Asbestos and cement cold water tanks

Chartered Surveyor James Bush gives advice on something that may be lurking in your loft.


The purpose of a cold water storage tank is to store water in the house for washing and flushing the WC’s in case the mains is ever cut off. Some older houses, especially those that lack a first floor bathroom won’t have a tank just a direct mains supply.

Commonly such tanks hold around 230 litres (50 gal) and so need to be located high up, often in the roof space. That is a lot of water sitting over the main accommodation and so a full tank must be well supported and ideally this ought to be on a timber deck, such as exterior quality plywood spanning over a number of timber bearers so as to spread the load over several joists and preferably to a supporting wall below.

They also require insulating, ideally with an insulation jacket to prevent any possibility of freezing, expansion and potential leaks from occurring. Insulation should be absent directly below the tank so as to take the chill off the immediate area also helping to prevent freezing.

Modern tanks are made from polypropylene with older tanks being of either galvanised iron, fibreglass or asbestos / cement. Redundant tanks are commonly disconnected, drained down and are often left in lofts due to the actual physical difficulty in removing them. Galvanised steel and fibreglass tanks pose little risk whilst the potential risks posed by asbestos are widely known but, providing the material is maintained in good condition and is not cut, drilled or sanded, removal is not always necessary.

Additionally, there is no convincing evidence that ingestion of asbestos fibres is associated with any risk to health. Nevertheless, for peace of mind, you may wish to remove such tanks.

The Heath and Safety Executive recommend that if asbestos cement water tanks are no longer required then their location should be noted but they should be left in situ. However, if such need to removed, for instance if a loft conversion is planned, then it should be noted that removal is classed as a non-licenced task but that strict controls and procedures must be followed. Further information and guidance can be obtained on the Health and Safety Executive website here 

If you would like advice from a building surveyor on the state of your water tank, Woodward Chartered Surveyors offer a specialist service. Contact our helpful team for a quotation on 01923 920950.

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