What is Rainwater Harvesting?

It is simply a method of collecting rainwater from a buildings’ roof (via the normal drainage system), filtering and storing it for re-use, in order to reduce the amount of water used from the mains supply, and to reduce the amount of stormwater run-off.

It is important to understand the difference between the options when choosing a system for harvesting rainwater for your project.

With water prices rising and the continually increasing demand for water consumption, more and more businesses are realising the benefits of harvesting rainwater. There is also a growing desire and consumer demand for companies to operate more sustainably and to reduce their impact upon our environment.

Rainwater harvesting offers not only a solution to reducing demands on water supplies, but can also give significant financial benefits, in some cases saving £1000’s year on year. With many new commercial buildings being constructed to meet the requirements of BREEAM, rainwater harvesting is becoming increasingly commonplace and is now a well tried and tested technology.

Rainwater harvesting systems for commercial and industrial buildings are generally bigger, more sophisticated versions of those used for domestic situations.

Commercial Rainwater harvesting. System for harvesting rainwater

Most components will be larger, in particular tanks and filter units, and sized to suit the supply and demand of water required. Commercial installations will often involve additional features for ease of control and to ensure uninterrupted supply, and can include features such as UV disinfection, automatic backwashing, or monitoring display units.

Rainwater harvesting commerical system
Many commercial buildings are suitable for harvesting rainwater

Harvested water can be put to many commercial uses and buildings with a high demand for non-potable water can see immediate savings benefits, giving a quick return on investment. With a wide range of products on-hand and our considerable expertise in harvesting rainwater, we can supply solutions to meet all requirements.

Schools are particularly suitable due to large roof areas and high number of occupants.
About your needs

With any commercial system, it is important that we gather as much information as possible about the building and its use, as this will allow us to provide you with the most appropriate solution for your need.

The location, size and structure of the building, as well as detailed information about the potential demand on the rainwater supply, are all crucial to choosing the design and scale of the system to be installed.

For example, a building with 500m2 of roof area will require a much smaller tank than a building of twice that size as the size of the roof is proportional to the amount of rainwater harvested.

Similarly, an office accommodating 100 people will use a lot more water than one with only a handful of people working in it. The nature of your business could also have a bearing on the size and complexity of the chosen system.

Whatever your requirements we can provide a bespoke solution to suit your needs. Simply tell us as much as you can about your building and how you use it and we will do the rest.

System Types

It is important to understand the difference between the options when choosing a system for your project.

Direct System

A ‘direct’ system, as its name suggests, collects and sends water directly to the points of use. It includes a backup connection from the mains cold water supply fed into the harvesting tank. The tank will receive a partial low-level refill from the mains supply as and when required. The important thing to bear in mind here is that the supply of water is dependent upon the electric pumps, so if there should be a power failure, it will not be possible to use the appliances connected to the system.

raintech direct system
Indirect System (Gravity or Boosted)
diagram commercial rainwater harvesting

An indirect system differs in that it includes a second (invariably smaller) tank located within the building. This acts as a break tank which accepts the backup connection from the mains water supply. If used at high level as a header tank (indirect gravity system), then even when there is no power available for the pumps, the system will continue to run uninterrupted.

The outlet from this tank can be boosted if a greater pressure is required, or if it cannot be located sufficiently high enough within the building for gravity use. A booster set can consist of one or more pumps and will be sized according to requirements (boosted gravity system)