What is WRAS Approval? UK Drinking Water Compliance for Large-Scale Commercial and Industrial Water Storage Tanks

Any tank, fitting, or component connected to the mains water supply in the UK must comply with the Water Supply (Water Fittings) Regulations 1999. These regulations exist to protect public drinking water from contamination and to prevent waste, misuse, and undue consumption of water from the public mains. WRAS approval is the certification scheme that confirms a product meets those requirements, and it applies to everything from a domestic tap to a large-scale commercial or industrial water storage tank.

For facilities managers, water utility operators, and commercial site operators specifying large-scale potable water storage, understanding what WRAS approval is and what it requires is not optional. It is a legal duty on everyone involved in the specification, installation, and use of mains-connected water fittings and storage systems. Butek Tanks' corrugated steel water storage tanks, fitted with WRAS-approved liner kits, are the specification trusted by water utility companies, local authorities, and food production facilities across the UK precisely because every component in contact with the stored water has been independently tested and approved.

What is WRAS Approval?

WRAS stands for the Water Regulations Advisory Scheme, formally known as Water Regulations Approval Scheme Ltd. It is a UK certification body that tests and approves water fittings and materials for compliance with the Water Supply (Water Fittings) Regulations 1999. A product that carries WRAS approval has been independently tested and confirmed to meet the standard required for use in contact with drinking water in the UK.

WRAS approval applies to any water fitting: taps, valves, pipes, tanks, liners, seals, and any other material or component that comes into contact with water intended for human consumption. The scope covers both the materials used in construction and the performance of the fitting under normal operating conditions. A water storage tank used for potable water must be WRAS-approved not just in its outer shell but in every component that contacts the stored water, including the liner itself.

WRAS approval is not the same as NSF certification, which is the equivalent standard used in North America. For UK mains-connected installations, WRAS approval is the required certification. NSF certification does not satisfy the requirements of the Water Fittings Regulations in England, Wales, or Scotland.

Why WRAS Approval Exists: The Legal Framework

The Water Supply (Water Fittings) Regulations 1999, which replaced the earlier water byelaws, set out the legal framework governing all water fittings connected to the public mains supply in England and Wales. Scotland operates under the Scottish Water Byelaws 2014, and Northern Ireland under NIEA regulations, but the core principle is consistent across all four nations: fittings connected to mains water must not contaminate, waste, misuse, or cause undue consumption of water from the public supply.

The Regulations create a legal duty on everyone involved in the installation and use of water fittings. This includes the retailer or plumber who installs the fitting, the business that specifies it, and the organisation that uses it. Ignorance of the requirement is not a defence. If a non-compliant fitting is installed and causes contamination of the mains supply, enforcement action and liability fall on those responsible for specifying and installing it.

The reason contamination is treated so seriously is straightforward. Non-compliant materials in contact with drinking water can leach chemicals into stored water, affect the smell of drinking water, and promote the growth of microorganisms including Legionella and other pathogens. Backflow from a non-compliant storage system can carry contaminated water back into the public mains, putting a much wider population at risk.

What WRAS Approval Covers in a Water Storage Tank System

For large-scale commercial and industrial water storage, WRAS approval must cover the full installation, not just the tank shell. Every component in contact with the stored potable water must be independently assessed and approved. In a corrugated steel tank system, the liner is the most critical component.

The liner sits inside the steel tank and forms the watertight chamber that actually contacts the stored water. For potable water use, the liner must be manufactured from WRAS-approved materials that will not contaminate water, will not support microbial growth, and will not degrade under normal storage conditions over the expected service life of the installation. Our WRAS-approved liner kits are manufactured in-house and are the correct specification for any corrugated steel tank storing drinking water or mains-connected water supplies.

Beyond the liner, the valves, fittings, and connections used on the tank must also comply with the Water Fittings Regulations. This includes inlet valves, outlet valves, overflow fittings, and any draw-off point. Our tank accessories range covers gate, ball, and butterfly valves in all sizes, specified to match the application and the stored liquid. Roof kits are equally important: an open or poorly covered potable water tank is vulnerable to airborne contamination, bird access, and UV-driven algal growth. A correctly specified roof cover is part of any compliant potable water storage installation.

