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13,000-Liter Underground Tank System – Rainwater Storage System Consisting of 2 Tanks

Large Storage Capacity for Underground Rainwater Storage

The GreenLife underground tank system, with a total capacity of 13,000 liters, consists of two round tanks, each with a capacity of 6,500 liters. It is ideal for anyone who wants to store large quantities of rainwater underground and put it to use. The cistern duo can be used for garden irrigation, household rainwater reuse, larger properties, outdoor facilities, agricultural applications, and commercial areas with high water demand.

The two tanks are delivered pre-assembled and ready for connection. The system includes two height-adjustable sliding domes with walk-on safety covers. Depending on your needs, the underground tank system can be configured without accessories or equipped with a factory-installed inlet flow stabilizer, a tank-mounted filter with inlet flow stabilizer, or a Biovitor.

Using the rainwater calculator, you can determine the appropriate storage capacity based on your property, roof area, and usage requirements.

Product Features and Benefits

  • Pre-assembled system components—two 6,500-liter tanks with two sliding domes, two covers, and a pre-prepared bottom connection
  • Height-adjustable sliding domes – each extendable by 200 mm and tiltable up to 5° to adapt to the ground level
  • Seamlessly manufactured—monolithic tank bodies produced using the rotational sintering process, featuring a stress-free design and permanent leak-tightness
  • Optimized tank structural integrity—reinforced beading profile supports the containers’ dimensional stability
  • Walk-on safety covers—non-slip, rated for up to 200 kg, and child-proof lockable with stainless steel screws
  • Three pre-assembled connections—DN 100 with rubber lip seals for inlet, overflow, and supply or empty pipe connections
  • Additional connection points – can be drilled to custom specifications for future system expansions
  • PE and 100% recyclable – durable, corrosion-resistant, and opaque material
  • 25-year warranty—provided the unit is installed properly in accordance with the installation instructions; the warranty certificate (DE) is available for download

Equipment Options

You choose the right configuration for your underground tank system. The components are pre-assembled at the factory.

  • Without accessories—for customizing or expanding your system
  • With an inlet flow stabilizer – stabilizes the water inflow and reduces turbulence in the tank
  • With an in-tank filter and inlet stabilizer – for pre-filtering rainwater directly in the tank
  • With Biovitor – biological water treatment without the use of chemicals and integrated inlet flow stabilizer

Technical Specifications

Material Polyethylene
Volume 13,000 liters
Weight 520–530 kg, depending on the configuration
Length 2,300 mm
Width 5,250 mm
Overall height 2,720–2,920 mm, retractable sliding domes
Connections 3 × DN 100 (Ø 110 mm) with rubber lip seals

Installation & Use

Delivery within mainland Germany is free of charge via a freight carrier, delivered curbside. For information on the exact delivery process, see “Delivery Process.”

Please follow the installation instructions and read all instructions carefully and in full before installation, connection, and commissioning. Safety and installation regulations must be observed to ensure proper installation and safe use.

For round tanks, dig deeper rather than wider. If groundwater or perched water is present, take appropriate precautions (see installation instructions) or, alternatively, use flat tanks.

For installation under areas accessible to passenger cars, a cover suitable for passenger car traffic is required. For areas accessible to trucks, the truck-traffic kit is required.

Improper installation or failure to follow the installation instructions may void warranty and guarantee claims, particularly if a defect is attributable to faulty installation. Check the system regularly for leaks, cleanliness, and stability.

Materials & Sustainability

The underground tank system is made of durable and 100% recyclable polyethylene (PE). Some of the material used comes from our own recycling program. The robust construction is designed for reliable use over many years, thereby supporting resource-efficient operation.

The polyethylene used is chemically inert and has no effect on the quality of the stored rainwater. The system’s full recyclability and the use of material from our own recycling program support the circular economy. GreenLife manufactures the underground tanks in Germany. Learn more about sustainability at GreenLife.

Characteristic Value
Material Polyethylene
Volume 13,000 liters
Weight 520 kg
Length 2,300 mm
Width 5,250 mm
Overall height 2,720–2,920 mm, retractable sliding roof
Connections 3 × DN 100 (Ø 110 mm) with rubber lip seals
Vehicle Accessibility With a cover suitable for passenger car traffic and in accordance with the installation instructions
Truck traffic capability With a kit for truck traffic and in accordance with the installation instructions
Backfill As per installation instructions
Recyclability 100%

Do You Have Any Questions? We’re Here to Help.

Our customer service team is happy to assist you with any questions regarding product selection, application, installation, or accessories.

