How to  recover rainwater?

How to recover rainwater?

Albert, Manager of a gardening service, Leicester

Guide written by:

Albert, Manager of a gardening service, Leicester

49 guides

Collecting rainwater to water the garden and accomplish other tasks can save a lot of water. Here are all our tips for the most efficient and eco-friendly configuration, from the underground tank, equipped with surface pump to the 500L rainwater butt placed at the end of the roof's slope.

Important features

  • Surface tank
  • Underground tank
  • Rainwater butt
  • Installation
  • Legislation
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An eco-friendly solution that saves you money

It is well known fact: fresh water is a precious commodity which, unfortunately, is becoming rarer by the second. Any additional knowledge or tips about how to bestconserve this vital resource is always good to have. Recovering rainwater would be one general tip,  but that's only the start! The theory is simple: whenever it rains, the water that comes down your roof is captured and stored in one or more tanks referred to as butts.

Different uses, legal framework and implementation

Before starting the process of purchasing a rainwater recoverer, the collected water's intended use must be determined. Next, remember to consult any relevant legislation in this area. Finally, using the criteria that was previously determined, we can proceed to the selection of the most suitable device.


Uses for rainwater and legal framework

Rainwater presents several advantagesforoutdoor use. First, from a legal point of view, its use outdoors is unlimited. The rainwater normally contains very little lime, no minerals and its PH is low enough to be considered slightly acidic. These characteristics makes the water of very good quality and perfectly suited for watering ornamental plants or a vegetable garden. Recovered rainwater can also potentially be used for washing the car. In both cases, having saved a significant amount of drinking water is the most important feature!
Rainwater may also be used inside the house, provided that a number of guidelines are met. Here are a few of these guidelines to get started.
First, it should never be intended for food consumption as the water is not safe to drink. 
Furthermore, a secondary network must be installed with specific taps for each source. These taps must not coexist, even in the same room, with the exception of garages, cellars or auxiliary rooms. Even with the exceptions however, they must be able to be completely blocked with an external tool and can not remain permanently accessible. Finally, any rainwater tap must have special signs, including on any toilets that are connected to the network. Rainwater can also be used for washing clothes, if equipped with a suitable filtering system.

It's important to remember that a formaldeclaration must be made in town hall before any indoor installation can start and that a specific set of conditions must be respected in terms of network, tank, filter and general maintenance. The number of cubic meters used on the sewage network as a whole must also be calculated and declared. There are also special circumstances and limitations. For example, in case of presence of asbestos-cement or lead in the roof's materials, the use of any rainwater recovered from it will not be permitted for domestic use. Whatever configuration you end up going with, it is crucial that you be well informed before embarking on an indoor installation.

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Vegetable garden

Installation process

There are several different water recovery devices available. All of them follow the same mode of operation. Starting from the roof, here are the main components:

  • Hanging underneath, all around the roof, the gutters recover the water coming down from the roof;
  • They are equipped with some sort of sheet filtering system, either a downpipe filter or a gutter filter, also referred to as a gutter guard, or ideally both;
  • Other gutter accessories can provide additional filtering or contribute to strength and tightness of the assembly;
  • The downspout, which links the gutter system with the city rainwater network, will then normally carry on with the evacuation of rain water.


It is at this moment that the rainwater collector intervenes, as it is connected directly to the downspout. Here are the essential components of its installation, which represents the starting point for any rainwater storage solution:

  • The rainwater collector;
  • The rainwater butt.

There are various types of both rainwater collectors and butts. Collectors are available in the form of pre-fabricated kits or directly integrated in the downspout, neither of which require any cutting. The butts themselves have various shapes, with more or less aesthetic features and different storage capacities.

To ensure proper installation, it is essential to install the rainwater collector on a flat and stable surface
If the floor slopes even the slightest bit, a perfectly horizontal concrete slab will be needed as a support. It must be completely straight (to check with a level) and wide enough to support the weight. After connecting the collector to the downspout, it must be linked to the butt. 
Some models are equipped with an overflowsystem, which allows for the routing of any excess water to the rainwater network once the tank is fulll, without any intervention from the user.

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Water recovery with underground tank


This configuration is intended for optimal use of rainwater inside the house. It generally has a large storage capacity of up to 5,000 liters. 
Its installation is complex, requiring an important amount of work. It must also be paired with a surface pump to ensure the constant flow of water from the tank to the home's secondary water network and outward. 
An overflow device connected to the run-off water collection system must be installed as well as an additional tank filtering system.

Although it requires an important investment, a rainwater recovery system can achieve very significant savings, both in the medium and long term. This is all contingent, of course, on the installation being in a region that receives sufficientrainfall to justify such an investment and the scrupulous compliance with any and all legal and regulatory provisions dictating the use of domestic rainwater.

More information

Big, medium or small, any home can benefit for saving water. Follow the links below for other ideas, related accessories, advice from our editors and more helpful guides on how to best accomplish your water conservation goals:

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Guide written by:

Albert, Manager of a gardening service, Leicester, 49 guides

Albert, Manager of a gardening service, Leicester

For several years I have been running a garden service with a clientele of both individuals and companies. I manage a team of gardeners and ensure the creation and maintenance of green spaces. At the same time, I bring my expertise to my clients in terms of the maintenance and improvement of their gardens. In fact, as a trainee and working in the hospitality industry at the beginning of my career, I focused on landscaping in a local community where I acquired solid technical skills through in-house training and the follow-up of major projects in a rapidly changing town. On a personal level, I am equally oriented towards the art of gardening. With my wife, I created our garden from start to finish and I maintain it carefully, the same goes for the vegetable garden. As for DIYing, it’s not to be outdone. Yes, gardening is also tinkering: pergola, hut, pavement, fence, and so on...There is always something to do in a garden. After working well together, my wife and I are proud of the result and delighted to be able to take full advantage of a friendly and warm environment. So, let us give you advice and help you in your choice of tools, maintenance, or improvement of your garden, nothing could be simpler.

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