Water & water treatment
Water & water treatment for your autoclave
Which water your autoclave really needs — and how to put an end to the tiresome lugging of canisters once and for all.
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In short
Only demineralised water (deionised/lab-grade water, max. 5 µS/cm) — no tap water or battery water. A water treatment unit such as AQUAdem 40 supplies it automatically, without canisters.
The right water, less effort
Which water does my autoclave need?
Water quality determines every load — and the lifespan of your device. Use exclusively demineralised water (deionised water, lab-grade water class 2–3) with a conductivity of max. 5 µS/cm. No tap water, no battery water — both leave limescale and silicate deposits.
„Poor water quality“ — despite fresh water?
This warning almost never indicates a fault. Usually the conductivity is too high (wrong water) or there is a limescale build-up in the tank. With the right water source the message normally disappears immediately.
An end to lugging canisters
Anyone reprocessing daily does not want to keep buying and carrying water. A water treatment unit such as AQUAdem 40 produces the right water directly from the mains supply — fully automatically, without canisters. From a single fill you typically get several cycles.
- Consistent water quality = stable, documentable loads.
- Protects the chamber, valves and seals — less wear.
- Already have a water treatment unit? It can usually be kept in use (note the pressure reducer).
You don't have to handle this on your own
The most common concerns of our customers — and how we solve them.
„A warning despite fresh water — is the device broken?“
Almost never. Usually it's only the conductivity that's off — with the right water source the message disappears.
„Constantly lugging water?“
AQUAdem produces the right water directly from the mains — no more canisters.
Lugging water is a thing of the past.
The right water quality determines every load. AQUAdem supplies it automatically — without canisters.
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Frequently Asked Questions
Water & water treatment – key questions answered clearly.
Which water must I use for my autoclave?
Use exclusively demineralised or fully deionised water (deionised/lab-grade water) or distilled water. The conductivity should be as low as possible – ideally below 5 µS/cm. Tap water is not suitable and can damage the device.
May I use tap water in the autoclave?
No. Tap water contains limescale, minerals and salts that leave limescale and silicate deposits in the chamber, valves and seals. This affects every load and shortens the lifespan of the device. Use only demineralised or distilled water.
Is battery water or iron water suitable for the autoclave?
No, technical battery or iron water is not suitable. It can contain additives that damage the device. Use demineralised/fully deionised or commercially available distilled water.
Which conductivity should the water have?
A conductivity of no more than 5 µS/cm is recommended. The lower the conductivity, the better for stable, documentable loads and the gentler it is on the device.
What does the message „Poor water quality“ mean?
This warning almost never indicates a fault. Usually the conductivity of the water is too high (wrong water), the water has stood in the tank too long, or there is a limescale build-up or a fouled sensor. With fresh, suitable water the message normally disappears immediately.
The message „poor water quality“ appears despite fresh distilled water – what should I do?
Even fresh water can trigger the message if the sensor is fouled or the water has stood in the tank too long. Empty and clean the tank, then refill with fresh water from a new canister. If the message persists, please contact our service team via steri24.de/help.
Do I still need distilled water with the AQUAdem 40?
No. The AQUAdem 40 is installed between the mains water connection and the autoclave and automatically converts tap water into demineralised water. The autoclave refills itself – you no longer have to buy or lug distilled water.
How does the AQUAdem 40 work?
The AQUAdem 40 is a power-free ion exchanger with a mixed-bed resin filter that produces the right demineralised water directly from the mains supply – fully automatically and without canisters. From a single fill you typically get several cycles.
Does the autoclave need a fixed water connection?
No, a fixed water connection is not required. All our autoclaves are stand-alone devices with an integrated fresh-water and waste-water tank and can be filled manually with distilled or demineralised water. A fixed water connection is available as an option and can also be retrofitted later.
Can I fill the autoclave manually even when a water treatment unit is connected?
Yes. With the fixed-water-connection option both modes of operation are possible: stand-alone with manual filling or automatic refilling. This can be activated or deactivated at any time.
Is the AQUAdem 40 water treatment unit worthwhile when buying a new autoclave?
Yes, especially with daily reprocessing. It saves time and costs in the long run because there is no need to keep buying and lugging distilled water. A fixed water connection is required; let our configurator or our advisors put together the right variant for you.
