AtlantisTanks Group LTD

Atlantis modular cellular tanks are used to build underground attenuation systems, soakaways and rainwater harvesting stores. The interlocking plastic crates create a strong, void-heavy structure that can be wrapped for attenuation (temporary storage before controlled discharge) or left permeable for infiltration into surrounding ground. They're widely specified on housing and commercial developments to manage surface water run-off in line with SuDS requirements.

Both use the same crates, but the geotextile wrap differs. An attenuation tank is fully lined with an impermeable membrane so water is held back and released slowly through a flow control device into a sewer or watercourse. A soakaway uses a permeable geotextile that allows water to infiltrate directly into the surrounding subsoil, so it only works where ground conditions and percolation tests allow it.

Sizing depends on the contributing catchment area, local rainfall intensity, the discharge rate agreed with the water authority or drainage engineer, and the storage volume required to attenuate a 1-in-100-year storm plus climate change allowance. Most projects need a drainage calculation carried out by a suitably qualified engineer rather than a rule-of-thumb figure. We can advise on crate quantities once you have your required storage volume in cubic metres.

Atlantis crates are engineered for a range of burial depths and are rated for pedestrian, light traffic or full highway loading depending on the product line and cover depth used above the structure. Installation depth and loading capacity must be checked against the manufacturer's design tables, as backfill material, compaction and any surface loading all affect performance. Get the specification confirmed before ordering if the system sits under a driveway or access road.

Yes — the geotextile wrap is a fundamental part of the system, not an optional extra. Use a permeable, non-woven geotextile for soakaways to allow infiltration while filtering out fines, and an impermeable liner for attenuation systems where water must be contained and controlled. Getting the wrong type or a poor overlap/seal at joints is one of the most common causes of failure, so follow the installation guide closely.

Surface water attenuation and soakaway systems generally fall under Building Regulations Part H (drainage) and often need sign-off from the local authority or water company, particularly where discharge is to a public sewer or watercourse. Many developments also require SuDS approval as a planning condition. It's worth confirming requirements with your local authority or drainage engineer before installation, especially for anything other than a small domestic soakaway.