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Guernsey Water's property assets include water treatment works; raw water storage reservoirs; raw water, foul water and surface water pumping stations; service (treated water storage) reservoirs; a water tower; wells; an operational depot; a wastewater treatment centre; three sea outfalls; many kilometres of foul and surface water sewer, and raw/treated water main; and various other pieces of property and land.

Key Facilities


Belle Greve Wastewater Centre Belle Greve Wastewater Centre

The Belle Greve Wastewater Centre (BGWwC) receives 99.7% of all sewage flows from the island. Flows receive preliminary treatment through state-of-the-art mechanical screens, which remove any non-biodegradable matter from the flows that is larger than 6mm in diameter. The remaining biodegradable elements are then discharged out to sea through the long-sea outfall where tide movement, dispersion and sunlight break them down into harmless elements. The site also contains a stormwater tank which is capable of holding up to 4,000m3 of flow - this means that during heavy rainfall events when the long-sea outfall is at full capacity, the emergency short-sea outfall is much less likely to be utilised.


St Saviours water treatment works St Saviours WTW

Our St Saviours site encompasses a key water treatment works, the Island's only impounding dam and a large reservoir encircled by the popular 3km-long Millennium Walk. The treatment works utilises membrane technology to produce the highest possible quality of water to serve the south of the Island. The membrane technology works by forming a physical barrier to prevent any impurities, such as bacteria and parasites, from entering the water supply and reduces the amount of chemicals required in the filtration process. At full production, the plant can produce 10ML/d (10 Megalitres or 10 million litres per day).


Juas WTW Juas WTW

Juas WTW was recently refurbished and put back into public supply in early 2019. The works utilises dual media filtration and is also home to a UV disinfection system. The works is designed to be able to supply up to 10million litres of water a day at maximum output. The refurbishment itself was carried out in majority by Guernsey Water staff. One of the Island's largest water storage reservoirs can also be found onsite, with a capacity of 609 million litres of water.


Kings Mills Water Treatment Works Kings Mills WTW

The third of our water treatment works, Kings Mills utilises the more traditional method of sand filtration to treat the water, which results in very high water quality production. After undergoing a major refurbishment in early 2013, the plant is now more resilient and acts as a very capable back-up to our other two plants. Kings Mills is able to produce 9 ML/d at maximum operating capacity.


Water Tower Water Tower

Our iconic Forest Road water tower. The tower's purpose is to hold treated water and keep it at a high standard until it is required by customers. By doing this, it essentially smoothes out the peaks and troughs of customer demand. In order to maintain the quality of the water held in the tower, it is occasionally mixed and dosed with chlorine, which keeps the water safe while it travels through our network of distribution pipes to customer homes. The tower can hold up to 0.53ML (530,000 litres).


Forest Road Service Reservoir Forest Road Service Reservoir

In addition to the water tower, our Forest Road site also contains two service reservoir tanks. The difference between 'storage' and 'service' reservoirs is that storage reservoirs hold raw (untreated) water before it is transported to a water treatment works, whereas in a service reservoir the water is already treated, and is being held before being distributed to customer homes. The tanks on this site are known as No.2 (East) and (West). Combined, the tanks can hold 23.4ML of treated water.


Frie Plaidy Service Reservoir Frie Plaidy Service Reservoir

Frie Plaidy, located in the Castel, is the Island's other service reservoir. Like the tanks and water tower at our Forest Road site, the Frie Plaidy tank holds treated water until it is required by customers. The tank here holds 3.8ML of water.


St Andrews Storage Reservoir St Andrews Storage Reservoir

St Andrews storage reservoir is an important site for Guernsey Water. The quarry itself holds 388ML of water, and is in a strategically sound position in the middle of the Island for providing raw water where it is needed. The site also houses Guernsey Water's operational depot, Brickfield House, and a storage unit for wastewater assets.


Grosse Hougue reservoir Grosse Hougue Storage Reservoir

Grosse Hougue is another one of our large storage reservoir quarries located in the north of the Island. The quarry can hold 336ML of water.




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