“WRAS approved”, “NSF certified”, “BS EN 13280” — these terms appear in almost every water tank quotation, and they are frequently used to mean something they do not. A standard that covers a product’s dimensions is not the same as a certification for contact with drinking water, and a certificate for one component is not a certificate for the assembled tank.

This article explains what the main standards and approval schemes actually cover, what a supplier can legitimately claim, and what to ask for when compliance matters. It is written from the perspective of a water tank manufacturer who has to produce this documentation for every project.

Two Different Things: Product Standards and Potable Water Approval

The confusion starts here, so it is worth separating the two categories clearly.

• Product standards describe how a tank should be made — materials, dimensions, structural requirements, testing. They define what the product is.
• Potable water approval covers whether the materials in contact with drinking water are safe — that they do not leach harmful substances or taint the water. It defines whether the product is acceptable for that use.

A tank can meet a product standard perfectly and still be unsuitable for drinking water if the resin or coating is not approved. It can also carry a potable water approval for its materials and still be built badly. Both matter, for different reasons.

Product Standards Commonly Referenced

These are the standards a competent supplier should be able to reference specifically — not as a badge, but as a description of how the tank was specified.

Potable Water Approval Schemes

Approval for drinking water contact is usually handled by a national scheme, and the material or product is tested and listed. Three schemes appear most often in international specifications:

• WRAS (Water Regulations Advisory Scheme), UK — approval of materials and fittings for use in contact with wholesome water in the UK. A WRAS approval is granted to a specific material or product, so it is important to confirm exactly what is covered.
• NSF/ANSI 61, North America — drinking water system components: health effects. It addresses the leaching of contaminants from materials in contact with drinking water.
• National equivalents in other markets — many countries operate their own approval lists, and some accept a WRAS or NSF/ANSI 61 listing as evidence, while others require local approval.

The practical point is that approval is jurisdiction-specific. A tank certified in one market is not automatically acceptable in another; the project specification should state which approval is required.

What to Ask Your Supplier For

• The specific certificate — not a logo on a datasheet. Ask which product or material the listing covers, and its reference number.
• Scope of approval — in particular, whether the internal gel coat or lining is covered, and whether the sealant and any internal fittings are included.
• Sub-components — anti-vortex fittings, gaskets, level controls and internal fixings all contact the water. Confirm they are approved too.
• Manufacturing consistency — a certificate applies to the material as produced; confirm the production process is controlled and that the certificate is current.
• Declaration of conformity — a signed statement for the project file, covering the tank as supplied for that order.

Beyond Certification: Design Requirements for Potable Water

Meeting the material certification is necessary but not sufficient. Good practice for potable water storage also requires:

• Sealed and screened — the tank must exclude insects, birds, rodents and light, with a close-fitting lockable cover and screened vents.
• No stagnation — the inlet and outlet arranged so stored water turns over rather than short-circuiting, and the volume kept in proportion to daily demand.
• Backflow protection — an air gap or approved backflow prevention device between the tank and any source of contamination.
• Access for cleaning — a manway of adequate size, and internal surfaces that can be cleaned without damage.
• Commissioning and sampling — chlorination, flushing and bacteriological testing before the tank enters service.
• Documented maintenance — the cleaning and inspection regime that keeps the approval valid in practice.

Our potable water tank range is specified with certified food-grade materials, sealed access and screened vents as standard, and is supplied with the documentation set a project file normally requires.

Common Misunderstandings

• “It is GRP, so it is food safe.” — Only if the resin and gel coat are certified for the purpose. Not all GRP is.
• “The panel is approved, so the tank is approved.” — Fittings, sealant and internal components also contact the water.
• “Stainless steel needs no approval.” — The grade matters, and some stainless steel surface treatments or weld consumables can affect water quality.
• “Approved once, approved forever.” — Certification is tied to the certified material and production process, and to the tank’s maintained condition in service.

Frequently Asked Questions

Is GRP suitable for drinking water storage?

Yes, when the panels are manufactured with food-grade resin and gel coat and carry an appropriate approval such as WRAS or NSF/ANSI 61. This should be stated explicitly in the specification, because it is a material choice rather than an automatic property of GRP.

Which is better for potable water — stainless steel or GRP?

Both are well established. Stainless steel offers a non-porous surface that is easy to sanitise; certified GRP offers the same suitability at lower cost and without the risk of chloride pitting. For most commercial installations both are acceptable, and the deciding factors are cost, environment and specification preference.

Does a certificate expire?

Approval listings are periodically reviewed and can be withdrawn if a material or process changes. Always request a current certificate rather than an older copy from a previous project.

What if my country has no national approval scheme?

Many projects accept a WRAS listing, an NSF/ANSI 61 certification or a recognized independent laboratory test as evidence of suitability. State the required evidence in the tender documents so all suppliers answer the same question. Any experienced FRP water tank manufacturer will already know which scheme their product holds and what it covers.

Summary

Product standards define how a tank is built; potable water approvals determine whether its materials are safe for drinking water. Specify both, ask for the actual certificates and their scope, and remember that certification only holds if the tank is designed for good turnover and maintained properly in service.

Need documentation for a potable water project? Contact us and we will supply the material certifications, declarations and design details your specification requires.