GD-SSD Waterless Trap Valve
The GD-SSD gives you back the space a P-trap takes. It is a straight one-way drain valve under 4 inches long that sits in the line under sinks and appliances, in buildings, RVs and boats. It seals with silicone, not water, so there is no U-bend to work around and nothing to evaporate, freeze or slosh out.
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Distributors, wholesalers and OEMs: tell us about your business and we will reach out ahead of release.
Dimensions are from the factory drawing. Sizes, pipe connections, listings and pricing will be published at release.
Take back the space under the sink.
A P-trap hangs a U-bend of standing water below the drain, and everything in the cupboard has to fit around it. The GD-SSD is a straight valve that sits in the line itself. No U-bend, no water, and the space below it is yours again.
- GD-SSD
- 3.69 in (93.8 mm) long, end to end. Straight, no water.
- A typical 1-1/2 in P-trap
- 4-1/4 to 6-1/4 in from the inlet to the bottom of the bend, before the arm to the wall, and full of water.
- Room for storage under a vanity or a galley sink
- Fits upright or on its side, wherever the drain runs
- No standing water to spill when the line is opened
Whether the P-trap can come out is up to your plumbing code. See where the codes allow it.
GD-SSD length from the factory drawing. P-trap heights from manufacturer specification sheets for 1-1/4 and 1-1/2 in tubular traps.
How the GD-SSD works.
A P-trap keeps sewer gas out of a room with a few inches of standing water. Where that water can stay put, it works. The GD-SSD is for the drain lines where it cannot.
Water arrives
The fixture drains into the GD-SSD inlet. The pressure of the water pushes the silicone skirt open and the water flows straight through the body and on down the line.
Flow stops
The moment the flow stops, the skirt relaxes closed. Nothing is stored inside the GD-SSD. There is no pool of water to keep topped up.
The line stays sealed
Air, odor and pests from the drain side meet a closed silicone valve. It stays closed whether the fixture was used an hour ago or a season ago.
The GD-SSD uses the same silicone skirt valve that seals the Green Drain floor-drain trap seals, built into a short inline body with a connection at each end.
Where the code lets it replace the P-trap.
Whether the GD-SSD can take the trap's place, and all the space the trap used, is decided by the plumbing code where it is installed. Where the code calls for a water-seal trap, the GD-SSD goes in the line above it.
- Australia: AS/NZS 3500.2
- The sanitary plumbing and drainage standard requires every fixture to have a trap or a self-sealing device. A self-sealing valve is a recognised alternative to the P-trap.
- US RVs: NFPA 1192
- The standard for recreational vehicles allows a waterless trap in an RV's drain lines, in place of a water-seal trap.
- US condensate drains: UPC and UMC
- The 2024 Uniform Plumbing and Mechanical Codes name a sanitary waste valve as one way to protect condensate lines that join a shared waste.
- US homes and buildings: IPC and UPC
- The codes call for a water-seal trap on each fixture. The GD-SSD fits in the line above it and keeps the drain sealed on the day that trap's water is gone.
Codes are adopted and enforced locally, so check with your local authority before you plan an installation. The GD-SSD's certifications and listings will be announced at release.
Built for the road first.
A P-trap in an RV has a hard life. The water sloshes out on the highway, evaporates while the rig sits, and freezes in storage. Every time it is gone, the holding tank breathes into the cabin.
The GD-SSD holds no water, so none of that happens. It fits in the line under the galley sink and the lav, flat in the run where the trap used to hang, so the cupboard below is yours again. And it stays sealed whether the rig was used yesterday or last season.
- Nothing to slosh, evaporate or freeze
- Under 4 inches long, for the space an RV gives you
- Fits above the trap you have, or in place of it where the code allows
- The same logic for boats, trailers, tiny homes and cabins
Where the GD-SSD goes.
The GD-SSD sits in the line, upright or on its side, wherever a drain runs. These are the places we drew it first.
Under a basin
On the tailpiece, straight down from the drain, one run to the wall.
In the horizontal run
After the elbow, in the run to the wall, where the trap's outlet would be.
Laundry standpipe
At the top of the standpipe, with the P-trap left in place below it.
Laundry outlet box
Straight out of the box, at the top of the standpipe, before the run drops away.
Backflow preventer drain
On the drip-pan drain under a backflow cabinet, a line that only sees water when the relief port opens.
Condensate line
Inline on the small-bore drain from a wall unit.
RV galley
Between the sink and the holding tank, where a trap sloshes out on the road.
And the rest of the list, in the fixtures and places a water seal gives the most trouble:
- Kitchen sinks
- Bathroom sinks
- Dishwasher drains
- Washing machine standpipes
- Utility sinks
- HVAC and boiler condensate
- Backflow preventer drains
- RVs and travel trailers
- Boats
- Tiny homes and cabins
- Second homes and seasonal buildings
Replace the GD-SSD cartridge, not the valve.
The working part of the GD-SSD is a cartridge that sits in the inlet end of the body. It carries the silicone skirt valve. Everything else, the body, the seals and the compression nuts, is plumbing that stays in the line.
