Read more about the importance of filtration in a rainwater harvesting system

Read more about the water quaity from of our rainwater harvesting systems.

Not sure which tank you need?
Use our calculator to find out.

Learn about looking after a rainwater harvesting system.

RainSava Gravity
Low pressure header tank system
Use Me For
Rainsava gravity system diagram
  • Low energy (as low as £3 per house per year)
  • Easy maintenance (filter is accessible from ground level)
  • BS8515 compliant (tank is fitted with an anti backflow and rodent guard)
  • Dedicated Pump and Controller for better reliability
  • Option of manual valves in Headertank – no power required to loft.
  • Stainless steel High quality pump
  • Cleanest water possible due to:
    • Advanced Wisy Vortex filtration removing debris without allowing it to degrade on a horizontal filter mesh
    • Pre-tank Filtration to 0.28mm
    • Floating suction set with 0.3mm mesh filter
0.2mm Fine Mesh Filter
0.28mm Mesh Filter
BS8518 Compliant Rainwater systems
BS8518 Compliant
Easy to clean filter
Easy to Clean
Energy saving rainwater system
Energy Saving

The RainSava Indirect system offers the best in current pump technology, energy efficient pump controlling, and reliability. Water is filtered and collected in the main tank and pumped to the headertank where it is gravity fed to the appliances when needed.

In the event that there is no water in the main rainwater tank, or in the unlikely event that there is a power cut, the mains water feed to the header tank opens mechanically to allow uninterrupted supply to appliances.

RainSava® GRP Tanks

UK made tanks manufactured to BS 4994 from high grade GRP; 100% glass fibre / resin mix with no fillers. These tanks are manufactured to our own specification to comply fully with BS 8515. This includes our unique Multisiphon overflow trap with built-in backflow protection.

Note: It is a requirement of the British Standard for rainwater harvesting that all rainwater tanks are protected against backflow. Most tanks are supplied without this feature, so it has to be added by the installer downstream of the tank itself. Our RainSava® tanks are always fitted with backflow protection.

Tank Volume (Litres)Nominal length (mm)Nominal diameter (mm)Weight (kg)
15001600122090
200021001220130
240023501220150
300020001520180
350023001520190
400026001520200
500030801670240
600027001840260
750033501840300

Other sizes are available, including large tanks for commercial projects up to 100,000 litres.

NB. All GRP tanks are built to order with the ability to have the inlet invert as deep as 1.2m, but can be made to accommodate greater depths if necessary. Before ordering a tank, check what depth your inlet will be to make sure the tank is correct for your installation. Tank necks can always be cut down on site if needed.

HINT: It is good to be shallow with the tank, but the pipe depth is governed by the location of the tank and distance the pipes have traveled in the ground rather than the type of tank. Most UK water pipes are buried at 600-900mm.

Low Profile Shallow-Dig Tanks

In some situations it may be desirable or beneficial to use a shallow tank (e.g. in high groundwater conditions or hard rock ground). For these installations we offer a range of low-profile tanks. These are excellent for certain situations, but are manufactured from a costlier material and imported from Germany so are naturally more expensive.

Also note that these tanks do not include backflow protection, unlike our GRP tanks.

Tank Volume (Litres)Nominal length (mm)Nominal width (mm)Nominal height (mm)Weight (kg)
15002400120073580
300024002400735160
5000296022201035250
7500334023101240310

Read more about the importance of filtration in a rainwater harvesting system

Read more about the water quaity from of our rainwater harvesting systems.

Not sure which tank you need?
Use our calculator to find out.

Learn about looking after a rainwater harvesting system.