HepvO 1.25 Inch Waterless P-Trap


1.25 Inch Waterless P Trap Introducing the World’s Most Amazing Waterless Drain Waste Valve


“The Hepvo valve is just what we needed for the tricky plumbing in our remodeled bathroom. It has been working great for the past year. Very happy with it.”
C. Meagher

“Awesome product! I’ve told several people about it. I installed one in my kitchen sink and one in my bathroom sink, both of which are in my rv certified tiny house.”
D. Bigelow

“I’ve had a HepvO valve installed in my Airstream for several years and it is great! No risk of freezing and I didn’t have to sacrifice any headroom in the shower. I couldn’t be happier.”

Partnered with HepvO

What is it? / Applications

HepvO® is the innovative hygienic Self Sealing Waste Valve. It replaces the traditional water-seal trap and prevents the escape of foul sewer air from waste discharge systems. Unlike conventional waste traps, HepvO® does not rely on trapped water to create a seal. Water seals are prone to failure by evaporation, siphonage and other mechanisms. Instead, HepVo uses a self sealing membrane which performs the same function as a water seal trap but without the risk of depletion or freezing.

HepvO® actively eliminates negative pressure within the waste system by opening and allowing in fresh air until a state of equilibrium with atmosphere is reached. This means that secondary venting of the waste system via the inclusion of air admittance valves in the waste system is no longer necessary.

Enhance Plumbing Design

The HepvO® valve means enhanced plumbing design and system efficiency, without compromising performance or risking the escape of foul air into the living space from the drain or sewer.

The HepvO® valve can be installed vertically or horizontally (with an adaptor) and is available in 1.5 inch and 1.25 inch. This enables valuable space-saving opportunities to be achieved.


  • Lavatories
  • Bath Tubs
  • Sink
  • Bidet
  • Washing Machine
  • Garbage Disposal (Vertical Only)
  • Urinal (Vertical Only)
  • Boiler Condensate
  • Air Conditioning
  • Condensate
  • Overflow
  • Dishwasher
  • Shower

How it Works

How it works:

HepvO® is a self sealing valve designed to close the waste connection below a sanitary fixture to prevent the escape of foul sewer air into the dwelling.
HepvO® unlike conventional waste traps, does not rely on trapped water to create a seal. Water seals are prone to failure by Evaporation, Siphonage and other mechanisms. Instead, uses a self sealing membrane which performs the same function as a water seal trap but without the risk of depletion or freezing.
The HepvO® Sanitary Waste Valve means enhanced plumbing design and system efficiency, without compromising performance or risking the escape of foul air into the living space from the drain or sewer.


  • Waterless – no need for trap primer
  • Admits Air – auxiliary venting not required
  • One Way Valve – prevents foul odors
  • No Siphonage. No Noise. No Smell
  • Not vulnerable to evaporation or freezing
  • Enables multiple fixtures to be located on the same waste branch
  • Saves cost by eliminating air admittance valves and reducing the amount of pipe used
  • higher flow rates and more rapid discharge from fixtures
  • Can be used safely on all applications, even where discharge is intermittent and a regular tap would dry out
  • Perfect to solve problems in existing failing systems and on applications where fixtures are only used occasionally, such as guest bathrooms, holiday homes, boats and mobile homes

Installation Detail

Click here to view the HepvO® Installation Instructions

Click here to view the HepvO® product tech design guide

Installation Steps:

  1. Cut the tube to length, allowing for the full compression socket depth, (preferably using an appropriate tube cutter).
  2. If using plastic tube remove any loose material from the end. If using metallic tube remove any ‘burr’, and file if necessary to remove any external sharp edges. Mark the socket depth on the tube, and check that the tube section to be joined is free of any surface damage which may affect the joint seal.
  3. Unscrew the cap from the outlet/inlet adaptor and slide the cap and rubber seal onto the tube.
  4. Insert the tube end fully into the socket.
  5. Slide the rubber seal and screwed cap up against the face of the socket, and tighten the cap by hand, (check that the cap is square to the body and does not ‘cross-thread’), hand tight should be adequate to form a proper seal.
  6. Threaded connections can be made to the inlet or outlet of the valve. At the outlet it is first necessary to remove the cap and rubber seal. If making connections to threaded components that do not have an integral seal (for example connection to DWV adaptors) PTFE/TEFLON tape should be applied to the thread prior to assembly.



Click here to view the IAPMO Certificate to US National Standard ASME/ANSI A112.18.8

Click here to view the CSA Certificate for use on RV’s

Click here to view the SAI Certificate of Conformity to Australian Standard ATS5200

Click here to view the Condensate Drain Tech Solution


Is HepvO® used in addition to a conventional trap?
NO, unlike other products which prevent foul odors entering the living space, HepvO® is used instead of a conventional water-seal trap.
Will I still need to install auxiliary venting on waste pipe branches?
NO, HepvO® acts as a highly effective local air admittance device, removing the need for secondary venting.
Can I use acidic drain cleaning chemicals?
YES, the valve is manufactured from a highly inert material and has passed extensive testing with a very wide range of chemicals including both acid and alkaline products.
Do I still need to connect each fixture on its own dedicated waste branch?
NO, HepvO® prevents induced siphonage between adjacent fixture traps so it is now possible to make multiple connections on the same branch. This can save yards of tubing or piping and gives great flexibility for locating fixtures and designing waste systems.
HepvO® is a new product to me - how can I be confident that it will give a good installed performance?
HepvO® is relatively new to the North American market but it is not a new product. It has been in high volume production in the UK since 1997 and it is widely used in Europe, Australia and the Far East. It has attained numerous international approvals against very demanding standards and has achieved an enviable track record of trouble-free performance. There are over 2 million installations worldwide.
Will HepvO® promote better hygiene by stopping the escape of foul sewer air into habitable spaces?
YES – The valve has been proven to perform under conditions in which traditional water seal traps are vulnerable to failure. It will continue to perform under back pressures 10 times greater than those experienced in correctly designed soil and waste systems.
Does the air tight seal break down if a strand of cloth or hair collects in the strainer and falls down between the faces of the valve?
NO – HepvO® has undergone extensive foreign body testing (including IAPMO IGC203-04 and ASME/ANSI A112.18.8). Tests show that the valve will maintain an air tight seal around an obstruction such as hair, fabric, strands or spaghetti.
What is the life expectancy of HepvO®?
Installed correctly can be expected to have a life expectancy at least equivalent to current water sealed traps. In addition is guaranteed against defects in materials or manufacturing for a period of 3 years.
Will HepvO® block easily for example if fat is discharged through it?
NO – Extensive testing has shown that is less prone to blockage than traditional water seal traps. Note: because the ‘straight through’ design of HepvO® it does not trap debris discharged through the waste fixture care should be taken with jewelry and other valuables.
Will the seal be maintained even when the fixture hasn’t been used for some time?
YES – HepvO® does not depend on a water seal and so it will continue to maintain a seal. Even if a fixture never gets used or is used very infrequently.
Does the valve make a noise?
Under normal conditions HepvO® operates silently, unlike normal traps that are prone to ‘gurgle’.
Will it support microbiological growth?
NO – The materials used to manufacture HepvO® will not support microbiological growth for example mold and mildew.