Horizontal septic tanks

Marsh Industries’ horizontal septic tanks are available in capacities ranging from 2800 – 20,000+ litres.

Horizontal septic tanks provide settlement and some biological treatment to raw domestic sewage (wastewater), however the domestic wastewater is not fully treated and must receive additional treatment before discharge to the water environment – the most common method being to spread the waste to land via an underground drainage field.

As an optional extra, Marsh can supply horizontal septic tanks with a unique Polylok filter that is designed to further reduce suspended solids by up to 40% – prolonging system efficiency and drainage field life.

CE ApprovedCE ACCREDITED
Providing an impressive hydraulic efficiency of 99.63%
Tested and approved at PIA GmbH, Aachen, Germany

Note: Following British Water regulations for domestic applications, the minimum storage capacity is 2700 litres for a standard four-person dwelling. Following this, each additional user will require an additional 150 litres of storage capacity.

Marsh horizontal septic tanks

Normally the simplest and most economical means of treating wastewater from small developments, a septic tank holds sewage and allows solids to settle into sludge at the bottom of the tank. Here it is naturally broken down by a process known as anaerobic digestion, which provides settlement and some biological treatment. The effluent is not fully treated and must receive additional treatment before discharge to the water environment – the most common method being to spread the effluent to land via an underground drainage field.

  • Tested to BSEN12566:1 and CE-marked to ensure compliance with latest environmental and Building Regulations requirements
  • Provides an outstanding 99.63% hydraulic efficiency
  • Unique Polylok filter improves effluent quality and prolongs drainage field life (Euro:Septic units only)
  • Traditional ‘onion-style’ tanks for standard installations
  • Low profile versions for high water table or hard rock site conditions
  • Heavy duty shell as standard to enable installation in all ground conditions
  • Integral lifting eyes for improved on-site handling
  • ‘Keying-in’ assists anchoring into granular or concrete surround
  • Pedestrian cover included as standard

Size Length Width Height Inlet invert Inlet dia Outlet invert Outlet dia
2800L 3000 1250 1750 500 110 800 110
3800L 4000 1250 1750 500 110 800 110
4500L 2650 1600 2100 500 110 800 110
6000L 2950 1900 2400 500 160 800 160
8000L 3640 1900 2400 500 160 800 160
10000L 4200 1900 2400 500 160 800 160
12000L 5200 1900 2400 500 160 800 160
14000L 5840 1900 2400 500 160 800 160
16000L 6700 1900 2400 500 160 800 160
18000L 7500 1900 2400 500 160 800 160
20000L 8100 1900 2400 500 160 800 160

For precise tank sizes and configurations, please contact Marsh Industries
All dimensions in mm


Marsh Euro:Septic leaflet

Marsh domestic brochure

Horizontal Septic tank
CE Certificate