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Accessories

filterkorb zisterne
Cistern filter basket 300

DetailsFor filtering rainwater. The filter features a filter basket with a mesh size of approx. 1 mm. Rainwater is fed in via a 300 mm long PE pipe DN100 (Ø110). The pipe can be shortened. The cistern filter basket is easy to retrofit and can be removed effortlessly for cleaning.Technical DataFilter basket material: PolyethyleneFilter basket height: 240 mmFilter basket diameter: 300 mm

Regular price: €79.00
Domverlängerung für wassertank
Dome extension DN 600 (from 03 2021)

DetailsThe DN 600 dome extension is compatible with the expansion and sliding domes from 03/2021Please contact us so we can assist you with advice!

Regular price: €99.00
starterset versickerung regenwasser
205-Liter Infiltration Starter Kit with Geotextile

Set including a 205-liter infiltration cube and 4 m² of geotextile for the subsurface infiltration of rainwater and treated wastewater.

Regular price: €99.00
Wasseranschlussbox
Water connection box
Color: moss green

DetailsConnection box for installing hose connections. It is inserted into a DN100 conduit, through which the water supply line also runs. A cover flush with the ground surface protects the connections. Technical Data Weight: 1.85 kgColor: greenDiameter: 288 mmTotal height: 248 mmConnections: 1/2" and 3/4"

Regular price: €75.00
zapfsäule garten
Garden tap, antique
Color: granite gray

Antique Garden Water Faucet – Stylish Water Access in the Garden Rustic stone look. Practical water access. Charming integration. The antique-style garden water spout offers a decorative and functional way to draw rainwater directly in the garden. It is freestanding and available in a stylish granite look in several colors—ideal for anyone who wants to combine design with practicality. Your benefits at a glance Antique stone look – harmoniously integrated into natural and garden areas Freestanding – quick to install and secure to set up Child-safe – Sturdy faucet includes a removable key UV- and weather-resistant PE plastic – durable, weatherproof material Compatible with rainwater harvesting – easy connection to tanks, storage tanks, or cisterns Made in Germany – high-quality workmanship, sturdy and easy to maintain Even easier for you: service & consultation included Expert advice on optimal placement, connection, and combination with pumps or tanks Reliable delivery within Germany Spare parts service – faucets, wrenches, and gaskets available for reorder even long-term Sustainability with responsibility Made from single-material, 100% recyclable polyethylene, the water dispenser is free of plasticizers and PVC. It supports rainwater harvesting and conserves natural resources—a stylish solution with a sense of responsibility. Applications Private gardens and patios – attractive and functional Community and school gardens – durable and child-safe Landscaping and horticultural projects – decorative with practical benefits Green spaces – durable water feature with design appeal Do you have questions? We’re here to help. Our customer service team is happy to assist you with any questions regarding installation, technology, and rainwater harvesting. Phone: 0385 / 773370 Email: info@greenlife.de

Regular price: €129.00
Gartenzapfsäule Ebenholz – Moderne Wasserzapfsäule
Garden dispenser, modern
Color: ebony

DetailsThe garden water dispenser is a freestanding column with a faucet. It can be bolted to a solid surface or placed directly into the ground. The rainwater supply line is connected at the bottom of the rear. A spout with a removable control key is included.We recommend combining it with the GAP X80 or GAP X120 automatic rain barrel pumpTechnical SpecificationsMaterial: PolyethyleneColor: EbonyWidth: 107 mmDepth: 107 mmHeight: 1030 mm

Regular price: €69.00
Gartenzapfsäule Sandbeige– Moderne Wasserzapfsäule
Garden dispenser, modern
Color: sand beige

DetailsThe garden water dispenser is a freestanding column with a faucet. It can be bolted to a solid surface or placed directly into the ground. The rainwater supply line is connected at the bottom of the rear. A spout with a removable control key is included.We recommend combining it with the GAP X80 or GAP X120 automatic rain barrel pump.Technical SpecificationsMaterial: PolyethyleneColor: Sand beigeWidth: 107 mmDepth: 107 mmHeight: 1030 mm

Regular price: €69.00
Tauchdruckpumpe GAP X120
Automatic submersible pressure pump GAP X120 with lateral suction and integrated automatic switch

