What is blue water?

Water companies had been receiving customer complaints of blue water coming through their taps.

  • Water inspectors were sent to investigate, discovering cleaning tablets in the cistern
  • These tablets turned the cistern water blue
  • Depending on the conditions, this blue water can backflow into the main supply pipe
  • Water companies are required to deal with these issues
  • As a result, they issued this new guidance in 2019 to prevent these problems from reoccurring
  • How to identify and eliminate blue water from re-entering your toilet cistern
  • Installing your AirGap™ Delayed Fill Valve
  • How to adjust the water level in your cistern


Overcomes the challenge of blue water

The guidance issued by water companies in 2019 has had an impact on toilets and related products in the UK.

These changes are necessary for our plumbing systems to adhere to health and safety compliance, driven by something which has become known in the industry as ‘blue water’. This is the term used for the visual indication of backflow, when fluid from a toilet cistern re-enters the main supply pipe, having been coloured by a blue loo block.

Our newest generation AirGap™ fill valve has been designed in the UK and we have worked closely with with water companies and test laboratories to ensure absolute compliance to every standard and regulation.

The valve is fully compatible with the requirements of AUK1, the type AG Air Gap and is BS1212-4 certified. It is the first bottom inlet, height adjustable product to have achieved this and is a milestone in Fluidmaster innovation.