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WaStop Inline Check Valve for Pipe ID 492-504mm

We know that any solution for flood prevention or odour control needs to function simply and effectively. That’s why we teamed up with WaPro to offer the WaStop® inline check valve. Invented in 2000 it was designed with one thought in mind. Instant, automatic protection. Working on differential pressure the WaStop® functions autonomously. Without any human interaction, electricity or constant maintenance – it just works. Available to fit most types of pipes from DN75 to DN1800. Similarly, available in an access chamber for easy access from ground level. It has the lowest head-loss on the market and 100% backflow prevention. The unique pulsating flow keeps pipes both upstream and downstream cleaner. Therefore, reducing maintenance costs. This page contains downloads and technical information including drawings, head-loss details and opening pressures for the Stainless Steel WaStop® suited to Pipe ID 492mm-504mm.



ACE WaStop Brochure
Technical Specification PDF: WaStop 500mm
Drawing PDF: WaStop 500mm
DWG: WaStop 500mm
WaStop Installation & Operating Manual
Poole WaStop Case Study
Hull WaStop Case Study
Anglian Water WaStop Case Study



  • Quick and Easy to install, at any angle
  • No mechanically moving parts
  • Low head losses
  • Virtually maintenance free
  • Resistant to blockage

The WaStop ® inline check valve is a simple yet highly effective design. Using very few components. Ensuring reliable performance with virtually no input once installed.

Installation can be into, between, or at the end of pipes in a variety of ways. Ideal for retro-fit into existing systems as it can be installed at any angle. In the majority of cases, it is installed by pushing into place, and secured with either with bolts or a flexible coupling. Therefore, very quick protection from flooding.

The unique membrane design of the WaStop ® inline check valve ensures positive closure when no flow is present. Meaning very little head is required to open it. Therefore, the activation point of the valve is relatively low. The flushing action clears debris when it activates. In other words, it’s a device you can depend on.

As the membrane pops open, a sudden rush of water passes through it clearing downstream debris. As the water is discharged the membrane pops closed. Reducing the likelihood of debris getting trapped in the gap.




When compared to flap valves or duckbills the WaStop® requires much less head to open. Therefore, in many cases a smaller valve and smaller diameter pipework can achieve the same result. For example, a WaStop® of 215mm can achieve the same head-loss as a typical duckbill of over 300mm. Reducing the diameter of the pipe, handling issues and excavation costs means the overall cost much lower.




Usually used for prevention of backflow in water pipes. In addition, it is also often used for odour protection. Ideal for ceilings of sewers, drains from cellars and air release in offshore pipelines. Where there is no headwall present it can also be used vertically.

ACE are stockists of the WaStop®. For pipe diameter up to 300mm quick dispatch is available. We also regularly supply custom-built WaStops® for pipes up to and including 1500mm diameter. Please contact us for more details.

For more information on the WaStop® and it’s applications, please see our case studies.

WaStop ® inline check valve is available as:

  • PVC- for connection to standard PVC pipe, using off the shelf push fit couplings.
  • Stainless Steel (304 or 316) housing, with various fitting types:
    • Insertion into pipe, wall fixing or flexible coupling
    • Inline connection, using flexible couplings
    • Flanged connection (1 or 2)


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