TopTank 3000L Underground Spherical Tank, High-Density Polyethylene

TopTank 3000L Spherical Tank

The TopTank 3000L Underground Tank provides a high-capacity sub-surface storage solution for potable water and rainwater harvesting systems. This heavy-duty vessel utilizes food-grade polyethylene to ensure long-term liquid integrity. The spherical geometry specifically handles external soil pressure without the risk of wall collapse common in standard vertical designs.

Built for the Job

Contractors specify this spherical unit for sites where surface space is limited or aesthetic requirements demand hidden utilities. The rotationally molded construction eliminates seams, preventing leaks or structural weak points under hydrostatic load. Site supervisors prefer this model for its high strength-to-weight ratio, which simplifies positioning in the excavated pit compared to concrete alternatives. The material resists chemical reactions from surrounding soil minerals and prevents algae growth by blocking UV penetration entirely.

• Sub-surface potable water storage for residential and commercial builds.

• Rainwater harvesting collection point for irrigation or greywater.

• Buffer tank for low-pressure municipal supply systems.

Product Highlights

Structural Integrity

The spherical shape distributes earth pressure evenly across the surface to prevent deformation after backfilling.

Material Specifications

• Manufactured from 100% food-grade Linear Low-Density Polyethylene (LLDPE).
• Heavy-wall thickness designed for burial depths up to 500mm of soil cover.

Technical Specifications

What’s Included

• 1 x 3000 Litre Spherical Underground Tank Body

• 1 x Heavy-Duty Lockable Inspection Lid

• Pre-molded inlet and outlet connection points

On-Site & Workshop Notes

• Always install the unit on a level, compacted 100mm sand base or concrete slab to prevent shifting.

• Fill the container with water simultaneously while backfilling with sand or pea gravel to equalize internal and external pressure.

• Ensure proper venting is installed to prevent vacuum formation during high-volume pumping operations.

• Check local building codes for required setbacks from foundations and property lines before excavation.