opening in the cabinet
- Horizontal spread: 8 in. apart, centered on drain
- Connection: 1/2 in. stub-outs → angle stops → supply lines to faucet
Drain
- Height: 16–18 in. AFF for standard 36 in. counter height
- Confirm to dishwasher drain loop requirements if dishwasher is planned
Shower and Tub-Shower
Supply (Pressure-Balancing or Thermostatic Valve)
- Height: 38–48 in. AFF to valve centerline (confirm to valve manufacturer dimensions)
- Horizontal position: Centered on shower opening
- Common configuration: 1/2 in. sweat stub-outs to valve body; follow valve manufacturer’s dimension sheet
Showerhead
- Height: 72–80 in. AFF (standard); 84 in. for rain-style overhead heads
- Standard connection: 1/2 in. FIP drop-ear elbow or integral arm connection
Tub Spout Supply
- Height: 6–8 in. AFF for standard tub spout stub-out
- Connection: 1/2 in. stub-out to tub spout (MIP or slip-fit per fixture spec)
Water Heater Supply
Cold Supply In / Hot Supply Out
- Height: Position based on water heater model’s connection height (typically 3–6 in. above tank top)
- Isolation valves: Full-port ball valve on cold inlet; typically installed 12–18 in. from wall or as accessible as possible
- Standard connection: 3/4 in. NPT connections on most residential tank heaters; use appropriate dielectric unions on installations combining dissimilar metals
Drain Pan and T&P Relief
- T&P relief valve drain: Route to within 6 in. of floor or to drain per code; never terminate in a concealed location
General Notes
- All dimensions are to finished floor unless noted otherwise
- Confirm ADA/accessibility requirements for any accessible unit or applicable jurisdiction
- Stub-out height varies by trim and fixture manufacturer — always request fixture installation sheets before framing
- Local codes may specify different clearances; the dimensions above are reference values based on common UPC and IPC interpretations
Related Resources
For product selection guidance on stop valves, supply lines, and connections used at these rough-in points, visit the Rough-In catalog or contact our team for a product list for your project.