What do I need to order to operate the autoclave via a fixed water connection?
Order the „with fixed water connection“ option on the device plus a water treatment unit such as the AQUAdem 40. All autoclaves can still be filled manually as well.
Can the fixed water connection be retrofitted later?
Yes. The fixed water connection is optional and can also be retrofitted afterwards if the need increases later. Contact us for a suitable retrofit kit.
Can I keep using my existing water treatment unit?
As a rule yes, since the fixed water connection is largely standardised. Please note that a pressure reducer is usually required; connecting a third-party system is at your own risk. The AQUAdem 40 is recommended. If in doubt, our service team will be glad to advise you.
Which hose size or which water connection is needed for the fixed water connection?
As a rule a 6 mm hose connection (4 mm on some models). For a direct drinking-water connection a 3/4-inch thread with an interposed water treatment unit is used. Pay attention to the permissible pressure range and a pressure reducer.
How do I connect an external water treatment unit such as the AQUAdem to the autoclave?
The connection is made via the fixed water connection on the autoclave (the „Fresh Water“/„Waste Water“ connections on the rear). The water treatment unit is placed between the water source and the autoclave. Details are given in the respective manual.
How far may the water source be from the AQUAdem 40?
For the fixed water connection the line to the water source should not be too long – plan for a short distance (in practice up to about 3 m). This keeps the automatic filling reliable.
How much water does the autoclave use per cycle?
Water consumption depends on the device volume and the selected programme. With one tank fill or one AQUAdem fill you typically achieve several cycles. Exact figures can be found in the manual of the respective model.
How high should I fill the fresh-water tank?
Fill the fresh-water tank at least until the warning message disappears, and at most to about 1 cm below the rim. Do not overfill the tank, to avoid overflowing.
Do I have to completely change the fresh water regularly?
The used water automatically ends up in the waste-water tank, which you empty once it is full. The fresh water does not have to be completely changed regularly – you only top it up. However, if the water has stood for a very long time, replace it with fresh water.
Can I reuse distilled water?
Reuse is generally possible with a filter, but we recommend fresh water, as stale water starts to smell and degrades the water quality. With a water treatment unit you produce fresh water directly from the mains supply whenever needed.
Can I produce distilled water myself?
Yes. With a water still or the AQUAdem 40 you produce suitable distilled or demineralised water yourself from tap water. This saves you from buying canisters.
What water quality does a water still deliver?
A water still delivers water with low conductivity that is suitable for the autoclave. Please note: such a device is not designed for drinking water or medical applications.
What is the difference between a reverse osmosis system and the AQUAdem 40?
A reverse osmosis system (RO) works with membrane, carbon and resin filters, requires power and produces very pure water. The AQUAdem 40 is a power-free ion exchanger with a mixed-bed resin filter – cheaper and, for most autoclaves, the more practical choice. We are happy to clarify which solution suits you in a consultation.
How often do the filters/cartridges of the water treatment unit need to be changed?
The replacement intervals depend on the water hardness and the number of cycles. Replace the mixed-bed resin cartridge or the bacterial filter on time according to the manufacturer's specifications so that the water quality remains stable. If the water quality declines, the filter is usually exhausted.
How do I tell that the filter of the water treatment unit is exhausted?
A typical sign is the message „Poor water quality“ despite a connected treatment unit, because the rising conductivity is no longer sufficiently reduced. In that case, replace the cartridge or the filter.
Does the autoclave have a built-in water quality sensor?
Yes. Our autoclaves have a built-in sensor that measures the conductivity of the water in microsiemens per centimetre. This continuously monitors the water quality; a warning appears if needed.
Do I need a separate conductivity meter?
A sensor that measures the conductivity of the water is already built into the autoclave and thermal disinfector. A separate measuring device is therefore usually not required.
What does the KRINKO say about water quality in instrument reprocessing?
The KRINKO requires that the microbiological and chemical requirements for the water be defined for the respective process. For the final rinse in the thermal disinfector, deionised water is recommended to avoid deposits and crystal formation on the instruments.
Why does the KRINKO recommend deionised water for the final rinse?
Deionised water (fully deionised water) is recommended to avoid deposits or crystal formation on the medical device. At the same time, microbiologically impeccable water must be ensured, which can be provided, for example, via suitable water filters.
