WaStop Access

Flood protection
Pests & odors

The WaStop Access Chamber provides you with peace of mind. Once installed the Access chamber provides complete protection against backflow in the sewer or combined sewer network as well as protecting against odour. One ingenious product protects your basement or property from flooding caused by an overload or surcharge in the sewer system. 

• Easy access from ground level 

• Simple to inspect - simply lift manhole cover and pull up the WaStop module 

• Delivered complete - inspection chamber and check valve in one 

Product information

We at Wapro know that any solution for flood prevention, or odour control needs to function. Simply, effectively. That’s why, when we invented the WaStop inline check valve in 2000 we had one thought in mind. Instant automatic protection. Working on differential pressure the WaStop functions autonomously, without human interaction, without electricity, without constant maintenance. It just works. To invent the best inline check valve on the market our engineers went one step further.

WaStop’s ingenious function combines common sense and simplicity, to provide our customers with the best possible protection against flooding, odor control and backflow. In order to protect against flooding, we at Wapro have engineered the WaStop to ensure the lowest possible opening pressure whilst maintaining the best possible seal against backflow. This, combined with the lowest headloss available, gives the most efficient flow conditions, ensuring the fastest evacuation of water. An essential quality of check valves used to protect people and property.

Advantages of WaStop®

  • Installed for almost 20 years worldwide with 100% satisfaction.
  • Easy installation saving on construction & installation costs • Superior construction materials

  • Lowest headloss amongst inline check valves 

  • Low life cycle cost 

  • No moving parts - virtually maintenance-free 

  • Stops liquids, gases, odors, insects and small animals

  • Stops backflow effectively even in low flow events 

Technical specification

We at Wapro love protecting people and property from flooding and in line with our customer promise of common sense and simplicity, we have developed WaStop Access chamber to ensure our products fit real life applications. 

The following technical information relating to WaStop can be found on the tabs below.

  • Drawings
  • Technical Specifications
  • Installation Instructions
  • Certifications
Dimensions & Drawings


Article number Nominal size DN [mm] Riser [mm] Drawing file name (imperial) Drawing file name (metric) Technical specification
WA110-425-3 110 425 PDF DWG PDF DWG PDF
WA125-425-3 125 425 PDF DWG PDF DWG PDF
WA160-425-3 160 425 PDF DWG PDF DWG PDF
WA200-1000 200 1000 PDF DWG PDF DWG PDF
WA315-1000 315 1000 PDF DWG PDF DWG PDF

WaStop Access Chamber prevents backflow. WaStop Access Chamber is delivered with WaStop check valves already installed, and 2,15 m spindle extension. The chamber is constructed to fit shaft dimension 460mm. 

Install the WaStop Access simply by placing it inline and attaching with flexible couplings or muffs. A 2% fall in the pipeline is recommended. WaStop Access Chamber is delivered ready for use.


The only maintenance required is that the WaStop module should be removed for inspection, and rinsed if needed, once a year. After a suspected backflow event it is recommended that the chamber is inspected and rinsed if required. The O-ring in the PVC plate should be greased with silicone or similar every time the WaStop module is removed.

We at Wapro believe in enabling. By being an open organization we learn from, and share with, our customers. Below you’ll find that there is a wealth of information in relation to not only our products, but also other useful and interesting information to help you in your role. If you require any further information please don't hesitate call us. We’re here to help you stop flooding.

Technical Documentation

Technical drawings can be downloaded from the Dimensions and Technical Drawings tab. For your ease, you'll find other related information available for download below.

Certifications and Approvals

Models 100-200mm are tested and approved for up to 5m backpressure. Other dimensions are tested up to 3m meters backpressure. WaStop is patented in the EU, USA and other countries.


Read more about our tests of this product.

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