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Heavy Duty Twin Outdoor Caravan Water Filter System | WaterMark Certified (GT1-4WM)

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Quick Overview
  • Ideal for Pre-filtering Water BEFORE it goes into your Main Water Storage Tank
  • Sturdy Pre-Assembled Bracket for Convenient Mounting to your Caravan's Exterior or Interior
  • Your Choice of 2x Filters (See Below for More Info About Filter Combo Options + Prices)
  • Can be Plumbed-In or used with Standard Garden Hose Fittings
  • Fully Watermark Certified & Compliant with the Plumbing Code of Australia
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Heavy Duty Twin Outdoor Caravan Water Filter System | WaterMark Certified (GT1-4WM)

  • Ideal for Pre-filtering Water BEFORE it goes into your Main Water Storage Tank
  • Sturdy Pre-Assembled Bracket for Convenient Mounting to your Caravan's Exterior or Interior
  • Your Choice of 2x Filters (Optional Extra)
  • Can be Plumbed-In or used with Standard Garden Hose Fittings
  • Fully Watermark Certified & Compliant with the Plumbing Code of Australia
  • Heavy Construction Housings tested to 120psi.
  • Suits Standard Australian Sized 10" x 2.5" Water Filter Cartridges.
  • Note that these housings are BLUE meaning they are suitable for outdoor use. Don't be fooled into buying white housings for use outside as they are not UV resistant!
  • Dimensions: Height: 365mm (Allow 1" space below for filter change if mounting), Width: 280mm (Without Fittings), Depth: 165mm
  • See below for information about which filter combination to choose to suit your needs

Kit Contains

  • Heavy Duty Watermark Certified Twin UV Resistant 10"x2.5" Filter System with Bracket
  • Opening Spanner
  • Instructions
  • Your Choice of Filters (Optional Extra - See Below for More Info About Filter Combo Options + Above Drop Down Menu for Pricing)

Due to popular demand and ongoing feedback from Caravaners, Nomads and Travellers all across Australia We have decided to release the Twin Caravan Water Filter System.

Some cheaper versions of this original system are not supplied fitted with a suitable, sturdy mounting bracket. The result of this is a huge stress on the centre joiner, which in turn can cause leakage and even complete failure of the joiner. Can be externally mounted or plumbed in. Whilst it can be plumbed in, this is only recommended for internal installation. If used externally, detach the system when in motion to avoid damage. 

The port sizes are 3/4" for high flow to 45 LPM, however, to maximise the efficiency of the carbon cartridges for drinking water purposes, you should not exceed 15 LPM.

Please note: under no circumstances should a thread sealant be used on water filtration housings – thread
tape ONLY is permitted. If thread sealants are used, all warranty is void.

WaterMark Certification

This Water Filter System is certified to WaterMark Standards AS/NZS 3497 under Certificate Number 23247. WaterMark certification is the level of certification required by law for a licensed plumber in Australia to install a water filter system. All products used under this certification will give you peace of mind knowing that your water filter complies with Australian plumbing codes.

Our WaterMark certified filter systems are hand assembled here in Australia and are randomly batch tested to ensure top quality and workmanship for your water filtration products.

Filter Combinations

Silver Impregnated Carbon (For Mains or Rain/Potable Bore Water*)

Whilst carbon effectively removes odours and taste issues from water, carbon ash is a source of nourishment for bacteria, and unfortunately, carbon filters can quickly biofoul if left in wet and warm conditions. Silver-impregnated (bacteriostatic) carbon, however, prevents biofouling and extends the life of the filters, as it immobilises the respiratory activity of the bacterial cell and prevents bacteria from breeding in the filter. The Silver Carbon filter combo is therefore suited to applications where the system may not be frequently in use for periods of a week or more. Recommended for use with rainwater/caravan use for the convenience of not needing to be prematurely changed due to bacteria growth. 

Heavy Sediment (Not for Drinking)

These filters are suitable for water that is visibly dirty and there are signs of heavy sediment. The pre-filter is a 100 Micron Mesh Strainer for easy washing/re-use. The secondary filter is a 20 micron washable also which should produce clearer water. These filters are ideal for tank filling or running the toilet. Additional filtration/sanitation is required for drinking.

