Choosing a filter for your home and espresso machine

When selecting a water filter for your coffee machine, three key areas of filter performance should be taken into consideration:

  1. Sediment reduction– removal of algal spores as well as small particles of dirt, sand and rust will protect the flow path of your machine. It will also prevent the boiler from accumulating sediment which can form a “sludge” which acts as a catalyst for scale development- and there’s your answer to the age old question: “Why do I need a filter?”
  2. Chemical reduction– reduction of chemicals such as chlorine and chloramines which will negatively affect the taste of espresso as well as having detrimental (corrosive) effects on stainless steel boilers
  3. Total hardness (TH) reduction: This refers to the presence of Magnesium and Calcium salts in the water. Some of these salts can precipitate to form scale. This scale coats boiler surfaces elements, valves, solenoids, gicleurs and water flow paths. Scale buildup can adversely affect water temperature, pressure, steam performance, water flow rate and taste. Whilst scale can be removed by chemically “descaling” the machine, minimising the accumulation of scale with the use of appropriate filtration will dramatically slow the rate of accumulation. Descaling requires the use of acid and this acid will ultimately degrade the thin copper tubing used to link machine components. We do not recommend routine descaling, rather the use of appropriate filtration. 
  4. pH- Ideally, the pH of your water will be close to neutral. Low pH in particular can occur in areas of high TH and TDS (total dissolved solids). Whilst some manufacturers produce buffering filters, there are areas of Australia where they are ineffective due to high TDS and TH. In these areas, bottled and filtered or reverse osmosis (RO) water are the only suitable options.

Whilst most filters adequately achieve the reduction of sediments and chemicals quite successfully, scale reduction is a little more complex. Please note that a drinking water filter as recommended by a plumber of retail store is unlikely to be a softening filter: i.e it will not remove scale. The use of a softening medium in a water filter can achieve a reduction of scale causing compounds of up to 90%.
Water softening is frequently achieved with the use of an ion exchange resin. This process involves the exchange of scale causing Calcium and Magnesium for Sodium. Whilst some Calcium and Sodium compounds are insoluble and deposit as scale, Sodium compounds are generally soluble and pass harmlessly through the espresso machine. Water softening reduces the total hardness of the water to an acceptable level without significant change to the pH of the water.

Total dissolved solids (TDS)

Total dissolved solids is a measure of all dissolved minerals in the water. A reading of over 300 parts per million (ppm) would suggest that a more complex filtration solution may be required to protect your machine. In general, Reverse Osmosis (RO) systems are not recommended for use with home espresso machines unless a remineralising medium is in place as well. RO is energy hungry and and wastes large quantities of water as well. Espresso machines rely on water conductivity to sense the presence of water. RO systems produce water without ionic content. The result is that the machine may not fill or may overfill with water. RO systems may be appropriate in some situations where extremely hard water is present, but only after discussion with a coffee water specialist. Contact us if you would like to be placed in contact with a specialist.


All filtration recommendations here will work will in domestic environments where TH is less than 160 ppm and TDS is less than 300 ppm. Filter cartridges should be replaced every 12 months for health and hygiene reasons.

How do I find out my TH and TDS?

Talk Coffee has testing equipment to TH, TDS. Bring a water sample with you in a drinking water bottle and we can run a quick test for you. Comprehensive tests can be obtained for a small charge at places such as swimming pool chemical stores and aquariums. Your local water authority will also be able to provide general information. Note that water quality varies seasonally, so do ask for upper and lower levels. Our experience is that water quality can vary dramatically from house to house within one street, so the best results will be obtained with a test of your water.

My water is not that hard. Do I still need a filter which softens the water?

The heating and cooling of water in espresso machines is is the primary reason for scale formation. Home use machines are often switched on and off more than machines in commercial environments. This makes scale formation more likely- even in areas where the water is considered to be soft. The smaller boilers of home machines can further accentuate this. Please note that the level of scale reduction can and does vary according to the type of resin used in the filter and the local hardness of the water source. We recommend that regular use of the hot water available from your machine- to heat a cup of for a long black or cup of tea is a good thing. It helps flush scale causing minerals from your machine.

Will a Brita jug from the supermarket or do?

Whilst these claim to soften water, the reality is that they’re good for a few litres at best. These jugs are really just for drinking water.
What about a filter from my local hardware place or one supplied by my plumber?
We can assure you that having read this article, you will likely know more about filtration for espresso than your local place or your plumber for that matter. Both will try to sell you a drinking water filter and in many areas, it’s simply inadequate for your specific purpose.

My machine has a resin softener attached to the inlet hose.

Whilst better than a Brita jug, in our experience, these do little more. The resin can be “refreshed” by removing the filter and soaking it in a tall glass of cold salt water every couple of weeks. We would only recommend these in areas of TDS <40ppm. If installed on your machine, they will not influence additional filtration and can be left in place.
So what about distilled or deionised water or Pureau? I can buy that.
Sorry, not suitable. Espresso machines sense the presence of water via conductivity- so some ionic content is essential or you will ultimately experience problems such as over-filling of boilers or false low water warnings. In addition. these very low ion waters will leech metal ions from your boiler and can ultimately cause damage and/or cause complete boiler failure. La Marzocco’s water calculator web page is a good resource, especially for espresso machines with stainless steel boilers.

Can I help prevent scale?

Yes! If you have a heat exchanger (HX) or dual boiler machine, use the hot water from your machine each day. Heat a cup or make a cup of tea. Many users never use the hot water- effectively removing water vapour as steam and then concentrating minerals in the boiler. This can lead to significant scale deposition even in areas where the local water is quite soft. Using water from your boiler will help dilute scale causing compounds.
Talk Coffee sells a variety of filtration systems to suit espresso machines and provide quality drinking water. If a dishwasher with a cold inlet is in place all can be easily installed by the home handyman. We recommend the Brita C150 Quell and Brita C150 Finest.

