With rainfall in the UK being 18 times the net consumption of the population, rainwater harvesting can provide a popular and viable environmental addition to our household water supplies. Most rainwater harvesting systems are designed for new builds, where there is clear ground and easy access, but they are rarely a practical option for established properties. Our systems are developed with the flexibility to cater for these differences as well as the requirements of the garden, to come up with solutions that actually work. Designed with the needs of the contractor in mind, our systems are made up of a series of top quality modular components that fit together, are easy to install and are targeted specifically for garden use.

The Garden Expert Package is the easy option to provide a sophisticated underground rainwater harvesting system targeted specifically for garden use. Based around the Graf Carat S tank, the package also includes a mini telescopic tank shaft and lid (suitable for pedestrian loading), a filter package 2 (with a calmed inlet and overflow siphon), a pump package 1 (with floating intake) and a hose connection box. As all our pump packages use intelligent demand-switched pumps, they will automatically start as soon as the tap is opened and will shut off when it is closed. The outlet from the tank can also be connected to an outside tap or standpipe to provide a pressurised source of soft rainwater or supply a simple tap-based irrigation system.

The 4-stage Cleaning Process: Stage 1 - The rainwater is first cleaned by a patented filter system positioned in the tank dome. As the water runs over the filter, the dirt and solids are caught in the filter basket and the clean water runs into the tank; Stage 2 - To allow the very fine particles to settle on the bottom of the tank, the filtered water is fed into the tank using a calmed inlet. This prevents permanent swirling of the water and also introduces oxygen to keep it clear; Stage 3 - Dirt particles, such as pollen, that are lighter than water settle on the surface of the water forming a floating layer. This floating layer is removed when the tank overflows and is washed away via the overflow siphon in the tank; Stage 4 - The collected rainwater is pumped out using a floating intake in the upper part of the tank. This takes the water from approximately 100mm below the surface - the site of the best quality water.

The Graf Carat S is unlike any other underground tank. It is the largest tank of its kind to be injection-moulded, resulting in a high quality engineered product that is consistent, strong and reliable. This process enables the Carat S to be manufactured as two easy to handle half shells, which can be stacked on top of each other for shipping, as well as saving space on site. The patented quick connection system, which has been laboratory tested to last more than 25 years, allows the tanks to be easily assembled (without any screws or bolts) in a matter of minutes, and uses a combination of a unique EPDM seal and sophisticated location pins. The ribbed design makes it light yet very strong and stable, enabling it to be installed in groundwater up to the middle of the tank.

The Carat S tank comes with a dome, which is designed to rotate independently of the tank, making it much easier to align the connections and pipes during installation. A dome extension is available along with a range of telescopic tank shafts with lids that are suitable for pedestrian and vehicle loading. These tank shafts slide up and down inside the dome offering adjustment for height as well as up to 5° of tilt, making it easy to get the lid flush with ground level.

These filter options fit neatly inside the dome of the Carat S tanks and come with 'Spannfix sleeves', which use Velcro for quick connection to the pipework. Filter package 1, which includes an overflow siphon with rodent guard and a calmed inlet, is suitable for rainwater that has been pre-filtered before it reaches the tank. The addition of a Graf Universal-Filter makes filter package 2 the recommended option for most underground systems. This has a removable filter basket and can manage roof areas up to a massive 350m². Filter package 3, which has a transparent lid for visibility and uses the self-cleaning Optimax filter, offers the best solution for low maintenance.

The tank connection kit uses special seals, which remain watertight even with slight tank misalignment

These easy to fit 110mm drainage pipes and fittings can be used to divert harvested rainwater to an underground tank, to connect tanks together and to run the overflow to a soakaway.

These modular tanks from Graf are designed to be connected together to make it easy to increase the storage area of your rainwater harvesting system, which is particularly beneficial where large volumes of water are required for irrigation. They are manufactured as two easy to handle half shells, which can be stacked on top of each other for shipping, as well as saving space on site. The patented quick connection system, which has been laboratory tested to last more than 25 years, allows the tanks to be easily assembled (without any screws or bolts) in a matter of minutes, and uses a combination of a unique EPDM seal and sophisticated location pins. The moulded design of the tank makes it light yet very strong and stable.

Each Herkules tank provides storage for 1600 litres of rainwater, and can be installed either above or below ground. By joining a number of tanks together, large volumes of water can be harvested, making them ideal for use with irrigation systems.

With each tank holding 1300 litres, the Top-Tank is designed for above ground use only, and like the Herkules, they can be easily joined together to provide substantial rainwater storage.

The Marley Waterloc system is the flexible option to provide sophisticated underground rainwater harvesting and is perfectly suited for garden use. Based around Marley’s Waterloc250 cells, it is a flexible modular system that stacks together in levels (inside a tough rubber liner) to create a tank in a range of length, width and depth options. The cells are cleverly designed to fit inside each other to save space during shipping, but by simply pulling them apart and turning them 180°, they stack on top of each other to create a tank with a void space of up to 95%.

To make life easier and ordering quicker, we have put together kits containing all the components required to install a Waterloc rainwater harvesting system, which includes fleece, liner, cell bases, cells, pipe connectors and the pump package. Simply choose the kit that matches the size of tank you require, taking into account the available space, the depth of the hole and the number of layers of cells. As all our pump packages use intelligent demand-switched pumps, they will automatically start as soon as the tap is opened and will shut off when it is closed. On a simple level, the outlet from the pump can be connected to our Plumb Your Garden range to provide a pressurised source of soft rainwater and to supply a simple tap-based irrigation system. Alternatively, it can be connected to a manifold of solenoid valves to create a large multi-zoned pop-up irrigation system.

These Mini Tower and Tower tank packages are the easy option to provide a sophisticated above ground rainwater harvesting system targeted specifically for garden use. As our pump packages all use intelligent demand-switched pumps, they will automatically start as soon as the tap is opened and will shut off when it is closed. The rainwater packages are designed to be connected to an outside tap or standpipe to provide a pressurised source of soft rainwater or to supply a simple tap-based irrigation system, while the irrigation packages have an upgraded pump to provide the improved pressure and flow required by larger irrigation systems.

The Mini Tower tank is a durable, premium quality rainwater storage tank with a fine textured finish, and comes in a range of colours to blend into its surroundings. The rugged Tower tank has a massive capacity of 1500 litres, and comes complete with a removable 460mm diameter lid to allow easy access for the pump. Both have a very small space-saving footprint and can be easily joined together (using the tank connection kits), allowing a large volume of rainwater to be stored in a small area, as well as providing the potential for future expansion.

These silt traps and filter options can be installed at any point on the inlet pipework upstream of the storage system and have a removable filter basket to protect the rainwater harvesting cells from the ingress of debris and silts.