Rain Water And Waste Water Management

Advanced Heating & Plumbing Plus is involved in all aspects of the Rainwater harvesting and Greywater recycling industry through ongoing relationships with key players within the industry, maintaining Free water at the cutting edge of system technology.

Advanced Heating & Plumbing Plus intelligent rainwater harvesting systems have been created to cater for the specific requirements of the Irish market, providing complete system solutions for every application. Developed in response to water supply, demand and disposal problems which face both homeowners and businesses alike.

Free Water

The Free water philosophy is to supply a complete system package, pre-assembled where possible, made easy to install using high quality components for maximum longevity.

Rainwater harvesting is typically defined as being water collected from roofs via traditional guttering, through down pipes to an underground tank(s). Delivered on demand by an in-tank submersible pump direct to toilets, washing machine and outside tap use. More than 50% of mains water can be substituted by rainwater.

Rain Water Harvesting

Greywater recycling is typically defined as being water from the bath, shower, wash hand basin. The ideal situation for ‘Greywater’ is in living accommodation where sufficient amounts are generated daily for reuse in toilets, washing machine and outside tap.

Rainwater Harvesting – How does it work?

Did you know collecting and using rainwater reduces surface water by 60% per house plot?

Rainwater falling on the roof flows along gutters through down pipes into the tank, via the integrated filter, removing unwanted particles from the rainwater. The filtered fast flowing oxygen rich water is directed down through the calmed inlet to the bottom of the tank where it is deflected upwards oxygenating existing tank water, ensuring a natural biological process takes place

On demand the in-tank submersible pump delivers the clean rainwater to toilets, washing machine and outside tap. The system also has an automatic mains water tank top up facility, ensuring a constant water supply even when the tank rainwater levels are low.

The in-tank filter does not obstruct access into the tank and captures almost 100% of the incoming rainwater. The polyethylene holding tank is manufactured specific to purpose, is of robust construction and ready fitted out with calmed inlet, filter and siphon overflow. Tank has push fit connections and telescopic entry access for adjustment to finished levels.

Domestic Greywater Recycling Benefits

We require water to survive just as we need oxygen to breathe. At present the daily average per capita consumption of water in Ireland totals 129 litres . To limit our consumption of water would mean to reduce the quality of life. Who would turn off their taps voluntarily?

During the same period, fiercely discussed petrol prices only went up 35%. As long as you don’t have to pay every time you use water you don’t worry about the cost of it.

Only recycling saves water in an intelligent way:

No loss of comfort, no limitations.

Our domestic greywater recycling system cleans your water from the shower and bath without the use of chemicals, purely bio-mechanically, and produces water which  meets the strict E.U. Directive for clean Recreational Water. Water that’s perfect for your laundry, to flush the toilet, for domestic cleaning purposes, to wash your car, sprinkle the lawn or water your flowers.

Result: You’re saving without limiting your water consumption or habits.

You can lower your water consumption by more than 50% – thanks to the double use. A family of four to five has a saving potential of up to 90,000 litres of water or more annually, as well as cutting your household expenses. At the same time you are contributing towards the conservation of a precious natural resource. It’s a good feeling and the best formula to enjoy every litre of water in the future.

Water – the big picture

Rainwater – the free & available resource

Collection and use of rainwater would appear the obvious way forward in reducing mains water demand and surface water run off. Rainwater is clean, free, requires no transportation and arrives on a fairly regular basis in most parts of the ireland.

Water – a precious natural resource

Water is becoming an increasingly precious natural resource. Whilst we appear to have an abundant water supply 97% of the 1.4 billion cubic kilometres of water on Earth is sea-water, 2.7% of the remaining 3% is permanently bound up in ice at the poles. This leaves only 0.3% of the Earth’s water resources as usable fresh water. This available water moves in a permanent cycle through evaporation and rainfall. There are also problems with the quality of drinking water as increasing water pollution caused by nitrates, phosphates, pesticides and other chemical substances is making purification increasingly difficult and expensive.


Worldwide water conservation devices are being employed and developed to combat water availability problems. Ireland is no exception. There are distinct water demand, supply and disposal problems facing water companies, developers and home owners alike that may present serious short and long-term challenges for the future. Rainwater Harvesting could be employed to help alleviate these challenges. Surface water, (a large body of unwanted water to be disposed of quickly) is currently causing flooding to unprecedented levels, not previously seen. A little known fact is that for every 10% development of an area, ‘Surface Water Runoff’ increases by 50%. Therefore to collect and use significant amounts every day on new developments would make storm water a social rather than a weather driven event.

