GRPTanks
Corrosion-proof, long-life storage.
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Sizing, regulations, installation. Our team has been answering these questions for over 25 years.
GRP or Glass Reinforced Plastic is also commonly known as Fibre Glass. The GRP materials used in the manufacture of our tanks have been rigorously tested and approved for use in contact with potable (wholesome or drinking) water, providing confidence that the water is being stored in the optimum conditions, ensuring water quality of the highest standards.
Glass-reinforced plastic (GRP) has a number of advantages over other materials, such as Resistance to corrosion, lightweight, and High strength factor. If maintained correctly a GRP tank should have a lifespan of up to 25 years and within this time you won't need to worry about repainting or coating the tank during its lifespan. It is however important to note that it's good etiquette to have the tank inspected and disinfected annually to prevent any harmful bacteria from entering the water source for human consumption.
GRP cold water tanks are available as potable, one-piece, two-piece, and sectional water tanks, WRAS-approved water storage tanks. A vast range of tank accessories including float valves, overflows, outlets, level monitoring & level control equipment, tank foundations & support frames, ladders, drip trays, and more.
For peace of mind, we can offer commissioning on the GRP tanks.
GRP Tanks FAQs
What's the difference between a one-piece, two-piece and sectional GRP tank?
A one-piece tank is moulded as a single unit and is generally the most cost-effective option where access allows delivery of a complete tank. Two-piece tanks are joined on site with a sealed flange, useful where access is tighter but a crane or lifting gear can still get the halves in. Sectional tanks are built up from individual panels bolted together inside the building, making them the only practical option for large capacities or restricted access such as plant rooms and roof spaces.
Is a GRP tank suitable for storing drinking water?
Yes, provided the tank is manufactured from WRAS-approved materials and fitted with the correct WRAS-approved fittings such as float valves, overflows and inlets. Our potable GRP tanks are specifically designed and tested for contact with wholesome water, so water quality isn't compromised. Always check the tank's WRAS approval status before connecting it to a drinking water supply.
How do I work out what size GRP tank I need?
Sizing depends on the application — domestic cold water storage is typically based on daily household demand plus a reserve, while fire suppression or agricultural use will have their own calculation methods. As a guide, a typical UK household uses around 150 litres per person per day, but you should also factor in peak demand and any backup requirement if mains supply is interrupted. If you're unsure, get in touch with our team with your usage figures and available installation space and we can help you select an appropriate capacity.
What foundation or support does a GRP tank need?
GRP tanks need a firm, flat, level base capable of bearing the full weight of the tank when filled with water, as an uneven surface can cause stress cracking over time. For ground-level installation this is typically a concrete slab or compacted hardcore base, while elevated or roof-mounted tanks require a proper steel support frame rated for the filled weight. We supply tank foundations and support frames designed to match our tank ranges, so it's worth specifying these together.
How often does a GRP water tank need inspecting or cleaning?
It's good practice to have potable water tanks inspected and disinfected annually to prevent bacterial growth, sediment build-up or biofilm forming, particularly on systems supplying drinking water. This is a straightforward job for a qualified water hygiene contractor and helps maintain compliance with water quality regulations. Regular inspection also lets you catch any fitting or seal issues early, well before they become a bigger problem.
What accessories will I need alongside a GRP tank?
Most installations need, at minimum, a WRAS-approved float valve to control filling, an overflow with insect-proof screening, and an outlet fitting sized to your pipework. Depending on the application you may also want level monitoring or control equipment, access ladders, drip trays to catch condensation or minor leaks, and a support frame or foundation base. It's worth speaking to us before ordering so the tank and accessories are specified as a matched set.