Is using distilled water absolutely necessary in the APO?

I recently ordered the Precision Oven. The manual notes that “Distilled water is recommended to minimize scale buildup and maintain correct operating function.” I understand the purpose, but seems like a lot of trouble and expense to make at home and I don’t want to buy plastic bottles of it.

So, my question: Considering that I don’t live in a hard-water area, is it advisable to just use tap water and follow a routine of descaling/cleaning periodically, or is it a must to use distilled water?

If I do use tap water and still descale regularly, will I nonetheless shorten the life of my oven?


Hey Bud, welcome to your Anova users’ Community forum.

If it rains in your area it might be only a small amount of trouble to collect rainwater in a glass or stainless steel vessel. It’s free and pure enough. If it’s not too much trouble pass the collected water through an inexpensive paper coffee filter before using. That’s what i have been doing for many years.

I am not familiar with the steam generating parts of the APO to know if using a descaling chemical solution will shorten your oven’s life. If the manufacturer recommends it that sounds like it’s mandatory to me.

Not descaling will eventually eliminate your oven’s steam mode from your cooking choices.

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Rainwater is an interesting solution, thank you. And I clarified my comment about descaling.

Thanks again!

I was wondering whether something like this could be used:-

Or whether we should buy bottles of distilled water. Here in the UK were are talking about £13 for 5l. Depending on how much water I need to buy in a year the machine might be cost effective.


Hey budparr - I use distilled or demineralised water for the ironing as well so I’m always buying it. If you look around you should be able to find it for a reasonable price. Look for 5L or larger to get the best price.
Tap water & a descale cycle is still perfectly fine but I feel the best way to prolong the life of my equipment is to avoid the scale build-up altogether.
If you do have access to rainwater you should still try to get it tested. Depending on your local air pollution and water capture method it might not be as clean as you think.

All the best!