Specifications at a glance:Max. Delivery rate/flow rate: 100 l/min (6.0 m³/h)Max. Head: 45 m / Pressure: 4.5 barConnection sizes: 1" (inch) F (female thread)Power cord length: 15 mSuitable for: Rainwater harvesting, via side intake: floating extraction of clean water from below the water surfaceMax. immersion depth: 12 mHigh-performance submersible pressure pump for versatile applications Our automatic GreenLife GAP X120 submersible pressure pump is a modern, powerful, and reliable submersible pressure pump. It handles large flow rates with ease and is suitable for a wide range of applications, such as water supply and drainage tasks in clear water. The pump automatically regulates the water flow based on the user’s water demand. Examples of applications:  Extraction of rainwater from rainwater systems, tanks, and cisternsUse of clear water inside or outside a buildingIrrigation of a lawn or gardenOperation of sprinklers or sprayers (on average, three sprinklers can be operated simultaneously)Draining or pumping water, for example from poolsDomestic water supply Operation / Performance: The pump is fully submersible and is immersed in the water. The maximum immersion depth is 12 meters. The pump automatically controls water delivery when the line to the consumer is open (faucet open). When the consumer is closed, the pump switches to standby mode. The pump is then in start/stop mode and maintains pressure in the line. When the consumer is opened again, the pump restarts and delivers water.  The GAP X120 has a maximum flow rate of 100 liters per minute and a maximum head of 45 meters. This extremely high-pressure pump, with a maximum of 4.5 bar, enables effortless and effective irrigation. The power consumption (P1) is 1.15 kW. A built-in thermal motor protection prevents overload and ensures automatic restart after cooling down. Optionally, a pump base with side suction can be mounted for floating intake. This allows clean water to be drawn from below the water surface, not from the bottom. Quality: The use of stainless steel and high-quality plastic ensures a long service life. An integrated dry-run protection shuts off the pump in case of water shortage. A practical handle makes transporting the pump a breeze. With an IP 68 protection rating, the pump is dust- and waterproof. Conclusion: With the GAP X120 submersible pressure pump, you are purchasing a modern, automatic pump that switches on and off automatically according to water demand, features dry-run protection and thermal motor protection, and is suitable for both side and floating suction. Additional Features & Notes: Do not pump saltwater, wastewater, corrosive, highly flammable, or explosive substances (e.g., gasoline, kerosene, nitro thinner), oils such as heating oil and vegetable oils, or food! The water temperature must not exceed 35°C. An integrated, easy-to-clean stainless steel suction filter provides optimal protection against debris.Please note that (as described in the installation and operating instructions) this is a clear water pump that must only pump clean water—ideally pre-filtered with the Biovitor—to remain fully functional.  You also have the option of using the pump base if the pump is placed on a surface rather than suspended (see installation instructions). Maintenance and Installation Instructions: If there is a risk of frost, drain the pump and store it in a frost-free location. Please follow the installation and operating instructions. Do you have questions about this pump or other rainwater harvesting products? Our customer service team is here to provide expert assistance: 0385 77 337 72 (weekdays 8 a.m.–4 p.m.). Our service promise: In the event of a repair, we will send you a free return label for shipping via DHL to our factory—during the 24-month statutory warranty period. Scope of delivery:  GAP X120 submersible pump complete with connection cable and Schuko plug (cable length 15 meters)Additional pump base with 1-inch external thread on the side90° elbow (1-inch with female thread)Stainless steel suction filter (1-inch male thread; replace the pump base to install the suction filter)Double nipple (1-inch, for screwing in the hose connection nozzle)2 hose connection fittings, each 1 inch & ¾ inch with union nut (incl. 2 gaskets)Clamp (31–34 mm)Rope (for suspending the pump and for easy removal from the cistern)Installation and operating instructions Delivery of this product via parcel service Looking for a different pump...?AMIGA MH1100 4M Pump ... a dry-mounted pressure pump for domestic use that reliably and quietly delivers clean water at a maximum pressure of 5.2 bar?Jet centrifugal pump … a pump with a handle that, as a single-stage centrifugal pump, can be used in a variety of ways for garden irrigation. GUP 46 Clear Water Pressure Pump … a particularly durable pump that operates as a submersible pressure pump underwater in a cistern or tank and is automatically controlled in the house via an automatic switch (pressure switch, e.g., installed in the house). GAP X 80 Automatic Submersible Pressure Pump … an automatic submersible pressure pump designed for the reliable extraction of clear water from rain barrels, rainwater systems, flat tanks, and cisterns for the irrigation of gardens and green spaces. TPV 200 wastewater pump ... a particularly durable, heavy-duty pump capable of pumping wastewater from a tank/cistern, a pit, or a basement.

Regular price: €429.00
Regenfasspumpe GAPX80  Tauchdruckpumpe
Rain barrel pump GAP X80, automatic, with dry-running protection

