📌 Introduction
Designing a proper sanitation system requires accurate septic tank size calculation and correct layout of the soak pit system. For engineers and contractors, having ready-made septic tank CAD drawings and soak pit DWG files along with a working size calculator can save significant time.
👉 In this guide, you will get:
✔ Septic tank CAD file download
✔ Soak pit DWG drawing
✔ Septic tank size calculator (Rectangular + Circular)
✔ Design guidelines based on Indian standards
✔ Practical examples
📥 Download Septic Tank & Soak Pit CAD Files
Septic Tank and Soak Pit CAD File Download (DWG) 175.33 KB 38 downloads
🚰 Septic Tank Size Calculator Number of Users: Water Usage (Litres per person): Retention...🧱 What is a Septic Tank?
A septic tank is an underground wastewater treatment structure used in buildings without sewer connection. It separates solids and liquids and allows wastewater to flow into a soak pit.
🕳️ What is a Soak Pit?
A soak pit is a porous underground chamber filled with stones that allows treated wastewater to infiltrate into the soil.
📏 Septic Tank Size Calculation (India)
📌 Standard Rule:
👉 120–150 Litres per person per day
🧮 Septic Tank Size Calculator (RECTANGULAR & CIRCULAR)
🚰 Septic Tank Size Calculator
📊 Septic Tank Size Chart
| Users | Tank Size (m³) |
|---|---|
| 5 | 1.5–2.0 |
| 10 | 3.0–4.0 |
| 20 | 6.0–8.0 |
🏗️ Design Guidelines (India)
📌 Key Points:
✔ Minimum depth: 1.2–1.5 m
✔ Provide baffle wall
✔ Maintain 30m distance from water source
✔ Vent pipe required
✔ Use RCC or brick masonry
FAQ
What is standard size of septic tank?
Depends on users, typically 2–4 m³ for small houses.
How do you calculate septic tank size?
Volume = Users × Water usage × Retention time
What is soak pit size?
Usually 1–2 m diameter and 2–3 m deep.
Which shape is better rectangular or circular?
Rectangular is common; circular is structurally stronger.
📢 Why Download from MEPWORK?
- Free DWG files
- Ready-to-use drawings
- Designed for engineers
- Updated as per industry standards
MEPWORK.IN is developed by an MEP engineering professional with hands-on experience in building services design and execution.
The platform is created to solve real-world engineering problems and provide practical tools for faster and more accurate project work.
Download free AutoCAD DWG files for MEP engineers including plumbing, HVAC, fire alarm, and electrical systems.
All drawings are ready to use and based on industry standards.
All resources are regularly updated as per latest standards (NBC 2016, IS Codes, NFPA, and 2026 industry practices).





















