Potable Water Regulations

GRP Cold Water Storage Tanks

Regulations for potable water safety

For cold water services, storage tanks are to comply with the requirements set out by the Water Supply Regulations & Scottish Water Byelaws, which state the full installation must be designed and installed so that the following guidelines below are followed.

Ref: WRAS Water Regulations Advisory Scheme

Cold Water Storage Tank Components:

All cold-water tank components must conform to requirements of Regulation 4.

In summary, each fitting should be of appropriate quality and suitable for the water tank installation for which it is being used.

All fittings are of an appropriate quality and standard. Each fitting is of appropriate CE marking, conforms to European technical approval or British standard approval or an EEA state specification of an equivalent level of performance.

Each fitting should be installed or altered or replaced or disconnected in a workmanlike manner. To an appropriate British Standard/European technical approval or another national specification of an EEA State which provides an equivalent level of protection and performance; Each fitting specification must be approved by the regulator & Each installation approved by the water undertaker.

Regulations and Byelaws for Water Supply

The Water Supply (Water Fittings) Regulations and Water Supply (Water Fittings) (Scotland) Byelaws, set legal requirements for the design, installation, operation and maintenance of water storage tanks, including all water system, water fittings and water-using appliances.

These requirements prevent misuse, waste, undue consumption and, most importantly to be able to provide safe potable drinking water.

These Regulations and Byelaws apply in all types of premises across all industries.

Water Regulation Byelaws apply from the point the water enters the property’s underground pipe (usually at the stop tap at the property boundary), to where the water is used in water systems, water fittings and water storage tanks.

These regulations do not apply where a property uses a private water supply and does not have a supply of water from a water company. If a top-up supply, from a water company, is in place full regulations/bylaws apply.

Copies of the Water Fittings Regulations, and Byelaws in Scotland, including their schedules are available from Her Majesty’s Stationery Office (HMSO) part of The National Archives, or from Scottish Water using the following links.

England and Wales – Statutory Instrument 1999 No. 1148 which has been amended under subsequent legislation.

S.I.1999 No. 1148 – The Water Supply (Water Fittings) Regulations 1999

Amended under the following legislation:

S.I.1999 No.1506 – The Water Supply (Water Fittings) (Amendment) Regulations 1999

S.I.2005 No. 2035 – The Water Act 2003 (Consequential and Supplementary Provisions) Regulations 2005

S.I.2013 No.1387 – The Construction Products Regulations 2013


The Water Supply (Water Fittings) (Scotland) Byelaws 2014

Northern Ireland – Statutory Rules 2009 No.255

S.R. 2009 No.255 – The Water Supply (Water Fittings) Regulations (Northern Ireland) 2009

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 tanks should not be used for potable drinking, food preparation or cleaning teeth.

Taps connected to the 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.


Cold water storage tanks for drinking water should meet the following requirements:

  1. Water storage tanks with a capacity of 250 litres are 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 rusts 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 works 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.



Frequently Asked Questions

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.

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
  • The tank is manufactured from non-approved materials
  • Servicing/work carried out by an unqualified person will increase the risk of deterioration


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  • Lanark Office: +44 (0) 1555 664316
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  • Email: [email protected]

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