Green Drain GD35/4 waterless trap seal with extended gasket for 3.5 to 4 inch drains

Main

Side

Top

Inside

Parts

Available Internationally GD35/4

3.5-4" Waterless Trap Seal

Name: GD35/4 Waterless Trap Seal
Brand: Green Drain
SKU: GD35-4-EG

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

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

Flow Rate 323.17 L/min

Install Time 30 Seconds

Request a Quote Contact Us

WaterMark Certified

ASSE 1072 Tested

International Orders Available

Cutaway view of a 3.5 to 4-inch floor drain and its trap

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, odors, 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 tested. The data that matters.

The GD35/4 is tested to ASSE 1072-2020, the North American performance standard for barrier-type floor drain trap seal devices. WaterMark certified (Australia).

323.17 L/min Flow Rate (Level U) High-volume capacity for commercial drainage.

32g Opening Force Approx 1.1 oz (32 g). Opens under minimal water weight.

2,500+ Cycle Endurance ASSE 1072 tested open/close cycles.

>96% Evaporation Reduction Keeps trap seal intact without water priming.

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 BSD SpecLink and 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 (DN110)
Patents	Multiple US & international patents