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Case Study


We have a clean filtered supply of drinking water on board.

[Case Study written by David Hutchinson]

Do you carry large containers of mineral water when cruising? Are you afraid to drink the water that comes from your water tanks?

Well we did and we were. Large 5 litre containers were stowed in the galley aboard our Princess 430 motor cruiser AquaVit, but these provided us with a safe and secure drinking water supply whilst cruising, and ashore in the marina. However they were cumbersome and inconvenient.

We generally used our 560 litres of fresh water in our tanks for washing up, showering and general cleaning tasks. We always treated the water using AquaPur liquid – this did a fine job but, depending on the dose used, left the treated water with a slight chemical smell and a little eye soreness when showering. We occasionally risked having filtered water (from a Britta jug using a carbon filter).

Around two years ago we had fresh water flush installed on our boat and despite all the assurances that there was no back flush into the fresh water supply we were not prepared to take any chances. One dose of E Coli was not worth the risk. All of the water we drunk – boiled or not – came from containers that were filled with mineral water -- at great inconvenience and continuing expense.

We decided to investigate the effectiveness and cost of drinking water filters.

Choosing the water filter

A convincing display at the Southampton Boat show, followed by some research, persuaded us to buy and have fitted a Seagull IV X-2KF drinking water purification system provided by an extremely helpful General Ecology Europe Ltd, based in Crawley. This organisation provides water filter systems for major airlines – who take on water from all over the world of varying quality -- and major boat brands such as Fleming and Sunseeker.

Our considerations for selecting a suitable system were

  • the method of and effectiveness of purification
  • the taste of the end product
  • the flow rate through the filter
  • the ability of the filter to withstand periods of no use
  • how often the filter has to be changed
  • the cost of the unit and the filters
  • the ease and cost of fitting

The unit we selected is an ultrafine microstraining purification device that traps and holds contaminants and tiny particles. This does not involve filtering through carbon. It removes chlorine and other chemical contaminants. It also removes harmful bacteria and viruses that lead to illness, like E Coli, Campylobacter, Salmonella and Listeria. The filter also removes algae, fungi, amoebic cysts, microscopic worms and other undesirable ‘life’. The test data is impressive.

Water kept in tanks can often be tainted with foul tastes and odours. The filter removes them all leaving a fresh, clean water to drink.

The unit we selected has an exceptionally good flow rate (7.6 litres per minute) and is delivered via an attractive, stainless steel, dedicated tap in the galley. Smaller, less expensive but equally effective units are available in return for lower flow rates.

Some systems continue to provide water when the filter is no longer effective. However with the Seagull the flow rate reduces when the filter is nearing the end of its lifecycle, ensuring safe filtration at all times. But that will be after around 7600 litres have been purified. Based on 1.5 litres per day per person that is over 1200 days of water for a family of four.


The unit we bought was easily fitted – it required no power to operate it. The kit consisted of

  • the filter (a stainless steel cylinder around 14 cm tall and 17 cm diameter, including fixings)
  • the tap
  • two hoses (inlet and outlet)
  • suitable fixings for installation

We located a space for the filter in the cupboard directly under the sink. The unit fitted neatly into the corner, leaving plenty of access to it but having minimal impact on the storage space available.

The mounting bracket was fixed.

The main concern was fitting the dedicated tap. This involved drilling a hole in the corian work top. However our preferred service provider, Landau UK Ltd, ( had plenty of experience doing this – so we let them get on with it! As usual they did an excellent job. We selected the tap location, tape was used to protect the surface.

The hole was drilled, and a thick plug of corian and wood was removed very neatly.

The tap was then fitted, the supply hose was attached and hey presto, after around two hours installation, the filter was working.

This has been a major improvement to our boat. We no longer have to carry plastic water containers, we can take water on board from marinas at home and abroad without having to be too concerned about water quality – we can be sure that even with the fresh water flush that no contamination will be present in our filtered drinking water.

The water has a great taste. Containers are a thing of the past for us! As well as fixed units this company also provides a range of portable water filters, perhaps ideal for ribs and day boats.

Sources of information

The Seagull IV water purifier was supplied by
General Ecology Europe Ltd
St Andrews House, 26 Brighton Road, Crawley, West Sussex, RH10 6AA
Tel: 01293 400644

The unit was installed by
Landau UK Ltd, Swanwick Marina, Southampton SO31 1ZL

Tel: 01489 577588

Retail price of unit is around £550, but we managed to get a very good show price! Smaller units cost in the range of £190 to £319. A replacement filter costs £104.