WRAS Approval and Plumbing Systems: From Domestic to Large-Scale Commercial

WRAS approval applies equally to plumbing systems in homes and to large-scale commercial and industrial storage. The same Water Fittings Regulations govern both. The scale of the installation does not change the legal requirement. What changes is the complexity of demonstrating compliance and the consequences of non-compliance.

For a domestic plumber fitting a replacement tap, WRAS compliance is typically handled through product selection. For a commercial operator specifying a 500,000-litre potable water storage tank for a water utility, hospital, or food production facility, demonstrating compliance requires documentation of every component, the liner material, the installation method, and the ongoing maintenance regime.

UK regulations also specify that suitable water fittings must be used at all points of contact and that the system as a whole must not contaminate the water. This is why whole-system compliance, rather than component-by-component checking, is the correct approach for large-scale installations. Professional tank installation services with full handover documentation of WRAS-compliant components give commercial operators the audit trail they need for regulatory and insurance purposes.

How to Verify WRAS Approval

WRAS maintains a publicly accessible approved products register on the WRAS website. Any product or material that has been tested and approved carries a WRAS approval number that can be verified against the register. When specifying tanks, liners, or fittings for potable water use, always request the WRAS approval number and verify it before installation.

For bespoke or large-scale storage systems where individual components may have been approved separately, it is the responsibility of the specifier to confirm that every element in contact with UK water is covered. If a component is not on the approved products register, it should not be used in a mains-connected potable water installation.

WRAS approvals are time-limited and must be renewed. Manufacturers are responsible for maintaining approval status. Specifiers should verify the current status of any product's approval at the time of installation, not just at the time of initial specification. Where a product has not previously been approved, the manufacturer must submit it for testing, and if the initial submission does not pass, they can resubmit after making the necessary changes.

Non-Metallic Materials and Why They Matter for Potable Water Tanks

Non-metallic materials including rubber liners, plastic fittings, sealants, and coatings that contact drinking water are subject to particular scrutiny under the WRAS approval process. The risk from non-metallic materials is significant because they can leach chemical compounds into stored water and may promote the growth of microorganisms if not manufactured to the approved specification.

For agricultural operations requiring both potable water storage and non-potable liquid storage on the same site, it is essential that both supplies are stored in clearly labelled, physically separate tanks. Slurry tanks and trade effluent storage must never share infrastructure with potable water systems. Our team designs multi-tank sites to ensure compliant separation from the outset, protecting both the potable supply and the operator's regulatory position.

The Byelaws 2014 in Scotland and equivalent regulations elsewhere reinforce the same principle: components and materials used in contact with mains water must be approved and fit for purpose, and the installation conditions under which approval was granted must be followed in the field.

Frequently Asked Questions About WRAS Approval

Does every water storage tank need WRAS approval?

Any tank connected to the mains supply and used to store water intended for human consumption must comply with the Water Fittings Regulations 1999, and every component in contact with the water must be WRAS-approved. Tanks used for non-potable purposes that are not connected to the mains supply do not require WRAS approval, but must be clearly labelled as non-potable and kept physically separate from any potable supply.

What is the difference between WRAS approval and the old byelaws?

The Water Supply (Water Fittings) Regulations 1999 replaced the old water byelaws in England and Wales. WRAS approval is the modern certification route confirming compliance with the 1999 Regulations. Any new product or installation must comply with the current Regulations rather than the superseded byelaw standards.

Does WRAS approval apply to the liner inside a steel tank?

Yes. The liner is the component that directly contacts the stored drinking water and it must be manufactured from WRAS-approved materials. This is one of the most frequently overlooked compliance points on large-scale storage installations. A steel tank shell that is structurally certified but fitted with a non-approved liner does not meet the requirements of the Water Fittings Regulations for potable water use.

Is WRAS approval valid indefinitely?

No. WRAS approvals are time-limited and must be renewed by the manufacturer. Specifiers should verify the current approval status of any product at the time of installation rather than relying on historical documentation.

Need a WRAS-Compliant Potable Water Storage Tank?

Whether you are specifying a new potable water storage system, upgrading an existing installation to meet current Water Fittings Regulations, or managing a large multi-tank site, Butek Tanks provides bespoke corrugated steel water tanks with WRAS-approved liner kits for every potable water application. Our tanks are ISO 9001:2015 certified, CE marked, and trusted across the UK water industry.

Call us on +44 (0)1277 653 281, email enquiries@butektanks.co.uk, or visit our contact page to discuss your requirements.