WaterTanks

GRP (glass reinforced plastic/fibreglass) tanks are typically used for larger sectional installations, offer excellent structural strength and can be built or extended on site for awkward access points. Polyethylene tanks are moulded in one piece, generally lighter and more cost-effective for smaller to mid-size capacities, and are the more common choice for domestic installations. Both are suitable for potable water storage provided they carry WRAS approval.

Above ground tanks are cheaper to install, easier to inspect and maintain, and suit sites with space to spare. Underground tanks keep water cooler and out of sight, free up land above for other use, and are better protected from frost and UV degradation, but need proper excavation, backfill and access covers. Ground conditions, water table and access for delivery vehicles all affect which option is practical on your site.

For domestic potable storage, allow roughly 200 litres per person per day as a guide, then factor in how many days of backup supply you want. For rainwater harvesting, size against roof catchment area and intended use — garden irrigation needs less buffer than a system also flushing toilets. If you're unsure, tell us your household size or application and we can help you work out a sensible capacity.

Underground tanks and any associated pipework typically fall under building regulations, particularly where they connect to a potable supply or drainage system, so building control should be notified. Above ground tanks are generally more straightforward but still need to meet WRAS water regulations if supplying drinking water. It's worth checking with your local authority before installation, especially for larger commercial systems.

No — rainwater harvesting tanks are non-potable and designed for uses such as toilet flushing, garden irrigation, washing machines or vehicle washing. Turning harvested rainwater into a drinking supply would require additional filtration and disinfection well beyond what these tanks are built for. Keep harvesting systems clearly separate from your potable mains supply to avoid cross-contamination.

Confirm access for the delivery vehicle, particularly for larger GRP sectional tanks or IBCs, as narrow gateways or overhead cables can cause problems on the day. Make sure the base or foundation is prepared in advance — a level, load-bearing plinth or slab appropriate to the tank's filled weight is essential. If the tank is going underground, excavation and any backfill material should be ready so installation isn't delayed.