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Overflows and Warning Pipes

Clearance and Best Practice 

What Happens if the Warning and Overflow Pipe are Plumbed Incorrectly?

Warning pipes and overflows that are not plumbed correctly can lead to thousands of pounds worth of water damage to buildings. Failure to plumb the warning pipe to a monitored area may lead to faults going undetected for long periods.

The role of the warning pipe is to alert personnel of rising water levels in the water storage tank, indicating a fault or malfunction with the inlet or other connections. This helps to reduce the risk of the water tank overflowing.

If undetected, water levels will continue to rise and exit the tank through the water tank overflow. It is vital that the overflow is correctly piped to a gully or bunded area to accommodate overflow water and avoid flooding, water damage, and possible costly repairs.


Water Tank Overflow

WRAS warning pipe and overflow guidelines

‘Warning pipe’ means an overflow pipe with its inlet located in the cistern at such a height that it will start to flow before the main overflow operates and with its outlet located in a position where the discharge of water can be readily seen.

Source: Regulation 4(1)a Compliance Guide

Preventing Water Tank Overflow

Wherever possible warning pipes should discharge outside a building, however where this is not practicable owing to the design of the building, they may be discharged internally provided the discharge is conspicuous. View the Water regulations guide for examples of acceptable arrangements for the discharge of the warning/overflow pipe.

Source: Regulation 4(1)a Compliance Guide

For more information on water tank overflow, please review our recommended Water Regulations UK guidelines below. We offer water storage solutions for all applications contact our sales team or view our products page for more information.

Recommended Reading & Installation Guidelines

Design Recommendations for Mains Supply Inlets

Storage Cisterns - General Design & Installation Requirements:

Alternative Water Systems Information Leaflet and Guidance

Design & Installation Guidance: Protect Wholesome Water from Light Ingress