Water Tank Regulations

Potable & Non Potable Water

Water safety regulations for potable water

A lot of older buildings have cold water storage tanks located in the attic or loft space. In the majority of buildings, the water storage tank will provide cold water to upstairs toilets and in some properties, all cold-water taps are fed from this tank.

The condition of the water storage tanks has an effect on the quality of water being stored. Poor quality water tanks have an effect on the quality of water, which should not be used for potable drinking, food preparation or cleaning teeth.

Taps connected to a main water supply are the only certified potable source of drinking water unless the attic tank is installed to the correct regulations for drinking water, and kept in good condition.


Is my water storage tank in good condition?


If you have a water storage tank for drinking water, it should meet the following requirements:


  1. Water storage tanks with a capacity of 250 litres is adequate for most domestic homes. Do not buy water tanks that are too large as it is important that the water is frequently replenished with fresh water.


  1. Check that your water tank is manufactured from approved materials. Glass reinforced plastics (GRP) or Polyethylene are approved for water storage, make sure the type of water tank purchased is for potable drinking water as the design will be different to non-potable water storage tanks. Older tanks have been made from galvanised iron, which rust over time, which can discolour the water and leave a bad taste. Look for WRAS approved product logos which ensure the product is approved for drinking water.


  1. Water tanks manufactured for drinking water will have a fitted lid come as standard, these are imperative for keeping out light, dust, vermin etc. which cannot get into the tank when secured.


  1. Drinking water tanks will have vents and overflows designed into them that work as a screen so insects and particles cannot contaminate the water.


  1. All water tanks are required to be insulated and not exposed to sunlight, to keep the water as cold as possible.


  1. Always carry out periodic checks to ensure the tank is in working order, the lid is intact and a build-up of scale or deposits have not formed.


  1. In public buildings, workplaces, and social housing all water tanks will be checked and cleaned as part of the arrangements that must be in place for legionella control purposes. If you are living in a rental property our landlord is responsible for these checks.



Quality of Water in an attic tank will deteriorate if:

  • There is no lid secured
  • The water becomes warm
  • Stagnant water, no turnover of water
  • Tank is manufactured from non-approved materials
  • Servicing/work carried out by an unqualified person.



What if I suspect the water is unsafe?


If the water is not fit for human consumption or has been contaminated in any way contact your local water company, or the local environmental health department. If you are responsible for the tank, guidelines and advice will be provided to you on how you can make improvements to rectify the water supply to normal drinking water. Speak with our technical sales team today for advice and a quote on tank replacements.


Replacement water storage tanks?

 You will need to make sure a replacement tank is of an approved type and installed correctly by an approved plumber. Certain changes to internal plumbing systems require prior notification to the local water company.

If your attic/loft tank needs replacing contact our sales team who will give you free advice and a custom quote for a new WRAS approved water storage tank for the potable water.

Nicholson Plastics - GRP Water Storage Tank

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GRP Cold Water Storage Tank

Manufacturer & GRP Supplier Since 1968