Underground Rainwater Harvesting Tanks

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Showing 49 - 58 of 58 products

Showing 49 - 58 of 58 products
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10000 Litre GRAF CARAT XL Direct Underground Rainwater Harvesting System (Home & Garden)10000 Litre GRAF CARAT XL Direct Underground Rainwater Harvesting System (Home & Garden)
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15000 Litre Underground Rainwater Harvesting Tank - Home + Garden15000 Litre Underground Rainwater Harvesting Tank - Home + Garden
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7500 Litre GRAF PLATIN AA-Silento Underground Rainwater Harvesting System7500 Litre GRAF PLATIN AA-Silento Underground Rainwater Harvesting System
7500 Litre GRAF PLATIN AA-Silento Underground Rainwater Harvesting System
Sale price£3,930.00 Regular price£5,400.00 exc. VAT
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15000 Litre Underground Rainwater Harvesting System - Garden Irrigation15000 Litre Underground Rainwater Harvesting System - Garden Irrigation
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10000 Litre Underground Flat/Shallow Dig Rainwater Tank - Graf Platin XL10000 Litre Underground Flat/Shallow Dig Rainwater Tank - Graf Platin XL
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10000 Litre GRAF PLATIN XL Garden Comfort Underground Rainwater Harvesting System (Garden Irrigation)10000 Litre GRAF PLATIN XL Garden Comfort Underground Rainwater Harvesting System (Garden Irrigation)
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10000 Litre GRAF PLATIN XL Direct Underground Rainwater Harvesting System (Home & Garden)10000 Litre GRAF PLATIN XL Direct Underground Rainwater Harvesting System (Home & Garden)
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10000 Litre GRAF PLATIN AA-Silento Underground Rainwater Harvesting System10000 Litre GRAF PLATIN AA-Silento Underground Rainwater Harvesting System
10000 Litre GRAF PLATIN AA-Silento Underground Rainwater Harvesting System
Sale price£5,417.40 Regular price£7,020.00 exc. VAT
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20000 Litre Underground Flat/Shallow Dig Rainwater Tank - Graf Platin XL20000 Litre Underground Flat/Shallow Dig Rainwater Tank - Graf Platin XL
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25000 Litre Underground Flat/Shallow Dig Rainwater Tank - Graf Platin XXL25000 Litre Underground Flat/Shallow Dig Rainwater Tank - Graf Platin XXL
Yes, many of our tanks, such as the Carat and F-Line series, can be made 'driveway-rated' by using a cast-iron lid and a reinforced concrete surround. This allows you to utilize the space under your parking area for water storage.
This depends on the tank. Our shallow-dig F-Line tanks only require an excavation depth of around 1 to 1.5 metres, whereas traditional round tanks may require 2.5 metres or more. Always check the specific installation manual for your model.
All underground harvesting tanks include an overflow pipe. This is connected to a soakaway or the main storm drain. We recommend using an overflow siphon with an integrated vermin guard to keep the system secure.
Harvested rainwater is non-potable (not for drinking). However, it is perfect for flushing toilets and feeding washing machines. This requires a dedicated plumbing circuit, and all pipes must be clearly marked (usually black with green stripes) to avoid confusion with mains water.
With a good pre-tank filter, you should only need to check the filter every few months and remove any leaf buildup. The tank itself generally only needs a visual inspection every 1-2 years and may only need a full clean-out every 10 years.
While the plumbing and electrical connections are straightforward for a competent DIYer, the excavation and backfilling usually require a groundworks professional or a mini-digger to ensure the tank is installed safely and according to the manufacturer's warranty.
Mains backup is a valve system that monitors the water level in your tank. If the rainwater reaches a critically low level, the system adds a small amount of mains water to the tank (or switches the feed directly) so your appliances always have a supply.
A common rule of thumb is to install the tank at a distance from the building that is at least equal to the depth of the excavation to protect the foundations. Most systems work efficiently up to 25 metres away using standard 25mm MDPE pipe.