What is Rainwater Harvesting?

In this article the water reuse experts at Water Treatment Services explain what rainwater harvesting is, how it works and the benefits to be gained from its implementation.

The article highlights the benefits of harvesting rainwater for property owners, residential and commercial users, and the environment; what the water can be used for, and considers some of the challenges faced when implementing such water reuse systems.

Environmentally friendly water reuse

You may have come across the environmentally friendly process called rainwater harvesting before, but how much do you really know about it, how does it work… and how do you do it?

Rainwater harvesting can be done on a small domestic or large commercial scale, depending on your preference and ability to implement it. This article goes into depth about what it is and the various aspects of water harvesting you should think about before diving in.

What is rainwater harvesting and how does it work?

Rainwater harvesting describes the collection, storage and reuse of rainwater that would otherwise be lost to the drainage system. Rainwater is typically collected from building roofs, and then re-used for irrigation, flushing toilets, in washing machines and similar applications. Harvesting rainwater can improve environmental sustainability and reduce water bills making it a great win-win solution for businesses and home owners alike.

The term refers to the collection of rainwater that falls on your property, and while this may make you think of a water butt connected to a downpipe, and we’ll cover that shortly, this is the most basic example of a harvesting system. However, there are far more advanced methods available that can help you collect thousands of litres of rainwater to use for various purposes.

Is collecting rainwater illegal in the UK?

Firstly, the good news… it’s not illegal to harvest rainwater in the UK. However, there are laws in some American states that prohibit this, but thankfully this isn’t the case in the UK. Secondly, you are freely able to collect all rainwater that falls within your property boundary. You just need to work out the best way of doing it and then treating the water so it’s fit for purpose.

What are the benefits of rainwater harvesting?

The biggest benefit is that the water can be used for all manner of things rather than going to waste down the drains. The most obvious use is in the garden, but it can also be used to flush toilets, for washing machines and other non-potable water activities, depending on the type of treatment processes you have in place. Using a hosepipe to water your lawn and plants means you’ll get through around 15 litres of water every minute. If you are on a water meter, this will soon mount up and push up your bills too.

Simply installing one or more water butts means you can collect rainwater and use that instead during dry periods. One water butt will likely run dry during a prolonged dry period, but if you have the space, it’s easy enough to install a series of water butts to collect the largest amount of rainwater possible.

However, this is only the beginning of rainwater harvesting. It’s akin to dipping your toes into the water if you will. A proper harvesting system will involve a tank, usually installed underground or nearby, a pump to take the water inside the building, a filter, a water treatment system and a rainwater harvesting pipe. The harvesting system is designed to collect rainwater from the roof of your property – it should not be taken from hard standing areas or the ground. If this were to occur, it will then have waste products in it that prevent it from being safe to use in some circumstances.

Water harvesting can help reduce your water bills by as much as 50%

Obviously, how much you can save will depend on your property and the size of the water storage tank used, along with how responsible you are with water use. However, if you are currently on a water meter, as most businesses are, you will notice a substantial difference.

The savings made for reusing the water in your garden will depend on how often you water your garden now. The more important it is for you to have a lush green lawn, the more money you can save by using a rainwater harvesting system.

However, you can also use collected rainwater to flush toilets and run washing machines. Flushing toilets is estimated to account for around 30% of the total amount of water used in the average property. Since rainwater harvesting can be used for this purpose, it’s clear there are significant savings to be made.

Harvesting rainwater will also reduce surface water runoff

Surface water is water that does not go down the drains or is otherwise collected in a water butt or storage tank, as we have seen with rainwater harvesting. It’s water that sits on a surface that cannot soak it up.

So, if rain falls onto the lawn or flowerbeds, it’ll soak in (unless there has been a prolonged dry period with warm weather that has led to the ground being baked dry and cracked). If the rain falls onto a patio, it cannot go anywhere unless the patio has an angled fall to it that will allow for runoff into the flower beds or to drains.

If it rains heavily, this can cause flooding, which in turn can cause damage to properties. You can see that rainwater harvesting therefore reduces the degree of surface water that may occur on an individual property. With far less water going down the drains, instead being funnelled toward the water storage tank for reuse, surface water runoff becomes far less of an issue to worry about.

The mains water supply acts as a backup

Should the tank collecting the rainwater run low, the existing mains water system takes over, allowing an amount of water to enter the tank to prevent it running dry. A rainwater harvesting system is designed to cater for each specific property too, so there is less chance of this happening to start with.

Once installed, the only noticeable difference is a much lower water bill, as the harvested rainwater takes over from mains water for specific uses. And with toilet flushing accounting for a third of our water use, you can see how a rainwater harvesting system can pay for itself reasonably quickly.

Ongoing maintenance and water treatment is necessary to maintain the life of the equipment, the quality of the water and safety of people using it. As for controls, mechanical ones are more energy efficient, by-passing the need for electronics that require electricity to run.

Is rainwater harvesting the future for water reuse?

With several methods available for harvesting rainwater, including everything from the humble water butt to larger, commercial in-ground water storage, it’s clear that finding the best way for you to harvest rainwater is the starting point.

Some systems are more expensive than others, yet they allow the collection of greater amounts of water. Much depends on budget and on space, as well as the practicality of potentially digging a hole big enough to store a tank underground.

However, the environmental benefits are obvious, and the savings are considerable with the right system. With significant savings to be made on water bills, perhaps it is time we all considered rainwater harvesting.

Expert environmental and water reuse solutions

Water Treatment Services offer a comprehensive range of innovative environmental and water reuse solutions for business. Our experts can provide advice and support to help you identify the most appropriate strategies for the implementation of environmentally sensitive rainwater capture, testing, monitoring and treatment solutions for water reuse projects.

With offices in London serving the South and South East England, Manchester (North West), Birmingham (Midlands), Bristol (South East England and Wales), Leeds (North and North East) and Glasgow (Scotland), supported by regional teams of specially trained environmental engineers and water treatment specialists we offer cost effective environmental support solutions across the whole of the UK and internationally.

Contact us today to learn how our rainwater harvesting and environmentally friendly reuse solutions can help you optimise your use of water resources to lower costs and improve environmental performance.