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.

maxima system
Top-of-the-range easy-fit 'plug 'n' play' system.
Use Me For
Maxima light commercial rainwater system

RainSava® Maxima

The RainSava® Maxima rainwater harvesting system is suitable for large domestic properties or smaller commercial installations. Another excellently designed product from leading German manufacturers; WISY AG. The system is designed for plant room or basement installation and can be connected to above or below ground tanks. It’s compact design and very small footprint enables it to be used in spaces where other units simply won’t fit.

Water is pumped from the main storage tank to the Maxima unit and then fed to the desired outlets using a submersible pump (housed inside the Maxima). Mains water top up is to the Maxima so there is no need to top up the main rainwater tank, this is highly advantageous for installations with very large tanks or where an above ground tank is being used.

Large domestic or light commercial

The unit is a state of the art plug and play rainwater system designed for larger homes or for light commercial use, e.g. industrial units, small visitor centres etc.

  • Low energy (0.2 watt standby power)
  • Plug and play technology
  • 100L break tank with internal pump
  • Dedicated Pump and Controller for better reliability
  • Self contained system
  • Stainless steel high quality pump
  • Mains water top up with AA air gap

Typical Applications:

  • Large domestic properties
  • Small commercial Rainwater Harvesting
  • Retro-fit rainwater systems
  • Basement installations
  • Above ground storage tanks
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 system is based around the Maxima rainwater centre; this is a compact 100L buffer tank with a very small footprint and housing a submersible pressure pump. Additionally there is a second pump located in the main storage tank, which supplies water on demand to the Maxima unit. If no rainwater is available, then the Maxima is automatically filled from the mains water supply. The integral control panel controls both pumps and the mains water feed, and provides dry-running protection

RainSava® GRP tanks

UK made tanks manufactured to BS 4994 from high grade GRP; 100% glass fibre / rising 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.