Drain Slope Calculator

Quick slope checks and sizing for residential storm and waste lines. Indicative only — always verify with local standards.

Pipe Diameter

Flow

Pipe Material

Self-Cleansing Threshold (m/s)

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Formulas & Assumptions ▼

Manning Formula: Q = (1/n) * A * R^2/3 * S^1/2

Velocity V = Q / A

Area: A = πD²/4, Hydraulic Radius: R = D/4

Defaults: PVC = 0.011, Concrete/Clay/Cast Iron = 0.013

Disclaimer: These results are indicative only. Always verify with local codes/standards and a licensed professional. No data entered is stored.

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Drain Slope Calculator

Drain Slope Calculator

Formulas & Assumptions ▼

What is Tradify?

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