Access Waback

WaBack Access

Basement flooding

The WaBack Access Chamber provides you with peace of mind. Once installed the WaAccess chamber provides complete protection against backflow in the sewer or combined sewer network. 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 WaBack module 

• Delivered complete - inspection chamber and check valve in one

Access Waback

We designed the WaBack to provide instant, automatic protection against backflow. Our engineers designed WaBack Access to work on differential pressure to ensure that in times of need the valve simply protects. No electricity or human interaction required, and without constant maintenance WaBack Access Chamber protects against flooding caused by surcharged sewers.

With long life-cycle cost as part of our DNA we’ve ensured that WaBack Access is designed and constructed using materials designed to withstand the rigors of sewer applications. Each part of the WaBack Access is designed to tolerate chemicals usually found in sewer applications with ease. The only maintenance required for the Access Chamber is that the WaBack module is removed for inspection and rinsing 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 WaBack module is removed.

WaBack Access valve in normal operating position. It works as an ordinary chamber. The waste water flows freely through the valve without restriction thereby eliminating blockages.

When backflow occurs water enters the manhole from the outlet.  The flotation pipe is kept above water level.  Rising water is prevented from flowing back into the pipe system.

The water level has risen and the valve is completely filled. The mouth of the pipe is pressed against the sealing disk. The water level can rise above the pipe without any risk of backflow into the system. The pipe returns to its original position when the water level in the valve drops.

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 WaBack Access chamber to ensure our products fit real life applications. The following dimensions are available:


Article number Nominal size DN [inch] Riser [inch] Shop Drawing (PDF) Shop Drawing (DWG) Technical Specification
WA110-425-1 4" PDF PDF pdf

WaBack Access Chamber is a complete inspection chamber Ø18" with NPS 4" connections. Inside the chamber is a WaBack check valve to prevent backflow. The ‘easy-remove’ backwater valve can be removed from ground level allowing easy rinsing and allows simple inspection. The WaBack module can be installed on sewage, drainage and surface water networks. Our WaBack is designed to be used in heavily polluted water and can therefore be used in both sewer and stormwater applications. When designing WaBack Access we chose to have a completely open flow area to ensure blockages won’t occur. Experience has led to further development of the WaBack Access. Our engineers have fine-tuned the mechanism to ensure decades of low maintenance protection and there is an optional alarm to inform the home owners that WaBack Access is protecting them from flooding.



Advantages of WaBack Access

  • Easy access from ground level
  • Ease of inspection – lift manhole cover and pull up the WaStop module
  • Delivered complete – inspection chamber and check valve in one
  • The WaBack module is completely open for flow during normal operating conditions
  • Allows ventilation in the pipe network
  • The valve closes as soon as backflow occurs Confidence – WaBack valves have been used for over 20 years!

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 roll. If you require any further information please call us straight away. 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

The WaBack non-return valve and WaBack Access has been thoroughly tested by both laboratories and councils in Sweden, Norway and Denmark. All tests show that all WaBack models are effective in stopping flooding caused by backflow and that it requires minimal maintenance. WaBack and WaBack Access are certified for use in storm water and sewage systems. The entire WaBack range is CE approved according to regulations for building products. WaBack check valves are for use as a non-return valve of Type 1 for back flow in sewage and drainage systems. SS-EN-13564-1:2002.


Wapro Access Chamber prevents backflow. Wapro Access Chamber is delivered with WaStop® already installed, and 5' spindle extension. The chamber is constructed to fit shaft dimension xxxmm. 

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


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

A rigorous testing procedure is undertaken at Wapro to ensure our valves meet our exacting standards. Our valves tested to appropriate standards in our target markets at third party organization Kiwa Sverige AB on an annual basis.

CE-approved models type 1 (NPS 3-8") are tested according to SS-EN 13564-2:2002.
WaBack Access also meets the requirements according SS-EN 13564-1:2002 and quality assurance according SS-EN 13564-3:2004.

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