Installing a horizontal septic tank involves several key steps, starting with preparation and ending with connecting the necessary pipes and installing the drainage field.
Step-by-Step Septic Tank Installation Guide
Based on standard domestic septic tank installation practices, here are the essential steps:
Step 1: Make Sure You Are Prepared
Preparation is crucial before any digging begins. This involves:
- Ensuring you have the correct tank size and type for your property and usage requirements.
- Checking local regulations and obtaining necessary permits for installation.
- Planning the location of the tank and the associated drainage field, considering accessibility for future maintenance.
- Gathering all necessary tools, equipment (like excavators), and materials.
Step 2: Dig the Hole
Excavate the hole for the septic tank. The dimensions should be slightly larger than the tank itself to allow for backfilling and placement of the base material.
- Depth: Sufficient to allow the tank to sit at the required level for pipe connections and ground cover.
- Width/Length: Adequate clearance around the tank sides (typically 300-600mm) for base preparation and backfilling.
- Ensure the base of the excavation is level and stable.
Step 3: Install the Base
A solid, level base is essential for supporting the septic tank and preventing settling or shifting.
- Lay a layer of compacted granular material, such as gravel or sharp sand, at the bottom of the excavated hole.
- The base material should be deep enough to provide adequate support as specified by the tank manufacturer or local regulations (often 150-300mm).
- Compact the base thoroughly to create a firm foundation.
Step 4: Sit the Tank
Carefully lower the horizontal septic tank into the prepared hole and onto the compacted base.
- Use appropriate lifting equipment (e.g., excavator with slings) to handle the tank safely.
- Ensure the tank is level and properly oriented for the inlet and outlet pipe connections.
- Check that the tank sits firmly on the base with no voids underneath.
Step 5: Backfill the Hole
Once the tank is in place, backfill the area around it. This provides stability and secures the tank in the ground.
- Use suitable backfill material, often sand, gravel, or excavated soil free of large rocks or debris that could damage the tank.
- Backfill in layers, compacting each layer evenly around the tank's sides.
- For plastic tanks, it's often recommended to fill the tank partially with water simultaneously with backfilling to equalize pressure and prevent deformation.
Step 6: Install a Septic Drainage Field
A drainage field (also known as a leach field or soakaway) is a critical component of a septic system, dispersing treated effluent into the ground. This step often happens concurrently with or immediately after tank installation.
- Excavate trenches for the drainage field according to design specifications.
- Lay down a layer of gravel or aggregate in the trenches.
- Install perforated distribution pipes on top of the gravel.
- Cover the pipes and gravel with geo-textile fabric and then backfill the trenches with soil.
Step 7: Connect the Pipes
Connect the inlet pipe from the property's plumbing system to the septic tank's inlet, and the outlet pipe from the tank to the drainage field distribution system.
- Ensure pipes are correctly sized and sloped to allow gravity flow.
- Use appropriate seals and connectors to create watertight joints.
- Install access risers and lids over the tank's compartments for future inspection and pumping.
Following these steps, informed by standard septic tank installation guide principles, is essential for a safe, effective, and long-lasting septic system.