Filter Information

Customise your filter system set up to suit your unique needs. Please read the below for a full breakdown of which filters to choose, and why*.

*Please note - the below recommendations are general information only and may not always suit your requirements. Please call us on 07 5597 4585 prior to purchase if you have any questions about your requirements.

Sediment Filters

  • Choose from pleated (washable) or polyspun (disposable) sediment filters. 
  • 0.5 to 5 Micron is well suited for mains/town treated water and high-quality tank/rain** water.
  • If you are expecting a lot of sediment, consider upgrading to a Triple Caravan Filter System which allows you to place a pleated filter first, followed by a poly spun with a final carbon element.

Tank and bore** water are often contaminated with sticks, leaves, and rock sediment. However, you'd be surprised just how much sediment - such as sand, dirt, clay, silt, and even rust particles - can make its way through municipal water supplies! In some cases, finely dissolved matter can even cause visible discolouration, build up and staining, along with a foul taste and odour - and even a gritty texture in some rare cases! Installing a sediment filter also filter helps protect your pipes and pump from getting clogged, and can also help to protect your carbon filters from getting blocked up with ultra-fine silt. When it comes to which size micron rating to choose, the rule of thumb is: smaller the micron rating, the finer the level of filtration. 

Pleated (Washable/Reusable) Sediment Filters

    • Larger Surface Area Catches More Debris
    • Reusable/Washable
    • Ideal Pre-Filter for Tank/Rain Water*

Pleated filters carry a much larger surface area than polyspun filters, and therefore they are able to catch a lot more debris. Simply remove the filter, clean, and re-use! Very popular for tank water when you have a lot of debris like leaves and dirt, particularly after a fresh rain. Pleated filters are also useful for bore water when you have a small amount of iron or manganese present, as pleated filters are easy and quick to clean. The washable pleats on this filter are designed to be washed and reinstalled. However, please consider that if this is drinking water you need to be careful not to overuse a pleated filter, because it will eventually gather bacterial contaminants and incur micro-tears. If the water isn't all that bad you might want to consider using a polyspun disposable filter and replace it when dirty. 

Pleated Filter Options:

      • 100 Micron Washable Cartridge
      • 20 Micron Pleated Washable Sediment Filter Cartridge
      • 5 Micron Pleated Washable Sediment Filter Cartridge

Poly Spun (Polypropylene) Disposable Sediment Filters

    • High Flow & Low Pressure Drop
    • Cost-Effective & Disposable

Poly Spun filters produce a high flow and low pressure drop, and do not accumulate bacteria as much as other materials. They are highly cost-effective and disposable. All of our poly spun filters are made of 100% Virgin Polypropylene. Polyspun filters are manufactured to create a gradient density that allows for excellent sediment-holding capacity and filtration efficiency.

Polyspun Filter Options:

      • 0.5 Micron Polyspun Sediment Filter Cartridge


Pure Brand 100% Coconut Carbon Filters

  • High Quality, 100% Coconut Shell Carbon that Produces "Sweet" Tasting Water
  • Excellent Contaminant Reduction Capacity for Common Water Additives such as Chlorine, Trihalomethanes and Volatile Organic Compounds
  • Recommended 12 Month Lifespan if Used on Municipal Treated Water
  • Designed for Minimum Impact on Water Pressure

The perfect carbon block filter is made from 100% Coconut Shell Carbon, which creates what many believe to be the sweetest tasting water. The unique pore structure of this carbon is well suited for chemical absorption, including VOC's, while reducing chlorine and chemicals that contribute to taste and odour. Coconut Carbon provides a much higher volume of micropores than coal, wood, or lignite-based carbon. Thus, resulting in a more effective removal of trihalomethanes (THMs) from municipal water supplies. The larger surface area provides a more effective method of filtering common contaminants such as chlorine and chloramines. The unique raw material of the coconut shell and the carbon manufacturing process ensures exceptional hardness and low ash content.

