Rainwater for your toilets, washing machine and garden
The Carat Direct system collects the rain that falls on your roof and stores it underground, then pumps it to your toilets, washing machine and outside tap. It can also be used for garden watering and outdoor cleaning. It’s a complete package for homeowners, self-builders and installers: tank, filter, pump and mains back-up, chosen to work together.
How it works
Rain runs from your downpipes into one pipe and into the tank. On the way in, it passes through a filter that keeps leaves and debris out. A pressure-sensitive submersible pump sits in the tank and draws water through a floating intake.
This is a direct supply system: the pump sends rainwater straight to your toilets, washing machine and outside tap when they need it, rather than filling a header tank in the loft first. When you flush a toilet or open a tap, the pump starts and supplies water under pressure; when the tap closes, the system re-pressurises and the pump switches off. The pump restarts automatically and has dry-run protection.
Mains back-up for dry spells
In a long dry spell the tank can run low. The mains back-up (Mains-on-Tap) unit, fitted inside your home, then tops up the underground tank with mains water so your toilets and washing machine keep working. A float sensor in the tank tells the unit when to do this. It adds only the mains water needed to keep the toilets and washing machine supplied, leaving as much room as possible in the tank for the next rainfall. The unit is quiet and small enough to fit in a kitchen or utility cupboard.
See what happens when the tank runs low: What happens during periods of no rainfall? (video)
Choose your size
The Carat tank is made from 100% recycled plastic and is installed with gravel backfill rather than concrete, which makes installation simpler and saves around £60 per cubic metre. It’s a product from a European market leader.
| Capacity | Length | Width | Total height (with Maxi dome) | Weight |
|---|---|---|---|---|
| 2,700 litres | 2,080mm | 1,565mm | 2,010mm | 120kg |
| 3,750 litres | 2,280mm | 1,755mm | 2,200mm | 150kg |
| 4,800 litres | 2,280mm | 1,985mm | 2,430mm | 185kg |
| 6,500 litres | 2,390mm | 2,190mm | 2,710mm | 220kg |
All sizes have an 800mm tank dome. Choose a pedestrian lid for lawns and garden areas, or a vehicle lid if the tank will go under a driveway.
Useful links
- Want a shallower dig, or a 1,500 or 7,500 litre tank? See the Platin Direct system (1,500–7,500 litres)
- Prefer a header tank in the loft? See the Carat In-Direct system
- Only need water for the garden? See the Carat Garden Comfort system
- Add a Digital Level Indicator to see how much water is in the tank
- Tank going in deeper? Add an Extension Piece
- What can rainwater supply in your home? Read our guide: What does a rainwater harvesting system supply in your home?
- Not sure which system you need? Comparing rainwater harvesting systems: direct, indirect and garden-only
- Work out the right tank size with our rainwater harvesting tank size calculator
Images are for illustration; components may be upgraded or replaced with equivalent alternatives.
