Rainman Rainwater Harvesting System

Shay Murtagh Ltd are in business for over thirty years and have worked in the water industry for that length of time. We provide storage solutions to local authority and group water schemes nationwide.

We realised that storage and filtration was only a temporary measure to achieve high quality water services in Ireland. With a growing population creating high demand on existing plants, water quality declined in some areas.

After extensive research the company launched Rainman in 2004. Rainman is a high quality product that delivers on an alternative water source for recycling in any market sector which is at a reasonable cost and is low in maintenance.


Manufactured in a range of sizes under stringent quality process, precast concrete tanks offer a corrosion free, durable and robust advantage


Precast Concrete Tanks require no additional ground works such as base preparation and a surround of readymix concrete. As a result, on site work and material costs are dramatically reduced.


We work together with contractors to supply their requirements in an efficient and cost effective approach. We look at each project individually and quote directly for tankage only or complete packages as required by the client.

Rainwater Harvesting Applications

Public Sector

Rainwater Harvesting System for Domestic use

We use water every day for bathing, cooking, cleaning and most importantly drinking. Figures show that in general the amount of water used by any one person is approximately 150 litres.For the majority of households this is potable water / drinking water.

However, we do not need drinking water to flush our toilets, wash clothes or water the garden, there is an alternative source.

Rainwater is an alternative source

Before all houses had piped water we used rainwater for all other functions except drinking and now we are going back to this technology to reduce the quantity of drinking water we take into our households. There is a cost of taking raw water to potable water. Energy and chemicals are used to give us drinking water which has to be financed. However using this same water for flushing toilets is wastage.

Rainman Rainwater Harvesting System – General Domestic System comprises of

  • 1 no 9 cubic metre precast concrete tank complete with lid and access manhole.
  • 1 no Volume Filter
  • 1 no. Calmed Inlet
  • 1 no. Overflow Siphon
  • 1 no. Ball Float, Pump and Mains Top Up

It is installed by our qualified installation team who are available at all times to discuss any queries.

We can supply systems to meet all project requirements. Contact us today for further information and quotation

Rainwater Harvesting System for Commercial use

Industry today pays for water. In most situations potable water is metered going from mains into relative buildings. For the majority of businesses this is their only source of water as there has been no alternative.

Now there is an alternative source of water available, rainwater.

Typically rainwater is an alternative to public main water for WC’s, vehicle washdown, sprinkler systems, process water and other applications where the water is not used for drinking or bathing.
Studies by the Environment Agency in the UK showed results that a commercial entity can save nearly 70% of potable water thus reducing demand on public mains.

In a lot of projects these can be retrofitted easily and quickly. Tanks vary in sizes depending on population and industry requirements.

We can give specific project advice and quotes on basis of each site by one of qualified Technical Team.

Rainwater cannot be used for bathing or for drinking without further filtration.
Contact us today for further information

Rainwater Harvesting System for Agriculture

Today all agricultural industry is paying for water delivered by mains to their farms. Mostly metered this gives a clear indication of the quantities of water used.

Each farm is individual but the general requirements are all the same. Storage tank(s), grit and leaf filter and if required a pump. Dairy, beef, tillage, horticulture all require water but in different quantities for different applications.

This water can be used to feed animals, vehicle washing, shed washdown and crop watering. Using rainwater as an alternative you are reducing your required potable water from the local authority which reduces your annual overheads.

Each project is individually assessed and our technical team can give the best possible advice on the structure of your water collection based on site visit.

By the results of the feasibility study carried out by DIT Bolton St., Dublin, it stated in its conclusions that on that agricultural project the rainwater system supplied 47% of the water used on the farm.

Rainwater Harvesting System for the Public Sector

Public Sector water usage

On average they say we use approximately 148 litres per person per day through bathing, cleaning, toilets and consumption and this is ever increasing. Focusing on the school environment and toilets alone we take an example.

A Primary School, with an average of 150 pupils and 6 staff where each person would visit the bathroom once taking lowest option of toilet cistern system (6 litres): That would account for nearly 950 litres per day before any other water usage consideration.

Rainwater harvesting is a simple solution to the now increasing price of water which our schools are only realising from the Water Framework Directive. This alternative water source can reduce costs of mains water as the bulk of water used in schools is for toilet flushing.

We have taken a further step and can now offer schools 0% finance on our standard option which is a complete installation and commissioning of a Rainwater Harvesting System over a time period of up to four years.

As the concrete water tanks are underground this product applies to all sections, rural and urban.

Examples of how to score your school water consumption can be found on websites such as Waterwise

We can supply systems to meet all project requirements. Contact us today for further information.

How Rainman Works

How Rainman the Rainwater Harvesting System works
Rain falls and is collected from your roof via your gullies and downpipes. Usually this would divert to soakaway however the Rainman System is an interruption between building and soakaway.

1. Filter

This is the first cleaning step in the rainwater system – the filter. The rainwater flows from the roof to the filter. Here dirt particles and debris are separated from the water. The cleaned water flows to the tank. The dirt is washed to the sewer or soakaway with a small amount of rainwater.

All new RAINMAN rainwater filters have stainless steel inserts, which are easy to remove and to clean. They also have a lifetime guarantee and will not need to be replaced. We supply a range of filters to suit all applications.

2. Calmed Inlet

The clean water filtered is stored in a concrete underground tank. By using an underground tank, the water is stored in dark and cool conditions. Here the second cleaning step takes place the rainwater Calmed Inlet supplies lower layers of the stored water with oxygenated water. This oxygen rich water prevents anaerobic reducing conditions forming in the storage tank and the water stays fresh.

3. Overflow Siphon

Any particles that are lighter than water (e.g. flower pollen, dust) float slowly to the water surface. The expertly designed new RAINMAN overflow siphon, with a skimmer effect, removes this floating layer. The regular overflow from the storage tank is important to get the best water quality. It prevents souring of the water. The floating layer could otherwise prevent oxygen diffusion at the water surface, which could lead to anaerobic reducing conditions in the tank, and the onset of odour problems.

4. Floating Pump Intake

The pump intake floats suspended just below the water surface where the cleanest water lies, the water is then abstracted by the pump from this position. A ball float, filled with air, suspends the intake valve, which has a further filter. Usually the Floating Pump Intake has a check valve

5. Submersible Pump

The Submersible pump can pump the water directly to the point of use, or pump up to a header tank in the attic. The pressure of the pump will keep at 1 BAR and up to a maximum of 4 BAR, then the pump will start operating automatically as the pressure in the line drops. When a tap is turned on, it will restore the pressure in the pipe. It will then pump 20-80 litres/minute up to a maximum head of 30m.

6. Mains Tops Up

The function of the mains top up is to allow mains water, where available, to top up the tank when the water level drops to a minimum level. The system will allow approximately 200 litres at a time into the tank until rainwater enters the tank again. The mains top up system also prevents any water being siphoned out of the RAINMAN tank which can happen in other rainwater systems.

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