TopTank 1000L Underground Spherical Tank

TopTank 1000L Spherical Tank

The TopTank 1000L Underground Tank is a high-density polyethylene storage vessel designed for discrete, subsurface water management in residential and commercial projects. This spherical unit utilizes advanced rotational molding to ensure a seamless finish, providing high structural integrity for long-term burial. It serves as a primary reservoir for rainwater harvesting, borehole backup, or municipal water buffering where surface space is restricted.

Built for the Job

Plumbers and site supervisors specify this spherical vessel for its superior load-bearing geometry. Unlike vertical tanks, the round profile distributes external soil pressure and hydrostatic forces evenly across the entire surface area, reducing the risk of wall deformation or stress cracking. This makes the unit particularly effective in areas with shifting soil conditions or high water tables. The compact footprint allows for installation in narrow alleyways or beneath landscaped areas, maintaining the aesthetic profile of the property while securing a 1000-litre reserve.

• Subsurface rainwater collection for irrigation and greywater systems.

• Potable water storage for sites with limited above-ground footprint.

• Buffer tank installation for low-pressure municipal supply lines.

Product Highlights

Structural Integrity

The spherical design and integrated ribbing provide maximum resistance against earth loads and buoyancy.

Material Performance

• Manufactured from 100% food-grade polyethylene for safe water storage.
• Chemical-resistant body prevents corrosion from acidic or alkaline soil.

Technical Specifications

What’s Included

• 1 x 1000L Spherical Polyethylene Tank Body

• 1 x Heavy-Duty Lockable Manhole Cover

• 1 x Internal Inlet Pipe Seal

On-Site & Workshop Notes

• Always install the storage unit on a 100mm level bed of compacted sand to prevent point loading from sharp rocks.

• Backfill the excavation with clean sand or pea gravel in 150mm layers, tamping manually to ensure even support around the circumference.

• This subsurface container must be vented to the atmosphere to prevent vacuum collapse during high-flow pumping operations.

• Ensure the manhole cover remains accessible for periodic cleaning and inspection of the internal float valves or pumps.