Rainwater harvesting Systems


Our rainwater harvesting systems work by using the rainwater that has fallen on a rooftop. The rainwater is then piped, filtered, and stored in an above or below ground water storage tank(s).

When needed, the rainwater is then pumped directly to the point(s) of use (direct pressure system/suction system) or to the point of use via a header tank (gravity fed system).​

Our systems are for non-potable use. In most cases, they are used to supply toilets, washing machines, and outdoor taps (for garden use).


Gravity Fed Systems

How do they work?

This system (also known as an indirect pressure system) works by pumping the rainwater from the storage tank with the submersible pump to the point(s) of use via the header tank.

When demand is placed on a point(s) of use, such as a WC being flushed, water is gravity fed from the header tank to the point(s) of use.

Our header tanks have a mechanical delay action; this means that a WC or similar demand can be flushed several times before the pump starts and fills the header tank completely in one go.

What happens when there is no rain?

Should the underground tank become low, the header tank will continue to be depleted until the level has reached the mains water top-up level.

At this point, mains water is introduced directly to the header tank and used instead of rainwater until there is sufficient rainwater in the storage tank again.

Once the storage tank has sufficient rainwater, the submersible pump will automatically engage and pump rainwater back into the header tank. At that point, the header tank controls will switch the system back to rainwater use.

This means that none of the points of use will ever be without a water supply.

Gravity-Fed System Benefits

As the pump is starting and stopping less frequently than direct pressure and suction systems, power consumption is considerably less, and pump life is longer.


Direct Pressure Systems

How do they work?

This system works by supplying the water directly to the point of use.

For example, if a toilet is flushed, then straight away the pump is automatically engaged and water is pumped to refill the cistern.

The pump stops when the pressure in the rainwater harvesting pipe-work has been restored.

This means that none of the points of use will ever be without a water supply.

What happens if there is no rain?

Should the storage tank reach a low-level of rainwater, then the mains water top-up control is engaged.

At this point, mains water is introduced directly into the storage tank, but only the minimum required. Thus, leaving the maximum capacity to receive the next rainfall.

Once the storage tank has a sufficient level of rainwater the mains water top-up control is disengaged and rainwater is again, pumped to the point(s) of use.

The controls come complete with a class AA air-gap required for water regulations.

Direct Pressure System Benefits

The system is ideal if you don’t have an attic/loft space to install a header tank (used for a gravity-fed-system).


Suction Systems

How do they work?

This system, as with the direct pressure system, works by supplying the water directly to the point of use.

For example, if a WC is flushed, then straight away the pump is automatically engaged and water is pumped to refill the cistern.

The pump stops when the pressure in the rainwater harvesting pipe-work has been restored.

The main difference between the suction system and direct pressure system is the pump is located in the building (not in the storage tank) and, as the title suggests, rainwater is suctioned from the storage tank to the point(s) of use.

What happens if there is no rain?

If there has not been any rainfall and the storage tank reaches a low-level, then the mains water top-up control is engaged.

At this point, mains water fills a holding tank (with air-gap) inside the suction control console. Mains water is then pumped to the point(s) of use by the pump, also located inside the control console.

Mains water is used until the rainwater harvesting system detects sufficient rainwater in the storage tank. At this point, the controls switch the system back to rainwater use.

This means that all of the points of use will have a continuous water supply, either rainwater or mains water.

Suction System Benefits

The benefits of the system are that the pump and controls are all neatly located inside the system console which is installed inside the building. It is also ideal if you don’t have an attic/loft space to install a header tank (used for a gravity-fed-system).


Garden Systems

How do they work?

This system, as the title would suggest is for your garden. It works much like the direct pressure system, by supplying water directly to the point(s) of use.

For example, when the garden tap is turned on the pump is activated giving you the water pressure needed. When the tap is turned off the pump is deactivated.


Bespoke Systems

Custom made rainwater harvesting systems are available, whether you need an above-ground or underground storage tank. A system capable of supplying enough rainwater to wash a fleet of buses, or you need a system suitable for watering plants on a rooftop garden.

We can design and build commercial or domestic rainwater harvesting systems to your exact requirements.

We also service and maintain commercial and domestic rainwater harvesting systems.

Please send us your specifications for a competitive quote.

Contact us for further information and expert advice!

Commercial Rainwater Harvesting