📐 Slope Calculator

📚 Plumbing Code Requirements

Proper slope is critical for drainage systems to function correctly. Too little slope causes slow drainage and buildup; too much causes liquids to outrun solids.

Pipe Diameter	Minimum Slope	Maximum Slope	Notes
1.5"	1/4" per ft (2%)	1/2" per ft (4%)	Generally not allowed in buildings
2"	1/4" per ft (2%)	1/2" per ft (4%)	For fixture drains only
3"	1/8" per ft (1%)	1/2" per ft (4%)	Minimum for building drains
4"	1/8" per ft (1%)	1/2" per ft (4%)	Standard for building drains
6"+	1/16" per ft (0.5%)	1/2" per ft (4%)	Large diameter sewers

⚡ Key Principles

• IPC (International Plumbing Code): 1/8" per foot minimum for 3" and larger
• UPC (Uniform Plumbing Code): 1/4" per foot minimum for 4" and smaller
• Maximum slope: Generally 1/2" per foot to prevent liquids outrunning solids
• Cleanouts: Required at intervals based on pipe size

⚠️ Important Considerations

• Slope must be consistent - no dips or sags where waste can accumulate
• Consider total drop vs. length when planning grades
• In areas with frozen ground concerns, burial depth may need adjustment
• Always verify with local code requirements - some jurisdictions modify codes