Water filter time-based expiration?

[Julian]

I have a couple of Britta water filtering devices, one is a jug and the other a kettle. They both take the same carbon filters but the jug has a fancier expiration meter that measures actual water flow through the filter and I believe considers the filter at 0% capacity (as in needs replacing) after it has filtered 150L whereas on my kettle the expiration meter is a simple timer that counts down a number of days until it declares the filter expended. Based on the web site info I found via google (https://store.brita.com.au/blogs/news/h ... ter-filter) it says "As filtered water consumption is increasing, as a general rule we recommend replacing your MAXTRA+ filter every 4 weeks or 150 litres of water usage" so I suspect that count down is 4 weeks since the Britta advice quotes that as the average time for a family to use 150L of filtered water (an Australian family because it's from the .au web site but I assume that's a reasonable rule of thumb for us folks in the UK as well).

My question is, when one considers the chemistry, is the lifetime of the filter genuinely only governed by the amount of water that has flowed through it or can the filters time-expire (as in die of old age) even if hardly any water flows through them? I ask because I use my kettle extremely rarely, maybe three or four big mugs of tea a month, so even replacing the filter once a year would probably be replacing a filter that had filtered only 20L of water at most.

Right now I'm simply ignoring the expiration timer on my kettle and have been doing so for the last 8 months or so since I bought it but I'm wondering if, despite having filtered very little water, my filter might be expiring or have expired for other time-related reasons.

- Julian

[UncleEbenezer]

What role does the filter serve, and why does it matter if it expires? Is your water source contaminated?

[9873210]

You also need to consider biology. There is some concern that after long use filters become breeding grounds for microbes: a large surface areas with all the chlorine removed.


https://pubmed.ncbi.nlm.nih.gov/8740859/

[kempiejon]

My chum has an inline Brita filter on a separate tap in his kitchen sink, he knows when it's due to be changed when the cat leaves its drinking water in the bowl and uses puddles. The cat's water is sourced from the Brita tap.

[Julian]

What role does the filter serve, and why does it matter if it expires? Is your water source contaminated?

A fair question. Only I am able to answer here and my answer is no, my water is not contaminated, but were my kitchen appliances able to post on this site they would probably answer yes.

The role my filter serves is to stop me having to replace broken coffee makers about once every 12-18 months, or throw out kettles every few years simply because they are getting too grungy despite fairly regular descaling on both devices. I have very hard water that really messes up my appliances (except, curiously, my washing machine and dish washer which tend to last at least a decade). Descaling keeps limescale somewhat at bay but it's a hassle and with things like the coffee machine I also hate the energy waste of, in order to flush out any remnants of the de-scaler I just used, having to then boil multiple pots of water through the machine only to then pour them down the sink. A friend suggested I do what she does which is to only fill the appliances from a filter jug so that's what I am now doing. For drinking water I am perfectly happy with tap water, in fact I can't really tell the difference between that and the filtered water, but my research before buying did indicate that the minerals that the filters remove does significantly reduce limescale build up. So far so good, after just over a year my kettle still looks factory-fresh and my coffee machine hasn't broken but it's relatively early days still.

You also need to consider biology. There is some concern that after long use filters become breeding grounds for microbes: a large surface areas with all the chlorine removed.

https://pubmed.ncbi.nlm.nih.gov/8740859/

Yikes! Thanks for that. The filter at most danger is the one in my kettle, the one in the jug I use to fill my coffee machine gets sufficient water flow that it is at least replaced every few weeks so less of a breeding ground than the kettle filter where I was considering, at the extreme, replacing it only once a year. That now seems a pretty bad idea although I suppose one mitigating factor is that if it does end up contaminating the water that water is by definition about to be boiled since it's going into the kettle which I assume (perhaps wrongly?) would kill microbial contaminants but even so...

In retrospect maybe buying the kettle with integrated filter was ill-advised for my low use case. Probably just one of many examples of me going a bit stir crazy during the initial lockdown and buying all sorts of stuff on Amazon that I didn't really need. The answer seems pretty simple. Luckily the filter holder in the kettle is a plastic insert that rests in the top of the kettle and can be simply lifted out to turn the appliance into a perfectly good looking normal kettle that I can then fill, when needed, with water from my filtered water jug. As well as maintaining the practice of only using filtered water in the kettle to keep down limescale build-up that would also very marginally increase the daily flow rate through the filter in my main jug thus reducing the amount of time between filter changes with the subsequent biological issues.

- Julian

[DrFfybes]

I have a couple of Britta water filtering devices, one is a jug and the other a kettle. They both take the same carbon filters

...

I have very hard water that really messes up my appliances

If you are filtering for limescale, there are much cheaper filters than the carbon ones. In our place there is an inline filter on the incoming main. It was a carbon one, did showers, washing machine, everything. I reckon the £30 cartridge was dead after about a week. I swapped it for a scale filter, which was 1/3 of the price and seems to last about a month before getting gritty. It has a bypass valve, which I tend to use these days.. One day I'll replumb so it only filters the downstairs tap.

You can tell when they need changing as your tea is gritty in the bottom.

Paul

[UncleEbenezer]

What role does the filter serve, and why does it matter if it expires? Is your water source contaminated?

A fair question. Only I am able to answer here and my answer is no, my water is not contaminated, but were my kitchen appliances able to post on this site they would probably answer yes.

- Julian

Heh. The joys of hard water! But how does a filter actually work there? Surely the scaling is dissolved calcium, and you'd deal with that much better with a drop of something acidic (to keep it dissolved) than a filter?


My kettle and espresso machine both date back to late last century, and get used daily (the kettle much more than just daily). They get plain tap water (no filtering), and neither has ever needed descaling. Soft water

The one curiosity is the gradual appearance of a green colour in the espresso machine's water tank.

[Dod101]

My son lives on the County Antrim Coast and the first time I visited him there I could not understand why my stomach was doing somersaults. Then it dawned on that it must be the lime. Their village is built on limestone. Checked with the website for the water authority and there is a huge amount of calcium carbonate and I think magnesium. I told them about this and they got a water filter which changed things dramatically. I live near the Highland Spring bottling plant and get it out of my taps.

Dod

[DrFfybes]

I live near the Highland Spring bottling plant and get it out of my taps.

Dod

That must be one hell of a bottle you have outside your house

[9873210]

In retrospect maybe buying the kettle with integrated filter was ill-advised for my low use case.

If I were boiling water less than once a week I would use a microwave or hob, washing and drying the pot after each use. That deals with microbes, and limescale, and reclaims a few dm^2 of counter or dm^3 of cupboard. Perhaps it's time to e-bay or re-gift the kettle?

In food prep I try to stay in what I'd consider to be the mainstream. Some outliers will be perfectly safe, but few people are studying them so you get to be your own lab rat.

Millions of people leave wet kettles for a few days. If that's a big problem somebody would notice. Leaving a wet kettle idle for many weeks is probably safe, but it is unusual so who knows?