Pure Brand's 100% Coconut Carbon Block Filters are made from a combination of high-performance coconut shell carbon, unique binders, and industry-leading manufacturing processes to deliver supreme-quality filtration. Expertly designed and manufactured, these filters deliver exceptionally low-pressure drop, resistance to sediment build-up, and excellent contaminant-reduction capabilities. Pure Carbon Blocks are registered in compliance with NSF/ANSI 42, 53, and 61 for several things, including VOCs, THMs, Lead & Heavy Metal Reduction, Chloramine Reduction & Chlorine Taste & Odour reduction. This also includes meeting incredibly high standards of purity and safety in the materials used.

Please see below for a full comparison of the Carbon Filters we recommend for use in our Caravan Filter Systems:

GT4-6CTO - 1 Micron Chlorine Taste & Odour Reduction Coconut Carbon (For Improved Chemical Reduction on Mains Water)

    • CTO Carbon is our standard recommendation for chlorine reduction, improved sweet taste and reduced odour - great value and quality!

Chlorine is generally the biggest concern for those on municipal water or those who use chlorine to disinfect their tanks, due to the offensive chemical smell and taste it produces, along with potential health effects resulting from topical exposure or consumption. Whilst Chlorine is effective at sanitising bacteria and viruses, Volatile Organic Compounds and Disinfection By-Products such as Trihalomethane (THM) and Chloroform can form when chlorine reacts with oxygen and other chemicals in solution. The Chlorine, Taste, and Odour cartridge will provide you with clean, great-tasting water free from nasty chemicals and remove or reduce any chemical smells in the water caused by free chlorine.

GT4-3LRC - 0.5 Micron Lead Reduction Composite Coconut Carbon (For Chlorine Reduction & Heavy Metal Concerns in Rainwater, Old Infrastructure, Cities & Industrial Areas)

    • Dual Reduction of Chlorine and Heavy Metals.
    • Ideal for Filtering Tank/Rain Water** or Mains Water.

Constant exposure to heavy metals combined with the different chemicals being used to treat our water supplies can have serious health effects, and can also cause severe plumbing problems within our homes. Rainwater (acidic pH) and chlorine/chloramine treated water (basic pH) both tend to be quite corrosive, and this can wreak havoc on the internal plumbing and fixtures within old municipalities and even the copper and brass fixtures in your home (which fittings may contain traces of lead)! Rainwater is also commonly contaminated with heavy metals - especially in cities and industrial areas. On this basis, it is also not uncommon to have elevated heavy metal levels in treated mains water supplies. 

This cartridge is perfectly suited to reducing trace heavy metals that may be present in your water. The technologically-advanced Lead Reduction Cartridge is impregnated with BASF ATS Lead and Heavy Metals Adsorbent Media, which features a high capacity for the reduction of Lead and other heavy metals such as Arsenic, Chrome, Copper etc., along with the usual benefits of carbon in the reduction of Chlorine, Volatile Organic Compounds, and Trihalomethanes.

GT4-58BCC05 0.5 Micron Bacteriostatic (Silver Impregnated) Coconut Carbon Block (For Preventing Filter Biofouling in Mains and Tank/Rain Water***)

    • Prevents Bacteria from Proliferating within the Cartridge.
It's important to note that Silver Impregnated Carbon is BACTERIOSTATIC - meaning that it inhibits or prevents the increase or growth of bacterial levels WITHIN the filter only. Silver Impregnated/Bacteriostatic Filters DO NOT sanitise, disinfect or remove bacteria from water. If this is your goal, further treatment is required - please refer to the note at the bottom of this page **FILTERING TANK AND BORE WATER - IMPORTANT INFORMATION BEFORE YOU ORDER**.
Contrary to popular belief, carbon does not filter out bacteria. Whilst carbon effectively removes odours and taste issues from water, carbon ash is actually a source of nourishment for bacteria, making wet carbon filters a breeding ground for microbial contamination (Note: this should not be an issue on mains water as Chlorination is designed to kill bacteria). This, unfortunately, causes biofouling of the filter cartridge which can lead to premature blockage (costing you hundreds of dollars to replace cartridges more frequently than you should have to), putrid tastes and odours and worse - illness as a result of ingesting the bacteria that has passed through the cartridge and into your drinking water! Using a rotten filter can make you seriously sick - so if in doubt - chuck it out!
Silver Impregnated Carbon, on the other hand, is bacteriostatic - meaning that it is proven to inhibit the growth of carbon-fed bacteria within the filter to prevent bio-fouling and prolong the life of a cartridge - even while it is not being used! Therefore, when it comes to filtering raw water, Bacteriostatic (Silver Impregnated) Coconut Carbon is the number one choice, as this media is specifically designed for use with rainwater, tanks and bores* to prevent bacteria from breeding and colonising within the carbon and extending the life of your filter. Silver Impregnated Carbon is ideal for periods of time where the filter may go unused. If you want to get the most out of your carbon filter, you can even go one step further and dry it out between uses! 

