Green Drain GD35/4 waterless trap seal for 3.5 to 4 inch Australian floor drains

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APAC Exclusive GD35/4

3.5-4" Waterless Trap Seal

Name: GD35/4 - Waterless Trap Seal (Australia)
Brand: Green Drain
SKU: GD35-4-EG
Price: 59.70 AUD
Availability: InStock

Extended gasket design bridges 3.5" to 4" drain openings for seamless compatibility across Australian plumbing systems. WaterMark certified.

$59.70 AUD

Inc. GST. Free shipping on orders over $100 AUD. $10 flat rate standard shipping.

Pipe Size 3.5-4" (89-108mm)

Flow Rate 323.17 L/min

Install Time 30 Seconds

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Will it fit? Measure the pipe opening under the cover, inside wall to inside wall.

Watch how to measure Size chart

Measuring keychain $6.95 AUDA cutout for every size, so you order the right one.

Size chart

Measure the pipe opening inside wall to inside wall, then find the row your reading falls in. Go by the millimeters: the inch size is only the pipe’s name.

Model	Pipe opening	Size
GD125	32 to 38 mm	1.25"
GD15	39 to 47 mm	1.5"
GD2	51 to 59 mm	2"
GD25	55 to 65 mm	2.5"
GD3	68 to 81 mm	3"
GD35	89 to 95 mm	3.5"
GD4	99 to 107 mm	4"
GD5	125 to 133 mm	5"
GD6	149 to 157 mm	6"
Hybrid models, for openings between the sizes above
GD3/35	77 to 95 mm	3 to 3.5"
GD35/4 this page	89 to 108 mm	3.5 to 4"

Full measuring guide

WaterMark Certified

ASSE 1072 Tested

Free Shipping Over $100

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 to 4-inch drains, 89 to 108 mm, and drops in by hand. No tools, no plumber, installed in seconds.

Will it fit? Measure first

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 GD35/4 seats in a pipe of 89 to 108 mm. If the opening is oval, use the smaller reading. Outside that range, another size fits: see all sizes.

Drain in section with the grate highlighted: not the part to measure

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.

Drain in section with the bowl highlighted: not the part to measure

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.

Drain in section with the pipe highlighted: the part to measure

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.

Floor drain from above with the grate off: a tape across the pipe opening from A to B — **Measure A to B.** The pipe opening at the bottom of the bowl.

Full installation guide: how to measure, choose a size and install.

Common drains it fits

GD35/4 installed in a round floor drain — Round

GD35/4 installed in a square floor drain — Square

Not seeing your drain? If its outlet is a round pipe in the GD35/4's range, it fits. The cover on top does not matter; the pipe under it does. Remove any basket or strainer first.

GD35/4 in section with water flowing down through the open skirt — **Water flowing.** The silicone skirt opens and water passes.

GD35/4 in section with the skirt closed and sewer gas held below — **Flow stopped.** The skirt closes. Air, odor and insects stay below.

The valve, two states

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.

Step 1: the grate lifted off a floor drain, shown in section

Lift the grate

Most grates lift straight out by hand. Some are held by one center screw; back it out, then lift.

Step 2: measuring the pipe opening at the bottom of the drain, inside wall to inside wall

Measure the opening

Measure the pipe opening at the bottom of the bowl, inside wall to inside wall. The GD35/4 fits 89 to 108 mm.

Step 3: the GD35/4 being pressed down into the pipe opening

Press gently to seat

Recess 2 to 4 inches below the pipe top. The extended silicone gasket creates a snug seal against the pipe walls.

Step 4: the grate back in place over the seated GD35/4

Replace the grate

Put the grate back. Done. A full commercial floor in an afternoon.

ASSE 1072-2020 Performance Data

Independently tested by IAPMO R&T. These are lab-verified results from an accredited third-party testing laboratory.

323.17 L/min Flow Rate (Level U) No restriction to drainage.

32g Opening Force Opens with approximately 32 grams (1.1 oz) of water.

2,500+ Cycle Endurance Open/close cycles tested and passed.

>96% Evaporation Reduction Maintains trap seal without water.

For Architects & Engineers

Specify Green Drain in your next project.

Download the Revit family set for every Green Drain model and find us listed in MasterSpec.

Download Revit Families View full specifications →

Technical Specifications

Model	GD35/4
Pipe Size	3.5-4" (89-108 mm)
Height	50 mm
Housing Material	ABS Plastic
Valve Material	Silicone Rubber
Seal Material	Silicone Gasket (Extended)
Flow Rate	323.17 L/min
ASSE 1072 Opening Force	32 grams
ASSE 1072 Cycle Life	>2,500 cycles
ASSE 1072 Evaporation Reduction	>96%
WaterMark License	WM-022837 (DN100)
Patents	Multiple US & international patents

Industries we serve.

The extended gasket ensures a secure fit across 89-108 mm pipe diameters.

Healthcare Commercial Kitchens Schools Hotels Commercial Office Restaurants Industrial Food Processing

Certifications and compliance.

WaterMark Australia

WM-022837 (DN100)

ASSE 1072-2020 Standard

Barrier-type trap seal performance standardEvaluated under IAPMO R&T cUPC File No. 9301

CE / ETA-18/0536

European Technical Assessment

NSF/ANSI 2

Food Equipment Certified

HACCP International Certification

Food safety certification (Certificate RG-05)

DTI Test Report

Rapport 957187

SGS

SGS Aerosol-Retention Test

Retained over 99.9% of an aerosolized MS2 bacteriophage viral surrogate

View All Certifications

What operators are saying.

"4 months have gone by and I have yet to have a single complaint or concern since the Green Drains were installed."

Winston Andrews, CEO

Pleasanton Unified School District

"Once installed the Green Drain solved our issues. No more need to flush the drains or add enzymes. This product really works!"

Jeff Bowe, Project Manager

Raven Services Corporation (14-story federal complex)

"We have used the following product in all of our bathroom drains, and this has not only eliminated our odor problem, but it has made our internal customers safer."

Mike Malone

FedEx Corporation

For architects and engineers.

The GD35/4 is designed for Australian plumbing systems compliant with AS/NZS 3500. For WaterMark certification details, ASSE 1072-2020 performance data, and the complete certification matrix, see the Architects and Engineers technical page.

WaterMark License WM-022837

Pipe Compatibility 89-108 mm (3.5-4")

Patents Multiple US & international patents

View A&E Resources

Technical Drawing
or Spec Sheet Preview
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Ready to protect your drains?

Drop-in install. No tools. Works from day one.