What’s the difference between the C150 Quell and C150 finest?

Both of these filters are excellent 3 stage softening filters.

  • Subject to suitable water quality, we strongly recommend that a buffering, softening filter such as then Brita C150 Finest MUST be used with all machines with stainless boilers. It can also be used with Copper boilers
  • C150 Quell has higher capacity circa 3000L v circa 1500L
  • C150 Quell may be mounted horizontally whereas the C150 Finest MUST be vertically mounted.
  • Both should be changed no later than 12 months from installation.

I have an espresso machine with stainless steel boilers. What should I do?
Use a  Brita C150 finest. This filter employs a buffering system to maintain water pH whilst softening water. Conventional filters can lead to acidification of water where TDH is higher. This filter overcomes this problem. We are now recommending that this filter be used wherever possible and always with machines which employ stainless steel boilers. The only limitation of this filter when compared to the C150 purity is that the finest MUST be installed vertically. There are however areas of Australia where the C150 Finest will not be adequate and only bottled water or Reverse Osmosis with remineralisation will be satisfactory for your machine. If you have stainless steel boilers it’s essential that you have your water professionally tested and then choose the right option for your circumstances.

Filtration options:

Areas of low native TDS (<200ppm) and hardness (TH<100ppm) verified by professional test: eg. Melbourne and Sydney:
1. Under sink system with dedicated drinking tap. Brita C150 coffee filtration PLV and tap + connection to espresso machine.
This variant provides unlimited water via a drinking tap. This may be used to fill the tank of your espresso machine and has the facility to plumb an espresso machine if/when required.

  • 3 stage Brita Purity/Brita finest filter for effective sediment, chemical and TH reduction.
  • Blending valve on the head to adjust for softer and harder water areas.
  • DIY install kit – includes all fittings included for standard install (suits any cold water connection mixer tap or dishwasher).
  • Shut off valve on head for easy filter changes
  • Quality Designer ~Gooseneck T Faucet for easy use and long life.
  • Multifunction Pressure Limiting Valve for easy installation & protection.
  • 10 test strips to monitor filter performance in the reduction of TH.
  • Filter suitable for 12 months for most household installations and can be mounted vertically or horizontally.
  • Fits in with most mixer or dishwasher taps(cold)
  • Filter and head measure 42cm long
  • Click here to purchase replacement Brita C150 cartridges

2. I just want to plumb my machine in. Brita C150 PLV kit or Brita C150 Finest with PLV (braided hose version) This kit allows for easy installation to a  1/2″ male tap – making for quick machine installations. It has a 350KPA PLV, 1.5 metres of flexible high pressure poly hose, Purity C150 filter and head assembly. The outlet of the head is 3/8″ male and fits most braided hoses provided standard with most machines

3. I’d like a drinking water tap and to plumb in an espresso machine as well.  Brita C150 coffee filtration PLV and tap + connection to espresso machine. This kit adds a t-connection and stop valve to the above kit to allow for drinking water and an espresso machine connection when required.

4. Upgrade my existing system to a softening solution. Brita C150 upgrade kit.
This kit allows for an upgrade of an existing filter system and comprises of C150 Purity or C150 finest filter, 1/4″ push fit adaptors for poly hose and a bayonet mount. The outlet of the head is 3/8 male and fits most braided hoses provided standard with most machines.
5. I have a filter system and just need to add a softener to it.
Our friends at Fridge Filters can supply a softening kit to add to your filter
6. I need something portable. Aquapro benchtop filtration system
Benchtop Filter System, inc CFS117R Softening Filter 5 Micron
The Aqua Pro Bench system is ideal where plumbing is not the preferred option.
The single housing unit sits neatly next to your sink and connects easily to the end of most faucets. The diverter valve at the faucet means that you can choose between running water through the filter OR just use the tap as normal.
The BCTF-SOFT contains a combination filter that has carbon and cation resin media offering sediment, chemical and softening capacity.
This filter should be changed at least every 12 months.

Hard water areas: (Total hardness (TH) >120 PPM/high Chloride or Chloramine/>200PPM TDS) verified by professional test: Including but not limited to parts of WA including Perth/SA including Adelaide/NT/Western Vic, Queensland including Brisbane and many regional/outback areas.

The key issue is that the high requirement for softening resins can lead to the presence of chloramines as well as acidification of water and this is frequently fatal for stainless steel boilers. A new EU requirement for will ultimately lead to the demise of Copper espresso machine boilers and as a result, filtration for owners in these environment is set to become critical.
Where Total Hardness is less than 70% of the Total dissolved solids (TDS) acidification of water will be minimal and in general, a high quality softening filter will be adequate, but cartridges may need to be replaced more frequently than usual. Where TDS is <250ppm, the Brita C150 Finest is recommended.
In areas of high TDS (over 300ppm) – with low TH means that TH reduction will not resolve some of the issues caused by other minerals. Chlorides may make up some part of the overall dissolved content. Our information is that in cases of high TDS or high  Chloride (>100ppm) and/or Chloramine concentration, mains water will require reverse osmosis and remineralisation. We recommend that you have your water professionally tested to determine if this applies to your situation.
The options for these areas are:

  1. Filtered rainwater (if you have a tank). Ensure that the water is sanitary and use basic sediment and carbon filtration- as offered by most filters
  2. Use bottled water with low hardness (Ca and Mg), TDS and Chloride ion concentrations. The company selling the water should have specifications/readings they can give you
  3. Reverse osmosis with remineralisation.

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