GW1 Undersink Water Filter Replacement


Ensure you continue to have the best quality drinking and cooking water in the home by replacing your GW1 inline undersink water filter.

The Glacier GW1 undersink water filter is our flagship and most popular unit and it is an invaluable kitchen appliance which will completely transform your drinking water for another 3 years approximately. Did you know – vegetables retain up to 40% more vitamins when cooked in filtered water?

Click an option below to buy online.


Key Features of the GW1 Under Sink Water Filter

  • Our flagship and most popular water filter.
  • This undersink water filter replacement is environmentally friendly.
  • High performance, up to 3 year system.
  • Installed directly on the water line to your kitchen tap or a separate tap on the side of the sink.
  • Most suitable for 3+ person households.
  • Extensive 5 stage undersink water filter.

Get your water filter replacement from Glacier Water Systems, Ballymena.     Get your water filter replacement from Glacier Water Systems, Ballymena.

Installation of My Replacement GW1 Under Sink Water Filter

  • If your current water filter has plastic fittings, your replacement has simple push, quick-connect fittings that allow a seamless replacement process.
  • If your current GW1 water filter has brass compression fittings, please ensure you select this option in the drop down. Ideal for previous NSA water filter users!
  • Our undersink water filter replacement is compatible with many other water filter brands.
  • All our water filter replacement orders are dispatched with full DIY instructions.

FAQs on Replacing Your Water Filter

Why do I need to change my water filter?

Like any type of filter (car, air, oil etc), they eventually clog and stop working – they need to be replaced to maintain optimal performance.

The GW1 water filter is installed to remove chemicals and impurities. Those chemicals and impurities are absorbed into the carbon in the water filter. After approximately 3 years, the water filter will be saturated with those contaminants. Although water will still come through your tap, there is a substantial risk of leaking chemicals and bacteria back into your drinking water.

My water is ‘clean’, why do I need to change my water filter?

The question is less to do with the quality of the water or how “clean” it is – your water filter also filters out dirt, sand, sediment which will eventually clog your water filter.

I can’t taste the chemicals coming through my water filter, does it still need changed after 3 years?

Just because you can’t taste the likes of chlorine and heavy metals in your water doesn’t mean it is ok to drink. We also recommend the GW1 under sink water filter is replaced after 3 years because bacteria will have started to grow and it will be leaking into your water.

Is this just a money making thing?

The amount of filtration that your water filter can do is based on volume of water, science and number of people in a household, not £s. The GW1 water filter has the capacity to filter approximately 42,000 litres of mains water, which an average household will use generally within 3 years. 

Changing your inline Glacier GW1 water filter is much more cost effective than spending money on cartridges that need changed every month or every 6 months.

Filtered water for all the family for only 23p per day

Initial Cost


Replacement after 3 years


That is only

£80 per year

£6.66 per month

£1.66 per week

Clean, fresh, filtered water for only

£0.24 per day

My water flow from my water filter is slow, does this mean I need to change the water filter?

Yes this could be because your water filter needs changed. This will happen over time as your water filter will clog with sand, dirt, bacteria, chlorine and other contaminants. 

Continue to have:

Filter your water with Glacier Water Systems for great tasting water. Filter your water with Glacier Water Systems for a healthier you. Filter your water with Glacier Water Systems for fresher cooking. Filter your water with Glacier Water Systems for tasty hot drinks.

I need my whole GW1 water filter filter kit replaced from Glacier Water Systems, Northern Ireland.


For more technical information, please download the PDF Specification for the GW1 Water Filter






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