When the cartridge needs replacing, it comes out of the inlet end and a new one goes in. Replacement cartridges will be sold on their own. You do not cut pipe, you do not buy a new valve, and you do not disturb the fittings.
Ten ways a water seal goes missing.
A bathroom at home, a restaurant kitchen, a laundry room, a rig on the road: every P-trap in every one of them depends on a few inches of water staying exactly where they are. A dry trap is an open pipe to the drain. These are the ways the water leaves, and where each one happens. Every one of them is a place the GD-SSD earns its keep.
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01
Evaporation A trap that is not used dries out between visits, and the smell arrives before anyone does.Second homes, guest baths, seasonal buildings
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02
Freezing Standing water in an unheated space freezes, and a frozen trap can crack.Cabins, stored RVs, unheated buildings
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03
Wicking and leaks Hair over the weir wicks the water out an inch at a time; a loose slip nut drips it out.Any bathroom sink, any old trap
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04
Self-siphonage A full basin emptying fast drags the trap's own seal out behind it. That gurgle at the end is the seal leaving.Kitchens and bathrooms, any building
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05
Induced siphonage A washer pumping out or a tub draining on the same branch pulls the seal out of a trap that was not even used.Laundry rooms, apartments, shared branches
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06
Back pressure Water from fixtures above compresses the air in the stack and blows the seal up into the fixture at the bottom.Tall buildings, the bottom of a stack
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07
Momentum A bucket emptied in one pour carries the water through the trap faster than the trap can refill.Mop sinks, restaurants, janitor closets
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08
Foaming Detergent foam backs up the branch and takes part of the seal with it when it collapses.Laundry rooms, dishwashers, commercial kitchens
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09
Wind Wind over the vent stack pushes and pulls on the air in the pipe; every gust rocks a little of the seal out.Buildings with a roof vent, exposed sites
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10
Movement Water sloshes out of a trap on the road and on the water, on the first rough mile.RVs, trailers, boats
Plumbing codes decide where a trap may be replaced and where it may not. Installation instructions and the applicable listings will be published with the product.
For distributors, RV makers and HVAC contractors.
The GD-SSD will reach most of the people who fit it through partners. If you stock plumbing, RV or HVAC parts, build RVs, trailers or boats, or install condensate drains, tell us about your business and we will reach out ahead of release.
Plumbing wholesalers and distributors
A compact part that takes little shelf space, with a replacement cartridge that brings customers back.
RV, trailer and boat makers and dealers
A trap that does not slosh, evaporate or freeze, in the space a galley or a lav can spare.
HVAC and mechanical contractors
A waterless valve for condensate lines, where a water trap dries out between seasons.
GD-SSD questions we are already being asked.
How much space does the GD-SSD save?
The GD-SSD is 3.69 in (93.8 mm) long end to end, a straight valve with no U-bend and no standing water. A typical 1-1/2 in tubular P-trap stands 4-1/4 to 6-1/4 in from its inlet to the bottom of the bend, before the arm to the wall. How much room you gain in your installation depends on the connections, which will be published at release.
Does the GD-SSD replace the P-trap?
The GD-SSD can do either job, depending on the plumbing code where you are. In Australia, AS/NZS 3500.2 allows a self-sealing device in place of a trap, and in US RVs, NFPA 1192 allows a waterless trap; there it takes the trap's job and the space the trap used. In US homes and commercial buildings, the codes call for a water-seal trap, and the GD-SSD fits in the line above it, sealing the drain on the day the trap's water is gone. The GD-SSD's certifications and listings will be announced at release.
Can I use the GD-SSD in my RV or boat?
The GD-SSD is built for exactly that. Under the galley sink or the lav, in the line to the holding tank. It holds no water, so there is nothing to slosh out on the road, evaporate in storage or freeze in winter.
Can I replace just the GD-SSD cartridge?
Yes. The cartridge with the silicone skirt valve comes out of the inlet end and a new one goes in. Replacement cartridges will be sold on their own. The body and the fittings stay in the line.
When will the GD-SSD be available?
A release date has not been announced. Leave your email above and we will tell you when it is available, and nothing else.
What pipe does the GD-SSD fit?
Sizes and pipe connections will be published at release, together with the installation instructions and the fitting kits.
Is the GD-SSD certified or listed?
Listings and certifications for the GD-SSD will be announced at release. The certifications on this site today apply to the Green Drain floor-drain trap seals.
How is the GD-SSD different from the Green Drain floor-drain seals?
The floor-drain seals drop into a floor drain above the existing P-trap. The GD-SSD fits in a drain line, in the run of pipe under a sink or appliance, and seals with the same silicone skirt valve.
I sell plumbing products. How do I get the GD-SSD first?
Use the distributor application and mention the GD-SSD. We will contact you before the public release.
Be first to fit the GD-SSD.
Leave your email and we will tell you the day it is available. Need a floor drain sealed today? The Green Drain floor-drain seals ship now.