Which water does a thermal disinfector (washer-disinfector) need?
Drinking water can be used for cleaning depending on the programme, while deionised water is recommended for the final rinse to avoid deposits. The exact requirements depend on the process and should be defined as part of the validation.
Does the required water quality depend on the type of instrument?
Yes. For instruments with particularly high reprocessing requirements – for example, long, narrow lumens with endotoxin or particle freedom – a higher water quality may be necessary. For steam sterilisation in the autoclave, demineralised water with low conductivity is decisive.
What happens with water that is too hard in the autoclave?
Water that is too hard and high in lime leaves limescale and silicate deposits in the chamber, valves and seals. This increases wear, can trigger error messages and shorten the service life. Therefore use only demineralised or distilled water.
How does the right water quality protect my device?
Consistently low conductivity prevents limescale and salt deposits, protects the chamber, valves and seals and ensures less wear. The result is stable, documentable loads and a longer lifespan.
Where do I fill in the fresh water?
You fill the fresh water in at the top into the fresh-water tank, on many models under a flap on the top of the device. Viewed from the front, the fresh-water tank is usually on the right and the waste-water tank on the left.
What does the message „Feed water empty“ mean?
This message indicates that there is too little fresh water in the tank. Top up with distilled or demineralised water. If the message persists despite a filled tank, please contact our support via steri24.de/help.
The cycle was aborted due to too little water – what now?
Top up the fresh-water tank with distilled water and restart the cycle. With automatic filling, check the supply line. If the abort continues to occur, please contact the service team via steri24.de/help.
What is needed for water drainage, and may the waste water go into the sink?
Fit the supplied hose to the rear of the device and lead it into a container (e.g. an empty canister), a drain or the sink. A fixed waste-water connection is not required.
Do I need a waste-water connection at the installation site?
No. Thanks to the integrated waste-water tank, no fixed waste-water connection is required. The waste-water hose can be led into a container or an existing drain.
How hot is the waste water coming out of the autoclave?
The used water is only slightly warm. Many customers simply collect it in an empty canister, such as the one from the distilled water.
When opening the door, water runs out of the chamber – why is that?
This is usually because the end of the waste-water hose touches water and sucks water back after drying. Make sure the end of the hose does not lie in water and can drain off freely.
How do I drain the dirty water?
The dirty water is drained via the „Waste Water“ hose connection. Make sure the hose engages correctly and is not kinked. If the message „Drain dirty water“ persists after emptying, switch the device off and on again.
What are the two tanks, fresh water and waste water, for?
The fresh-water tank holds the demineralised operating water used for the sterilisation steam. The used water then flows into the waste-water tank, which you empty as needed. This keeps clean and used water separate.
Is one canister enough for the waste water of the 3-litre autoclave?
Yes. With the compact 3-litre device, a canister or a nearby drain is sufficient; you do not need a water connection. You fill distilled water in at the top, and the waste water runs into the canister or drain.
Is there a pump to pump the waste water upwards?
We do not offer a dirty-water pump for higher-level lines. The devices have a waste-water tank that is emptied via a hose into a lower-lying container or drain.
How do I activate the automatic water supply?
The automatic filling can be activated in the device menu via the water-supply/fill-water setting, provided a fixed water connection with a water treatment unit is present. The exact menu path is given in the manual; our service team is happy to help with questions.
Do I have to top up water immediately when the refill warning appears?
You do not have to react immediately, but you should top up the fresh-water tank promptly with distilled or demineralised water so that the next cycle starts without interruption. A running cycle is usually still completed.
How do I regularly check the water and steam quality?
The water and steam quality should be checked regularly. For this, our autoclaves have a built-in water quality sensor that continuously monitors the conductivity and warns of deviations.
Can I use water from the supermarket or DIY store?
Commercially available distilled water from a drugstore, supermarket or DIY store is generally suitable, as long as it is not labelled as technical battery/iron water. Pay attention to a low conductivity.
Which water solution suits my autoclave?
That depends on your device volume and how frequently you use it: for infrequent use, manual filling with distilled water is sufficient; for daily operation, the AQUAdem 40 with a fixed water connection is worthwhile. You will find the right combination in the autoclave configurator or through our advisory service.