3.5" Waterless Trap Seal
Fits 3.5" (DN90) drain outlets. Highest flow rate under 4 inches at 323.17 L/min. Drop-in install, no tools required.
Inc. GST. Free shipping on orders over $100 AUD. $10 flat rate standard shipping.
How it works.
Green Drain is a one-way valve for your floor drain. Water flows down and out. Nothing comes back up.
Inside sits a soft silicone valve. Running water pushes it open; the moment the water stops, it closes and seals tight against sewer gas, odours, and pests. Because it seals with silicone instead of water, it never dries out the way an ordinary trap can, even when the drain goes weeks without use.
It fits 3.5-inch drains, 88 to 95 mm, and drops in by hand. No tools, no plumber, installed in seconds.
Measure the pipe. Not the grate, not the bowl.
Lift the grate. At the bottom of the drain body is a round pipe opening. Measured across its center from inside wall to inside wall, that is the only number that matters. The GD35 seats in a pipe of 88 to 95 mm (3.5 in.). If the opening is oval, use the smaller reading. Outside that range, another size fits: see all sizes.
Don't measure the grate
The grate is the cover you walk on. It sits on top of the drain body and is wider than the pipe underneath, so its width tells you nothing about fit.
Don't measure the bowl
The bowl is the basin under the grate that funnels water down. It is wider than the pipe too. The Green Drain does not sit here.
Measure the pipe
At the bottom of the bowl is the round pipe opening. This is where the Green Drain seats, so this is the width to measure. Wipe it clean, then measure inside wall to inside wall.
Full installation guide: how to measure, choose a size and install.
Any floor drain whose outlet is a round pipe in the GD35's range. The grate shape does not matter; the pipe under it does. Remove any basket or strainer from the bowl first.
One-way. Opens for water going down, closes when the flow stops. No water to top up, no power, nothing to prime.
Inspect the seal around 6 to 12 months in service and replace only as needed.
Installs in 30 seconds. No tools.
Lift the grate
Most grates lift straight out by hand. Some are held by one center screw; back it out, then lift.
Measure the opening
Measure the pipe opening at the bottom of the bowl, inside wall to inside wall. The GD35 fits 88 to 95 mm (3.5 in.).
Press it in
Push the Green Drain into the pipe by hand until it sits 50 to 100 mm (2 to 4 in.) below the top of the pipe. The silicone gasket creates a snug seal against the pipe walls.
Replace the grate
Put the grate back. Done. Nothing to wire, prime or top up, and a full commercial floor takes an afternoon. Lifts out by hand, or with the extraction tool.
Built for high-volume drainage.
Independently tested performance data. The GD35 delivers over 3x the flow capacity of the GD3 at Level U.
Specify Green Drain in your next project.
Download the Revit family set for every Green Drain model and find us listed in MasterSpec.
Technical Specifications
| Model | GD35 |
| Pipe Size | 3.5" (88-95 mm) / DN90 |
| Height | 51 mm |
| Housing Diameter (no gasket) | 78.75 mm (3.100"), bottom 83.6 mm (3.291") |
| Housing with Gasket | 97.46 mm (3.837") wide x 50.82 mm (2.001") |
| Housing Material | ABS Plastic |
| Valve Material | Silicone Rubber |
| Seal Material | Silicone Gasket |
| Flow Rate | 323.17 L/min |
| Pressure Resistance (DTI) | 502 Pa |
| WaterMark License | WM-022837 (DN90) |
| Patents | Multiple US & international patents |
Industries we serve.
The GD35 fits 3.5" (DN90) drain outlets.
Certifications and compliance.
WaterMark Australia
WM-022837
ASSE 1072-2020 Standard
Barrier-type trap seal performance standardEvaluated under IAPMO R&T cUPC File No. 9301
NSF/ANSI 2
Food Equipment Certified
HACCP International
Certificate RG-05
CE / ETA-18/0536
European Technical Assessment
SGS Aerosol-Retention Test
>99.9% MS2 viral-surrogate retention
DTI Tested
Rapport 957187
Ready to protect your drains?
Drop-in install. No tools. Works from day one.