Installer Directory


Janet Richardson


Updated on

Aug 06, 2023

Read Time : 3 Minutes

Are Rainwater Harvesting Systems Worth It?

Whilst we all know our resources are limited, it’s only when there is a drought that we realise what a valuable commodity water is. After all, we simply turn on the tap and out it come: clean, fresh water. For most consumers, the question of whether a rainwater harvesting system is worth the cost is a twofold issue:

  • There’s the need to conserve our resources and cut down on waste, and
  • There’s the return on investment that we might receive in reductions on our water bills by installing a rainwater harvesting system.

Though the UK is blessed with many reservoirs that supply our daily needs, we are not as rich in water as most of us would like to believe. It’s true that other European countries have over twice as much per capita head as we do, despite our reputedly dreary weather.

On average we use around 150 litres a day and the research suggests that by the year 2030 our growing population will mean that demand is going to outgrow supply by as much as 40%. Of course, we don’t all need to start rushing out to buy a rainwater harvesting system but there are several things we can do to cut down on our consumption.

Introducing something like a toilet ‘hippo’ into your cistern (essentially a container filled with water that reduces the space) can cut down on how much we use with each flush. Turning off the tap when we clean our teeth rather than leaving it running and other minor measures can all reduce our water usage.

The Cost vs the Benefit of Rainwater Harvesting

Rainwater harvesting is unusual in renewable technologies in that there is a system to suit most pockets. Something simple like a water butt for the garden can cost between £70 and £80 and recoup its cost over a period of 18 months when set up properly and used to water the garden.

A top of the range rainwater harvesting kit can cost between £2,000 and £3,000 and will take longer to gain a return on investment, perhaps in the region of 15 years, for an average domestic household with a water bill of £5-600 per annum. If you are getting someone to professionally install your system and are having it placed below ground, then you could be looking at almost doubling the cost of installation and lengthening the time that you see that return on investment. That, of course, does not take into account the possibility of water bills rising in the future if demand starts to far outstrip supply.

Where rainwater harvesting begins to create a more impressive return on investment is in the commercial arena, primarily because the water usage is higher. For businesses who have the space and can install a large tank, the cost far outweighs the benefits with the initial investment being paid off within a few years. If water usage is large, for instance in a busy hotel, that payback can happen even quicker.

  • Large roof spaces allow more water to be collected, which means you can opt for a bigger storage tank.
  • For a number of commercial premises the use of rain harvested water for things like flushing toilets can mean a considerable reduction in the amount that is paid for your mains supply.


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Government Encouragement for Rainwater Harvesting Systems

As we realise the need to conserve one of our most valuable resources, a number of initiatives have been introduced to encourage the construction industry to bring in rainwater harvesting measures when they start a new build. This is particularly true for commercial premises where the use of renewable technologies is a priority.

Innovations such as the Code for Sustainable Homes and the Enhanced Capital Allowance Scheme make it more profitable to install a rainwater harvesting system.

The Future of Rainwater Harvesting

The truth is that we may well not have a choice when it comes to rainwater harvesting, particularly on a larger, commercial level. With demand rising and supply lagging behind, businesses have been slow to take up the lead in this particular arena of renewable technologies.

Where energy production is concerned, we can find a variety of different ways to produce the power we need that is both environmentally friendly and economically viable. It’s a different matter for water – we need our reservoirs to fill up before we can access it. The problem, according to the Carbon Trust, is that many business bosses currently believe that installing something like rainwater harvesting would cause a decrease in company profits. They highlight the supermarket chain Sainsbury’s as one of the leading lights in economising on water usage, installing low flush toilets and rainwater harvesting systems to reduce their dependence on the mains supply.

Whilst businesses with the space can achieve a return on investment quite quickly after installing a rainwater harvesting system, it’s a little more difficult with domestic properties who want to see a profit. Homeowners may well be reluctant to take up the technology because of the initial cost and the much longer period of payback. New builds may well, in the future, have it installed as a matter of course, but retrofitting existing properties could be expensive and unfeasible without some government encouragement. Find out more about the different types of rainwater harvesting here

In conclusion

Rainwater harvesting systems prove to be a valuable and sustainable solution for water conservation. Their numerous benefits, ranging from reducing water bills and lessening the strain on municipal resources to mitigating flood risks and enhancing local biodiversity, make them a worthwhile investment. By harnessing nature's gift of rainwater, individuals, communities, and businesses can actively contribute to a greener and more resilient future.

Although initial setup costs may be a concern, the long-term economic and environmental gains make rainwater harvesting systems undeniably worth it. Embracing these eco-friendly practices can lead us towards a water-secure and environmentally conscious world for generations to come.

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