Backflow Valves

KARZB100 Backflow Prevention Valve to fit 110 mm (DN100) pipe (pipe outside diameter 114.3 mm)

KARZB160 Backflow Prevention Valve to fit 150 mm (DN150) pipe (pipe outside diameter 168.3 mm)

KARZB200 Backflow Prevention Valve to fit 200 mm (DN200) pipe (pipe outside diameter 219.1 mm)
Backflow anti-flooding device

Backflow Valves prevent backflow automatically and meet EN13564-1:2001. The valve opens to the full diameter of the pipe to reduce the possibility of blockage, and the lid can be removed for maintenance if necessary. A closure lever allows the valve to be locked shut if required.

The Backflow Valve prevents foul water entering properties and protects lower located rooms against flooding caused by return flow of sewage waters. Such risk occurs most often in sanitary drainage systems and in rainwater drainage systems usually caused by intense rainfall or flooding.

This valve is suitable for rainwater overflows, foul and storm water drainage. It is an effective anti-flooding device when installed on properties susceptible to flooding from rivers. Fit at the debris outlet/overflow of underground tanks to prevent groundwater entering the tank.

The Backflow Valve is the solution to prevent rats and other rodents entering the sanitary and rainwater  drainage systems.

Material : Polypropylene, with stainless steel valve plate and rubber seals

 Maximum Pressure : 0.5 bar

KARZB100 Backflow Valve £98.00 each  (£117.60 each including.V.A.T.)  To purchase click here

KARZB160 Backflow Valve £139.00 each  (£166.80 each including.V.A.T.)  To purchase click here

KARZB200 Backflow Valve £189.00 each  (£226.80 each including.V.A.T.)  To purchase click here

Availability: 2-3 days

FREE UK mainland delivery (excluding Highlands & Islands)

Backflow anti-flooding device

Back water valves are covered by a 24-month guarantee.



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 Dimensions: KARZB110 (mm)

 Dimensions: KARZB160 (mm)


Backflow Valves are manufactured from high-quality polypropylene (PP), a very durable material that is mechanically resistant as well as resistant to aggressive effects chemicals and to hot wastewaters.
Cover mounting bolts are chromium-nickel stainless steel of OH18N9 type.
Cover and flap gaskets made of EPDM rubber with improved resistance to weather factors and ageing.
Smooth, suitably-profiled interior surfaces prevent gathering of sediments.
Backflow (non-return) valves are installed in horizontal drain pipes before a drainage-system outlet from a building, or in the house drain pipe, prior to its connecting to external sewer, most often they are mounted in inspection chambers.
Main Features
  • Simple to install
  • Operates fully automatically, no external power-supply needed. 
  • Substitutes an inspection chamber, mounted at sewage system outlet from the building. 
  • Resistant to effects chemicals and to hot wastewaters
  • Permits temporary blocking of wastewater flow (for overhaul works)
  • Maintains full flow capacity of the sewage system
  • Easy to operate and to maintain.


Back Water Valve installed in man hole

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 Pictures are for illustration only.