सेप्टिक टैंक एक भूमिगत, पानी-रोधी कंटेनर है जो घरेलू अपशिष्ट जल को जमा करके और उसका प्राथमिक उपचार करता है। यह एक प्रकार का छोटा सीवेज उपचार संयंत्र है जो ग्रामीण क्षेत्रों में और उन घरों में प्रयोग किया जाता है जहाँ सीवर नेटवर्क नहीं है. सेप्टिक टैंक आमतौर पर कंक्रीट, फाइबरग्लास या पॉलीइथिलीन से बने होते हैं. 

IS 2470: 1985

 It is divided into two parts:

Part 1 deals with design criteria and construction,

Part 2 focuses on secondary treatment and disposal of septic tank effluent. 

I. Site Selection and Planning:

II. Tank Design and Materials:

III. Construction Practices:

I. Site Selection and Planning:

·         Suitable Location:

·         Downhill from the house and away from water sources (well, etc.). 

·         At least 15m (50ft) from the nearest water supply. 

·         3m (10ft) from the nearest building. 

·         Avoid areas prone to flooding or where vehicles might drive over the tank. 

              Draw a Plan:

·         Show the septic tank's location relative to the house, property lines, and water sources. 

·         Include ground slope and any other relevant features. 

              Soil Testing:

·         Determine the soil type and permeability for proper drainfield design. 

              Permeability Test:

·         Test the soil's ability to absorb water to ensure proper effluent drainage. 

II. Tank Design and Materials:

·         Tank Capacity:

·         Calculate the required tank volume based on daily water usage and sludge storage. 

·         Ensure adequate sludge and scum storage. 

              Two Compartments:

·         The primary compartment should be larger than the secondary. 

·         Partition wall with an opening between compartments. 

              Inlet and Outlet Pipes:

·         Use T-pipes to avoid solids entering the drainfield. 

·         Ensure proper venting of the septic tank. 

              Tank Material:

·         Use reinforced concrete, concrete blocks, or other suitable materials. 

·         Ensure the tank is watertight and structurally sound. 

              Sewer Line:

·         Use non-corrosive, hardwearing material like concrete or plastic. 

·         Ensure proper slope and grade for wastewater flow. 

III. Construction Practices:

·         Digging and Excavation:

o    Ensure proper depth and size for the tank and drainfield. 

·         Concrete Pouring:

o    Use high-quality concrete mix and ensure proper curing. 

·         Tank Installation:

o    Follow design specifications for placement and connections. 

·         Drainfield Installation:

o    Ensure proper spacing and depth of perforated pipes. 

·         Vent Pipe Installation:

o    Extend vent pipe above the roof to allow for gas escape. 

·         Testing and Inspection:

o    Conduct a watertightness test and ensure proper connections. 

o    Inspect for leaks or damage during construction. 

IV. Maintenance and Monitoring:

·         Sludge Pumping:

o    Regularly pump out sludge to maintain tank capacity.

·         Drainfield Inspection:

o    Monitor for signs of clogging or failure.

·         Vent Pipe Inspection:

o    Ensure the vent pipe is free of obstructions. 

V. Safety and Compliance:

·         Local Codes and Regulations:

o    Adhere to all local and state regulations for septic systems.

·         Permits:

o    Obtain necessary permits before starting construction.

·         Safety Precautions:

o    Take necessary safety precautions during construction and maintenance.