GAP X80 Rainwater Tank Pump – Your Automatic Submersible Pump with Dry-Run Protection The GreenLife GAP X80 automatic submersible pump is a high-quality, reliable, and powerful device designed specifically for extracting clear water from rain barrels, rainwater systems, flat tanks, and cisterns. The pump can be used, among other things, for emptying rainwater storage tanks as well as for watering gardens and green spaces. The pump is fully submersible and is immersed in the water. Water delivery is automatically controlled when the line to the consumer is opened. When the consumer is closed, the pump switches to standby mode. The pump then enters start/stop mode and maintains pressure in the line. Included as an accessory is a telescopic tube with a bracket (hose kink protection) to position the pump at the edge of the tank. The convenient shut-off valve with quick-connect coupling allows you to easily draw water from the rainwater barrel. If the pump is located in a tank or cistern, a water connection box or garden tap can be operated directly via the ¾-inch connection. Product features and benefits at a glance Integrated dry-run protection & thermal fuse – protects the motor and pump from damage in case of low water level or overload Protection class IP X8 – for continuous operation underwater High flow rate – up to 83 l/min (5,000 l/h) at a maximum head of 20 meters (2.0 bar) Pumped medium: clear water – suitable for clean water, preferably filtered, max. temperature 35 °C Robust construction – fully submersible, housing made of durable plastic Fully ready for connection – includes a 10 m power cord, telescopic tube, shut-off valve, hose holder, quick-connect coupling, and mounting hardware Easy to handle – lightweight at 6.3 kg and with an integrated carrying handle Even easier for you: service & consultation included Expert advice on selection, installation, and combination with connection accessories Free shipping within Germany Guaranteed pickup service within Germany in case of repair during the 24-month statutory warranty period Applications Irrigation of gardens and green spaces – directly from rainwater storage tanks Operation of garden water taps and garden irrigation Can be integrated into automatic irrigation systems for balconies, patios, and home gardens Feed pump for flat tanks and cisterns in residential and commercial settings Notes Do not pump saltwater, wastewater, corrosive, highly flammable, or explosive substances (e.g., gasoline, kerosene, nitro thinner), or oils such as heating oil and vegetable oils! The water temperature must not exceed 35 °C. If there is a risk of frost, drain the pump and store it in a frost-proof location. Please follow the installation and operating instructions. Do you have questions? We’re here to help. Our customer service team is here to assist you with any questions regarding pump selection, installation, or accessories. Phone: 0385 / 77337-0 (7 a.m.–4 p.m.) Technical Support: 0385 / 77337-72 (8 a.m.–4 p.m.) Email: info@greenlife.de

Regular price: €159.00
zisterne zulaufberuhiger
Two-part inlet stabilizer - to improve the water quality

DetailsSmooth inflow of rainwater into the rainwater storage tank. Fine dirt particles slowly settle to the bottom and form a sediment layer, which has been proven to have a positive effect on the stored rainwater. This prevents the sediment layer from being stirred up, while simultaneously supplying oxygen to the stored water.Technical DataMaterial: PolyethyleneHeight: 320 mmDiameter: 260 mmConnection: DN100 (Ø110)

Regular price: €39.95
Entlüftung Wassertank
Air Inlet and Outlet with Emergency Overflow, DN 100

Vent and Drain Valves for Safe Pressure Equalization & Reliable Emergency Drainage The vent and air release valve with DN 100 emergency overflow ensures reliable air equalization in tanks, pipelines, and infiltration systems and effectively protects the system against overpressure or underpressure. If the maximum water level is exceeded—for example, during heavy rain— the component also functions as an emergency overflow to ensure safe drainage. The vent and air release valve is typically installed at the end of an infiltration system and is usually discreetly located outdoors, e.g., in a hedge or flower bed. To ensure that (rain)water can flow smoothly into the system, a controlled air outlet must be ensured elsewhere. To achieve this, a DN 100 KG pipe is installed behind the system, which safely directs the air to the surface. The vent is the terminal point of this line and is designed to reliably prevent animals from entering. Product Features & Benefits at a Glance Pressure equalization during water withdrawal or supply —prevents damage caused by overpressure or underpressure Automatic venting and air intake – ensures trouble-free system operation Integrated emergency overflow – protects against overfilling during heavy rain Standard DN 100 connection – compatible with common KG pipe systems Lightweight & durable – approx. 350 g, made of robust polypropylene Made in Germany – manufactured to high quality standards and DIN EN ISO 14001:2015 Typical Applications Rainwater storage tanks & infiltration systems – for ventilation and emergency drainage Wastewater collection pits & infiltration systems at wastewater treatment plants – for pressure equalization and operational reliability Sustainability The product is made of durable, single-grade, and fully recyclable polypropylene. The material is long-lasting, environmentally friendly, and chemically inert—it has no impact on the environment. The production and recycling of this plastic are carried out in a resource-efficient manner. Responsible use in line with the circular economy is, for us, a central component of sustainable action. Notes The vent should be inspected once or twice a year to ensure consistently reliable operation.

Regular price: €45.00
kleintierschutz siphon
Overflow siphon with skimmer effect and animal protection

DetailsDN100 overflow siphonmounted on the inside of the vertical tank wallOdor trap to the storm sewerCleaning of the water surface via skimmer effectSmall animal protection—to prevent rodents from entering

Regular price: €69.00