As our fears about climate continue to grow, sustainability has become one of the most important words in all our lives. Rainwater harvesting offers an eco-friendly way of reducing the amount of water we use, which could be critical in years to come. Here we explain why rainwater harvesting is important and how it could help combat a growing water crisis in the UK.

How can rainwater harvesting save water

Water conservation has become an increasingly important topic in recent years as the need to address climate change is more urgent than ever before.

Groundwater is one of the primary sources of freshwater that is used for domestic, agricultural and industrial purposes. But it is now widely recognised that the ongoing exploitation of groundwater resources for everyday usage is creating a large amount of water wastage. Technology is doing what it can to limit water wastage, but the onus also falls onto individuals to be more efficient with their water usage.  

This is where rainwater harvesting comes in, offering a solution that allows rainwater to be stored for future use. There are a variety of affordable domestic systems available, from overground units to larger underground storage tanks – some models combine stormwater and rainwater processes, while others turn H2O into potable (drinkable) water.

With fluctuating climate conditions and depleting groundwater levels, rainwater harvesting can help to reduce the effects of rising water scarcity. Local aquifers will have more time to recharge, localised flooding can be reduced and there will more water available in areas where levels are starting to lower.  

Rainwater harvesting legal requirements

The good news is that harvest rainwater is not regulated by the Environmental Agency if it does not harm the environment.

An abstraction licence is not required to use harvested rainwater, although if it is combined with surface or ground water, this may be needed. You probably won’t need to seek planning permission for installing a harvesting system as it is usually covered by ‘permitted development’ rights, although you should always check with the local authority just in case. 

The pending UK water crisis

As part of the Public Accounts Committee’s (PAC) inquiry in the UK’s water sector and infrastructure, it was found that about one-fifth of the volume of water used in the UK every day is lost to leakage. This has been the case for more than 20 years, and while Ofwat (Water Services Regulation Authority) predict that leakage will be reduced by 16% by 2025, the PAC are not confident the appropriate level of action is being taken to reach this target.

The committee also believe that if the issue remains unresolved, as the population grows, urbanisation continues and the climate warms in the UK over the next couple of decades, England could face large water shortages. Unless these issues are resolved as a matter of priority, by 2050 the UK may have to deal with the reality of not having enough clean, drinkable water available on tap.

Concerns have also been expressed that the water sector’s lack of action regarding their 2030 net-zero target will also have severe consequences. New energy-intensive infrastructure required for modernisation will have to be built and there is no clear plan on how to deal with the associated emissions.

The Environmental Agency estimate that there will be a 15% decrease in summer rainfall by the 2050s in England, with some rivers seeing 50-80% less water during the summer months. By the year 2100, they predict that temperatures between 35°C and 40°C could become the norm.

Avoiding the ‘jaws of death’

While there is still time to avert a water shortage in the UK, these are dangers that need to be quickly addressed by water companies to avoid what is referred to by industry experts as the ‘jaws of death’. This is the point where there is not enough good quality water available to supply our needs, unless action is taken.

Demand could be lowered by reducing leakage, increasing water metering and building more sustainable drainage systems. New building regulations should be introduced to encourage greater water efficiency, and individual usage must also be reduced.

Supply can be increased using a variety of methods. This includes the transferring of more water between regions from areas of surplus to areas of deficit (only around 4-5% is currently transferred). A larger number of desalination plants need to be built to provide more water, while new reservoirs can also help, although it has been some decades since the last one was built.  

What are the benefits of rainwater harvesting?

The benefits of increased rainwater harvesting include:

Lower water bills

If you live on a metred property, rainwater harvesting can reduce your water bills as less water will come out of your taps. From washing the toilet and cleaning the car, to watering the garden and dowsing the driveway, rainwater can be put to a lot of different uses.

Eco-friendly

Local drainage systems benefit from rainwater harvesting because rainwater is diverted into storage tanks rather than heading directly down into the drainage network. Also, land is not used for water storage purposes which means people are not displaced, ensuring groundwater isn’t exposed to evaporation and pollution.

Reduced groundwater demand

Aquifer productivity increases as a result of rainwater harvesting, which allows groundwater levels to rise, which in turn, lowers the need for potable water. For areas with low water levels, this is a very important point.

Improve irrigation

The collection of rainwater also leads to better irrigation, which is a leading cause of depleting groundwater levels. Rooftops are designed with water filtration in mind and connecting these to harvesting systems is a straightforward process. Rainwater is mostly free from harmful chemicals which makes it ideal for irrigation.

Reduced ground erosion

Soil erosion becomes an issue when flooding occurs, weakening the infrastructure of buildings and causing a litany of other issues that can be costly to repair. As already mentioned, rainwater harvesting helps to reduce the risk of localised flooding, helping the environment and nearby properties – domestic, commercial and industrial. This also applies to stream banks, as by reducing stormwater runoff, the velocity and peak flow in local rivers, streams and creeks can be reduced.