So, how does Silver Impregnation inhibit the growth of bacteria in a carbon filter? When bacteria come into contact with silver, the silver ions puncture the bacteria's cell membrane and wreak havoc by binding to and denaturing the bacteria's DNA. The sulphydryl group already within the bacterial cell also reacts with the silver, producing a silver sulphur complex that immobilises the respiratory and reproductive activity of the bacterial cell. Interestingly, Silver Impregnation has an incredibly long-lasting effect, as the dead bacteria then leach the silver molecules back into their environment, effectively killing neighbouring live bacteria as they die.

Dead bacteria store the microscopic silver particles within their cells (see above image of dead bacteria with silver nanoparticles (white spots), making them deadly to live bacteria.
(Source: "Antibacterial Activity of Silver-Killed Bacteria: The "Zombie" Effect" (2015), https://pubmed.ncbi.nlm.nih.gov/25906433/).

Filter Replacement Packs & Schedule

Caravan filters are recommended for replacement every 6-12 months, or as required. Please see below for the links to the full replacement packs for this system:



Disclaimer: Do not use or drink microbiologically unsafe water or water of unknown quality without adequate disinfection. 


FSA’s Recommendation for Caravans, Campervans + Travellers on Rain/Tank/Potable Bore Water*

If during your travels you will ever use Rain/Tank Water and Potable Bore Water (*i.e bore water that has been tested to the Australian Drinking Water Guidelines and deemed suitable for drinking purposes per the Guidelines’ aesthetic, health and safety recommendations), please see below our recommended filtration schedule to ensure safe drinking water:

  1. External Sediment + Carbon Pre-Filtration to Prevent Tank Clogging + Improve Initial Taste & Odour
  2. Tank Dose with HydroSil Ultra 7.5% for Protection Against Bacteria & Viruses
  3. Undersink <1 Micron Absolute Filter for Protection against Parasites & (Optional) Coconut Carbon for Improved Final Taste & Odour

Read on for a full explanation of why we recommend this as the minimum standard of filtration for treating Rain/Tank/Potable Bore Water for drinking purposes.


For Protection Against Bacteria/Viruses

Bacteria (such as E.Coli) can colonize in stagnant water and result in harmful illnesses when consumed.
For sanitation against common water-borne bacteria/viruses in rainwater and potable bore water*, we, therefore, recommend dosing your tank with a product such as Hydrosil Ultra 7.5% Water Sanitiser to ensure protection against microbiological contamination/biofouling in your pipework and/or filter system.

HydroSil is a food-grade silver and hydrogen-peroxide based water sanitiser, which acts to oxidise bacteria and viruses without leaving any dangerous residues behind. HydroSil sanitizes and protects your tanks and water storage devices, making rainwater and potable bore water* safe and suitable for human consumption. HydroSil is not a chlorine-based chemical like most sterilisers on the market today. It is non-toxic, and safe to use around your home and family.

Dosage Rate: HydroSil should be dosed at a rate of 200mL per 1000L of water.
To scale down to tank size, you will require 20mL per 100L.


Buy Hydrosil Ultra 7.5% Here:


For Protection Against Parasites/Protozoa

Ingesting waterborne parasites (Protozoan Cysts) such as Cryptosporidium and Giardia (which flourish in raw water sources such as rain water tanks and bores), are a common cause of gastroenteritis.

