The Drainwell module system is very versitile and can be utilised for leech drains (from a septic tank), soakwells (for stormwater management) or as an underground tank.
Features and Benefits
- Strong structural design - can be installed under driveways, carparks and other trafficable areas therefore increasing the use of valuable land.
- Infiltration - large permeable area including sides and ends.
- Detention - Alleviates onsite/downstream flooding.
- Retention - Can be used as a retention tank so that it is easy to collect, store and reuse precious rainwater.
- Larger volumes with fewer modules - projects require fewer modules resulting in less assembly time.
- Chemically inert - the units will not be affected by harmful chemicals, therefore increasing the product life.
- 90mm and 150mm Cut Out Guides for DWV - Allows for simple pipe connection therefore less time is taken for installation.
- UV Stabalised - for increased product life.
- 100% Recycled Polypropolene - Environmentally freindly.
- Modular - The units interlock vertically and position horizontally to create any size and shape required.
- Lightweight - easy to handle. No crane required.
- Flat Pack Form - Easy to transport and save on bulky transport expenses.
- Manufactured in Australia.
Measurements
Each Drainwell Module is made up of a number of large and small plates. Each large plate measures 755mm long x 400mm wide x 20mm high. Each small plate measures 400mm long x 440mm high x 20mm wide. One complete Drainwell module measures 755mm long x 400mm wide x 440mm high.
Capacity
Each module will hold a capacity of 132 litres.
Tanks per m3
7.5 tanks fit into one cubic metre of space.
Types
There are three main types of Drainwell:
- Normal Duty - maximum load of 23.66 t/m2
These modules feature three small panels (with one internal panel)
- Heavy Duty - maximum load of 29.76 t/m2
These modules feature four small panels (with four internal panel)
- Extra Heavy Duty - maximum load of 32.42 t/m2
These modules feature five small panels (with three internal panel)
Height of Units
The Drainwell units can come in the following heights:
- 1 Layer (440mm high)
- 2 Layers (860mm high)
- 3 Layers (1280mm high)
- 4 Layers (1700mm high)
- 5 Layers (2120mm high)
When stacking the units in layers, for each layer that is added to the stack, a saving of one large plate is made per module. For example, 4 individual units utilse 16 large plates, where a unit that made up of four layers only utilises 13 large plates.
COMPONETS OF A MODULE

LARGE PANEL (WITHOUT PINS)
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SMALL PANEL (WITH PINS)
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MODULE ASSEMBLY INSTRUCTIONS
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STEP 1 Place 1 x Large Panel onto a firm flat surface. Then insert the required number of Small Panels with the 400mm side into the Large Panel.
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STEP 2 Insert 1 x Large Panel onto the top of the Small Panels.
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STEP 3 Turn module over and insert 1 x Large Panel onto the top.
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STEP 4 Turn module over and insert another Large Panel onto the top.
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MODULE STACKING

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Follow Steps 1 to 3 above and place the incomplete module on top of the completed module and use a rubber mallet to tap the modules firmly together. |
TYPICAL INSTALLATION INSTRUCTIONS
INFILTRATION SYSTEM
- Form a pit by excavation, according to specified dimensions.
- Level base of pit and compact.
- Backfill pit with a minimum 100mm of coarse sand, and compact.
- Line base and walls of pit with Geotextile ensuring that seams have a minimum 200mm overlap. Seal joints with adhesive PVC tape. Allow sufficient Geotextile length to cover the surface of the Drainwell modules once positioned in pit.
- Place assembled Drainwell modules into position, on top of Geotextile, inside pit. Ensure modules are placed with 440mm side in the upright position.
- If required, secure Drainwell modules together with clips or heavy duty cable ties.
- Cut holes in the correct position for inlet and outlet pipes. Outlet must be positioned lower than inlet.
- Tightly cover the sides and top of modules with Geotextile. Ensure overlaps and inlet/outlet areas are sealed with adhesive PVC tape.
- Backfill around sides and top of modules with minimum 100mm clean coarse sand and compact according to engineers specifications.
- Backfill a minimum 600mm of clean fill on top of modules and compact according to engineers specifications.
DETENTION/RETENTION SYSTEM
- Form a pit by excavation, according to specified dimensions.
- Level base of pit and compact.
- Backfill pit with a minimum 100mm of coarse sand, and compact.
- Line base and walls of pit with Geotextile ensuring that seams have a minimum 200mm overlap. Seal joints with adhesive PVC tape. Allow sufficient Geotextile length to cover the surface of the Drainwell modules once positioned in pit.
- Line base and walls of pit with UV stabilised Polypropylene Liner (min. 400 micron). Seal joints with tape supplied. Allow sufficient liner length to cover the surface of the Drainwell modules once positioned in pit.
- Install a second layer of Geotextile over the PPL.
- Place assembled Drainwell modules into position, on top of Geotextile, inside pit. Ensure modules are placed with 440mm side in the upright position.
- If required, secure Drainwell modules together with clips or heavy duty cable ties.
- Cut holes in the correct position for inlet and outlet pipes. Outlet must be positioned lower than inlet.
- Tightly cover the sides and top of modules with Geotextile. Ensure overlaps and inlet/outlet areas are sealed with adhesive PVC tape.
- Backfill around sides and top of modules with minimum 100mm clean coarse sand and compact according to engineers specifications.
- Backfill a minimum 600mm of clean fill on top of modules and compact according to engineers specifications.
ADDITIONAL INSTALLATION NOTES
- It is important that every Drainwell installation is fitted with an overflow or vent.
- Any connection of inlet or outlet piping through liner should be made with a good seal around penetration point.
- Pre-filtration of stormwater is an essential component of every Drainwell system.
- If the Drainwell installation is to be under a carpark or trafficable area, it is recommended to use a layer of woven Geotextile on top of the Drainwell modules. It should extend a minimum 500mm beyond the perimeter of the excavation.