How do Rainwater Harvesting Systems work?

This separate system collects rainwater from the roof via gutters and down pipes through a gravity type filter into an underground tank. This initial filtration takes out larger particles from the rainwater. The oxygen rich water then flows into the tank through a calmed inlet, where a second biological purification takes place. There are various other components inside the tank necessary to guarantee good water quality. A submersible pump in the tank delivers rainwater to the various applications, an automatic change over to mains water in times of low rainwater prevents any discomfort to the user.

Roof material

Most common roof materials are suitable for rainwater collection, slate concrete or plastic. A pitched roof is generally better than a flat roof as this reduces evaporation. However both pitched and flat roofs are acceptable. Wire balloon gauze type filters should be fitted in the top of down pipes at the end of gutters to prevent larger debris, leaves, twigs etc from entering the tank, after which there are minimal traces of contamination in the form of organic material that flow from the roof every time it rains this material is separated out by a special gravity type filter.


Various filter systems exist but few work in a positive way with rainwater systems. The most important factors to consider are that the filter must not retain any dirt particles, be self-cleaning and dry quickly after rainfall otherwise germination may take place on the filter face. Filters that retain dirt particles such as sand, gravel and basket types require regular cleaning. Pressure type filters, charcoal etc should be avoided as they place an undue load on the pump, reducing longevity.

The latest and most advanced filter designs are integrated into the tank, the best of which is a gravity type two-step cross flow self-cleaning filter with pressure wash cleaning system, the filter collects almost 100% of the incoming rainwater. The second stage takes out larger particles, grit etc; the second takes out any remaining smaller particles. Because no wet dirt remains on the stainless steel filter face, the filter dries out quickly after rainfall ensuring that germination cannot occur.


The quality of incoming rainwater is very good; to maintain and improve this we have certain components in the tank. The tank is installed below frost depth where the stored oxygen rich water is kept below 10º C and protected from light, ensuring non-growth of algae etc.

Water quality

Rainwater flows into the tank via a calmed inlet, oxygenating the tank water by directing the fast flowing incoming rainwater upwards towards the surface every time it rains and also prevents sediment on the floor of the tank from being disturbed. There is a natural separation of any remaining incoming dirt particles, the heavier particles sink and the lighter particles float on the surface. Studies have shown that sediment on the floor of the tank is minimal, never needing to be cleaned out and causes no risk to water quality. When we have oxygen rich tank water a further natural biological cleaning process takes place. Rainwater is now cool clear colourless and odourless.

The floating layer could be a problem and would hinder oxygen circulation. However optimal tank sizing guarantees the tank to overflow a number of times each year through a special overflow siphon with rodent barrier, skimming off this floating layer. The third in-tank component is the submersible pump with floating extraction hose connected to the suction side of the pump extracting the cleanest water from 15 cm below the surface.

Many European tank manufacturers produce specialised polyethylene rainwater tanks to meet the demands of this technology, they are made from virgin polyethylene of robust construction, heavily ribbed, have push fit pipe connections, telescopic access dome to finished levels and internal inlet, filter and overflow pipework ready fitted.


The pumps are specific to use and made of high-grade stainless steel and brass with low noise characteristics, maintenance free, corrosion resistant and suitable for continuous operation and of low energy use to ensure water cost savings are not spent on electricity for the pump.

Drinking water supply

The main problem to overcome is to supply mains water to the system when rainwater is not available. As cross connection between the mains and rainwater systems is unlawful the water industry demands an air gap between the mains and rainwater supply that must be twice the diameter of the mains water pipe and not less than 20 mm. When rainwater is unavailable a small amount of mains water is automatically fed through a solenoid valve and air gap tun-dish directly into the rainwater tank to maintain a minimum level.

Design Hygiene Aspects

The water quality in rainwater systems has to fulfill European regulations for recreational bathing water (76/160 EWG).

Scientific studies and reports were undertaken to determine the quality of collected rainwater from the roof. There were two main areas of examination. Firstly the rainwater in the tank was microbiologically analysed. The results showed that concentration of pathogen germs in all samples taken were of no hygienic risk for use in toilet flushing, clothes and car washing and garden irrigation.

Secondly studies were carried out comparing the quality of clothes washed in both mains water and rainwater. The results showed that there was no difference in quality between the two.