PotableWater Tanks

WRAS approval confirms a tank and its fittings have been tested and listed as suitable for contact with wholesome water under UK Water Regulations. It means the materials won't taint, discolour or contaminate the water, and won't support bacterial growth. Always check that the tank itself, plus any fittings and seals supplied with it, carry this approval — not just the main vessel.

Most potable tanks are made from either polyethylene (plastic) or GRP (fibreglass), both manufactured using food-grade, WRAS-approved materials. Polyethylene tanks are lighter, cost-effective and suit smaller to mid-sized installations, while GRP tanks offer greater structural strength for larger capacities and above-ground applications. Stainless steel is another option where durability and a long service life are priorities.

Sizing depends on daily consumption, number of occupants or users, and whether the tank is a sole supply or backup storage. As a rough guide, domestic properties often work on 90–150 litres per person per day, then factor in a buffer for outages or peak demand. For commercial, agricultural or community supplies, it's worth speaking to our team so we can help match capacity to actual usage patterns.

Yes, many potable tanks are designed for underground installation, which keeps water cool and protected from light — both important for maintaining water quality. Below-ground GRP and polyethylene tanks need correct backfill, groundwater consideration and adequate access covers for inspection and maintenance. Always check the manufacturer's installation guidance, as underground fitting incorrectly can void warranties and affect structural integrity.

Yes, potable tanks must have insect-proof, light-excluding covers and vents to stop contamination while still allowing air displacement as water levels change. Light exclusion is essential to prevent algae growth inside the tank. Access points should be secured to prevent unauthorised entry or debris ingress, particularly on tanks used for private drinking water supplies.

Larger potable tanks are bulky items, so check access routes, ground conditions and whether you'll need offloading equipment such as a forklift or crane on delivery day. For underground tanks, groundworks and excavation need to be completed and ready in advance to avoid delays. It's also worth confirming lead times with our team, as larger or bespoke capacities can take longer to manufacture than stock sizes.