drainmax tunnel
DRAINMAX tunnels trenches can be flushed to eliminate sediment that renders other solutions ineffective.



Long term efficient infiltration and storm water run-off reduction, for minimum space.

DRAINMAX tunnel infiltration trench is a user-friendly solution certified for long term efficient infiltration and attenuation of stormwater.
Its tunnel geometry with rigid construction of recyclable HDPE plastic ensures vehicle loading capacity up to 66 tons. DRAINMAX creates significant void space underground which makes it very space efficient to capture, infiltrate and attenuate stormwater.

drainmax product image

The clever design of the DRAINMAX system guarantees a constant level of efficient infiltration in the long run. The walls and bottom of the DRAINMAX tunnel trench can be completely flushed periodically to eliminate the problem many other solutions have, which is sediment accumulation that renders them eventually ineffective.


The DRAINMAX Tunnel infiltration trench is produced by one of the largest and most advanced thermoforming machines in Europe. In addition to consistent quality, this also guarantees the lowest possible manufacturing costs and thereby a cheap m³ price for the entire infiltration or attenuation system. The tunnel geometry is of rigid construction made of recyclable HDPE plastic.

DRAINMAX tunnels are fast and easy to install, because of their light weight, with a storage capacity of 1.6 m³ (420 gallons) per chamber. They can be installed in minimum space, such as below parking lots, bioretention areas, or any small area. In the smallest of spaces, DRAINMAX tunnels allow seeping or draining away of surprisingly large stormwater flows. Plus, excavation depth is lower than with many other solutions.

drainmax stormwater management


  • Constant level of efficient infiltration thanks to its easy cleaning and maintenance
  • Minimum space requirement due to 100% attenuation volume compared to 35% for gravel
  • Latest manufacturing techniques
  • 13.2 ton and 66-ton load capacity options
  • 1.6 m³ (420 gallons) large volume per center tunnel segment
  • DIBt® approval
  • Fast and user-friendly installation and maintenance
  • RECYCLED HDPE construction for strength and affordability
  • Long life and durability: manufactured to 50-year durability standards

To ensure maximum stability, DRAINMAX tunnels undergo rigorous quality control and load testing.

In addition to manufacturing tests, quality tests are on-going in long term 3rd party testing which monitor short and long-term resistance of the tunnels.



Infiltration Trench

drainmax trench
Benefits Include
  • 13.2 ton and 66-ton load capacity options
  • Washable floor and walls
  • Easy to assemble
Product Article Numbers
  • Middle Tunnel 422 gallons (1600 liters) for class SLW 60: 500150
  • Middle Tunnel 422 gallons (1600 liters) for class SLW 12: 500160
  • DRAINMAX Tunnel start cap with 26 gallons for class SLW 60: 500152
  • DRAINMAX Tunnel end cap with 26 gallons for class SLW 60: 500151
  • DRAINMAX Tunnel start cap with 26 gallons for class SLW 12: 500162
  • DRAINMAX Tunnel end cap with 26 gallons for class SLW 12: 500161

DRAINMAX Accessories

Geotextile Membrane

drainmax geotextile membrane
  • The Geotextile 300 GSM is especially suitable for covering the DRAINMAX tunnels: Article Number 500026
  • The Geotextile 190 GSM is especially suitable as a basis underneath the DRAINMAX tunnels: Article Number 500034

DRAINMAX Accessories

Discharge Throttle

discharge throttle rainmax

If stormwater is not permitted to flow into the public drainage system at full flow rate, the continuous INTEWA discharge throttle ensures the maximum permissible flow is released irrespective of the water level.

    Product Article Numbers: Suitable up to
  • 8 gallons per minute: 800030
  • 26 gallons per minute: 800040
  • 61 gallons per minute: 800050
  • 160 gallons per minute: 800022
  • 320 gallons per minute : 800023
  • 475 gallons per minute: 800024
  • 2860 gallons per minute: 800026
  • 3970 gallons per minute: 800025
  • 7300 gallons per minute: 800027