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Rainwater Harvesting

  1. What is Rainwater Harvesting?
  2. How does it work?
  3. Benefits of rainwater harvesting
  4. Grants Available
  5. Rainwater Harvesting Frequently Asked Questions



Sol2o offer consultation, design, installation and maintainance of Rainwater Harvesting systems.

For a Rain Water Harvesting evaluation or a complete energy performance assessment of your property call us now on 0800 2800 020,  or click here to register with us.

What is Rainwater Harvesting?

Harvesting rainwater is one of the oldest and most essential of ways in which we can live sustainably with nature. The value of water is becoming more recognised, as it becomes an increasingly precious resource. With the introduction of mains water supply, harvesting methods in the developed word have been largely reduced. In most buildings naturally clean water rainwater is left to wash away while expensive purified water is used for all applications with only a fraction being used for potable use. More recently, water demand has started to exceed supply, and localised flooding has become an issue. Industry experts are now recognising the important role that rainwater harvesting has to play in alleviating both these problems. By designing and installing rainwater harvesting systems Sol2o can bring intelligent sustainability to all modern buildings.

Global warming has also had an impact on the level of rainfall, which has gradually increased over the past few decades. This has highlighted the problem of storm water entering waterways. Flash floods along with rising sea levels have been responsible for some severe flooding in the UK in recent years. Typically installing a rainwater harvesting system can satisfy approximately 50% of the demand in a typical residential home. Currently the average water use is 150 litres per person per day. By 2016 and the introduction of the code for sustainable homes a form of rainwater harvesting will have to be adopted in the construction of new sustainable homes. New homes need to adopt water efficient devices such as limited depth baths and shallow cisterns. These devices invariably compromise user comfort for the sake of water efficiency. An integrated rainwater harvesting system reduces the need for compromises and reliance on such water efficient devices.

How does it work?

Rainwater harvesting simply collects the rain, which fall onto roofs, once filtered the water is stored for use in non potable applications such as toilets, outside taps and washing machines, thus displacing what would otherwise be a demand for mains-water. Rainwater is stored in large tanks that are usually buried underground but above ground tanks can also be used.

The rainwater that falls onto building's roofs is channelled through the standard guttering and pipework, Rather than going through the drain it passes through a mesh filter (to remove leaves and debris) before entering a storage tank, which are usually buried underground. When needed the water is automatically pumped back into the building and after filtration is put to use in non potable applications such as toilet flushing, outside taps, laundry and commercial washdown areas. Float level switches within the tank to alert an electronic control device to divert to mains supply should the storage tank run empty. However the system will always draw on harvested water first.

Benefits of rainwater harvesting

  • Rainwater harvesting displaces a large proportion of the water that would otherwise be provided by the mains supply - thus reducing overall water supply costs.
  • It can provide an off-mains supply for remote areas.
  • It enhances a property and can completely satisfy the water requirements of the various levels of the code for sustainable homes.

Grants Available

There are no grants available for domestic installations yet, although several organisations are petitioning the government for assistance. For commercial installations, there is a tax relief scheme (ECA) for suitable approved equipment on technology list.

Rainwater Harvesting Frequently Asked Questions

Is rainwater harvesting suitable for work as well as at home?

Yes, in schools, hospitals, offices, commercial premises, rainwater can typically be used for toilets, vehicle washing, yard washdown and watering plant pots/gardens.

How much water can a system save?

Depending on your normal usage, it can save 30 to 50% of the treated drinking water from the mains in houses and up to and up to 80% of the treated drinking water in a business or commercial building.

How much would this save on water bills?

Depending on your normal usage, it can save 30 to 50% for the domestic user and 80% for the commercial user of the treated drinking water from the mains. Having metered water is the best way of appreciating the difference.

How much rainwater does a system collect?

This depends on the area and angle of your roof, and your rainfall. Averages of 100,000 litres per household are commonly quoted, much more for large roofed commercial buildings.

What can you use the water for?

Filtered, untreated rainwater should only be used for non- drinking or bathing purposes: toilet flushing, gardens and vehicle or yard washdowns.

Where is it installed?

The tank should be buried under a car or vehicle park, landscaped area, garden, patio or drive, with space left for the round access cover. Most systems are designed so that they can accept cars driving over them if suitably installed.

How clean is the water?

The rainwater is filtered as it enters the storage tank, to remove particles and other matter. It is kept in the dark and kept oxygenated to discourage algal growth, and properly designed systems are designed with calming inlets, which ensure that any sediment at the bottom of the tank does not get stirred up. The water is not drinking water fit for humans.

Could rainwater get into my drinking supply?

Not in a properly designed system, the pipework is entirely separate and should be identified as non-potable.

How is the system maintained?

The internal filter should be washed about once a quarter, otherwise maintenance is not needed. The only moving components - pump and float switch have an extremely long life. The system should be designed to overflow a few times a year, to remove floating matter.

0800 2800 020



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Rainwater Harvesting

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Rainwater Harvesting