"Raising your expectations for over 20 years"


Product added to basket

The Importance of Using the Correct Grade of Purified Water in Autoclaves

Category: Autoclaves

Autoclaves are expensive pieces of equipment. Failure to use purified water that does not have a written specification can cause irreparable damage.

When considering which grade of purified water to use, it is important to know what happens if you use poor quality purified water in your autoclave. Contaminants such as lime can deposit in the internal pipe work of the autoclave and actually block it. Lime scale is easily dealt with by using a mild acid, as you would do at home with your kettle.

The lime scale will dissolve when in contact with acid. Silicone on the other hand, can deposit at the high autoclave temperatures, and this is not so easy to deal with. To remove silicone you would have to use a hammer and chisel, which is not practical.

Water purity is measured in terms of its electrical conductivity. If water is pure it conducts electricity well, if on the other hand it is contaminated, then it does not conduct electricity well. Water conductivity is measured in Micro Siemens (VS).

To avoid damaging your autoclave, you will need to use purified water that has a written specification, stating that conductivity is 5 micro Siemens per cm (5pS/cm) or less.

To put this into perspective, the chart below explains the relative conductivity of different common waters.


gS/cm (Conductivitv)

Totally Pure Water


Distilled Water


Domestic Tap Water


Sea Water


The purified water from Medical World Limited does have a written specification, which is 2.5 pS/cm @ 20% C or lower. However, the measurement is typically less than I .0pS/cm @ 20%C.Every day health professionals buy water that has been sold for use in their autoclave that is just not suitable. Labelling can sometimes give the game away. For instance if a product is called medical water or autoclave water it should be viewed with extreme caution. The water for autoclaves is either distilled water which is expensive or purified water. Before you buy water for your autoclave, insist on a written specification. If the supplier has not got one, do not buy it.

Committed to you


Click the Knowledge bank button on the home page to access various articles and videos. Alternatively ring 0121 580 6600. Our knowledge bank team have a wealth of experience.


If you are having difficulty finding the products you need, Our experienced purchasing team will do that job for you


If you can find a product cheaper elsewhere, call us with the details and most times we will either match or better the price.


Your Medical World credit account will give you up to 60 days credit.

Did you know?
You can also set up a Standing Order online using your Credit Account (Credit Account holders only).

Taking the stress and hassle out of repeat ordering. (Find this feature by clicking 'Your Account' and then selecting Standing Orders)

Follow Us