Whilst Chlorine can inactivate Giardia with a moderate dose and contact time, Chlorine has a negligible effect on Cryptosporidium unless dosed in excess of the acceptable Chlorine limit listed in the Australian Drinking Water Guidelines (Version 3.6, pp. 200).

For protection against these common cysts, we, therefore, recommend under sink filtration down to at least 1 Micron (Absolute) or smaller (i.e. with Reverse Osmosis or the Caware 0.1 Micron Absolute 3-in-1 Sediment, Chemical + Bacteria Reduction Filter). Please note: 0.1 Micron Filtration is NOT recommended for use with an External Caravan Filter System.

Such fine filtration, used along with regular sanitation (i.e. with HydroSil Ultra 7.5%) is a cost-effective and safe drinking water solution for rain water and potable bore water*, and is perfect for casual disinfection requirements such as when travelling in a caravan.

Compact Undersink Reverse Osmosis Water Filter System | pH Neutralising (GT1-70Compact)

Compact Undersink Reverse Osmosis Water Filter System | pH Neutralising (1-70 Compact)

Click here to check out our full range of Undersink Caravan Filter Systems! 


Why UV Disinfection is NOT Recommended for Travelling/Casual Use

You may have read that Ultraviolet (UV) Disinfection is one of the safest and most effective methods for treating drinking water, as it has a minimal effect on drinking water’s composition and taste, whilst killing 99.9% of microbiological contaminants. It's true that UV is highly effective at inactivating the DNA cells of water-borne micro-organisms such as bacteria and viruses, and excellent at killing chlorine-resistant parasites such as Giardia and Cryptosporidium.

However, as effective as they are, please note that UV systems are generally NOT recommended for travelling and casual use, for the following reasons:

  • UV Systems require electrical input and typically need to be left on 24/7 to prevent degradation of the UV lamp (not ideal for infrequent use).
  • UV radiation also heats up the UV chamber and, in some cases, requires a constant flow of fresh water and a thermal release valve to release the hot water (which is not ideal on a small water tank).
  • UV Systems also contain fragile glass components (not ideal for travelling).



Width: 280mm (Without Fittings)
Height: 365mm (Allow 1" for filter change if mounting)
Depth: 165mm


Size: 10" x 2.5"
Ports: 3/4" inlet/outlet
Individual Housing Part Number: GT8-4G
Flow: Approx. 30Lt/Min when using standard Sediment Cartridges. Carbon should not exceed 10 Lt/Min
Tested To: 325PSI >> We deem 70 PSI to be optimal.
Suits: Outdoor applications. System is UV resistant

Return Policy

Due to the nature of the products we sell, a strict return policy is in place. We work with food grade certified materials that must be un-opened and un-used as to be able to be re-sold.

You may receive a refund or credit of equal amount, less the restocking fee if applicable and any other deductions that are relevant.

  • Wrongly purchased items may be returned for a merchandise credit, this applies for but not limited to: Wrong size, wrong system etc.
  • 30 Day return Policy: Returns will not be accepted without prior approval or after 30 days of invoice date.
  • All returns will incur a 17.5% restocking fee or cost to send the item to you whichever greater. FSA may use discretion to determine the restocking fee.
  • Any damages (minor, that can be repaired) will incur a fee which will be deducted from the total refund which will be equal to the cost of the replacement
    parts (List Price) and labour charge (if applicable) to repair the system(s). This will be separate to the restocking fee.
  • Any damage considered to be major and not feasible for repair may be refused and the return request will be void. The customer will be responsible for the return freight or disposal of the damaged unit.
  • Return shipping is to be paid by the buyer to the address provided. It is recommended that the customer applies transit warranty to the return freight in case of damage.
  • Any damages to the system that were not reported to FSA within 48 business hours of receipted delivery are not covered under our transit warranty.

  • Should the item appear faulty or doesn’t work how described, the unit/item must be returned for testing (if requested), the return postage paid by the buyer. If the unit/item is deemed to be faulty, compensation will be provided for the postage cost (Proof of cost required). If the unit/item is deemed to be in working order and as described, the buyer will responsible for return postage.

If you have any questions about our return policy, please contact us before purchase. This will also help to ensure you purchase the correct product that suits your requirements.