Backflow Protection: FAQs

When can a filling loop be used?

Where a closed circuit (heating system etc) has been categorised by the water undertaker as a fluid category 3 risk, the installation of a compliant double check valve on the fill point connection to the supply/distribution pipe may be considered as acceptable backflow protection.

Where a fill point connection incorporates a “flexible connection”, when not in use it is good practice for the hose to be completely disconnected and removed. However, a partial disconnection, that is to say only detaching one end of the hose, may be acceptable providing the disconnection is made between the hose and the backflow prevention device on the supply/distribution pipe.

Please note: if the water undertaker has concerns about the likelihood of contamination, or the suitability of a double check valve - for example due either to age, operating temperature or pressure fluctuations – under schedule 2 paragraph 15(4) they can require the installation of additional backflow protection.

For further information contact the local water undertaker.





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Uncontrolled if downloaded. This is informative, non-statutory guidance and intended for general guidance purposes only; it is subject to change.

Compliance with this information should not be relied upon as guaranteeing no enforcement action will be taken by water undertakers. Water Regs UK accepts no liability for loss, indirect or consequential loss arising from or in connection with this guidance document.

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