So I recently got myself a Brita water filter jug and I've got a query for anyone who owns one.

Brita recommends you change the filter approximately every four weeks. I assume this is based on daily use, so perhaps filling the jug twice a day (or thereabouts)? I personally only fill it every 2 - 3 days as I'm only using it in a coffee machine as opposed to drinking water from it daily.

Therefore, I'm assuming I could probably get away with changing the filter every 8 weeks rather than the usual 4.

From those that own one, would you say that's accurate? Or do you think I'd be leaving it too long?

I'd contact Brita, but I assume they'd tell me to change it sooner rather than later because it'll make them more money. (I'm such a cynic.)

I have one and must admit I don't change it as often as they say to. Mainly because I live on my own so don't use as much water as a family would do.
I think I used my last one for four or five months, I can't really remember. I wish they stated how many litres it could filter per cartridge, rather than a length of time, then we might be able to work it out.

My boyfriend tells me when the cartridge needs changing in ours, he says he can taste the difference in the water! I can't!
We must change ours every couple of months, and it's used daily.

I tend to run mine over for a few weeks as I'm on my own too and fill it up occasionally.

One day I'll make a cup of tea with tap and filtered water and see if I notice.

Thanks for the replies, people. I'll leave it for a while longer then!

It all depends on how hard your water is.
I know when mine needs changing without looking at the LCD timer in that when making a cup of tea you start to notice scummy bits when brewing the tea bag.

I was just reading this thread out of interest, as I invested in a non-proprietary in-line water filter system, as an alternative to the water jug method you are all using, and I also guess when to change the cartridge.

Mine says 6 months or 2,500 litres, and in 5 years of use I have realised that the best time to change it is when the kettle limescale filter starts to aquire sediments on the plastic mesh. Also after a certain time the activated carbon that carries out the bulk of the filtering becomes ineffective and the accumulated sediments may be harmful, although there isn't enough evidence to prove this beyond doubt.

Anyway I digress. Brita do state the litre volume before replacement for all their filters and if you scroll down this Amazon page just beyond halfway you can find out what yours is: http://www.amazon.co.uk/gp/product/B...=sr_1_1&sr=8-1.

Thanks for that evil c. According to that mine does 100 litres. I would think that would do me for about 3 months or maybe a bit more then. I only use it for drinking water straight and I have the fridge door jug with a Maxtra cartridge. Hot drinks I just use tap water in the kettle.

For info the 6 month/2,500 litre granular activated carbon (GAC) cartridges I use cost about £9 each. It's changed undersink via push-fit 1/4" connectors and I fitted the last one on 23rd March 2015 which is still going strong today. Other carts are available for around the same price that have the capacity to filter 6,000 litres, albeit with the same 6 months nominal effectiveness deadline.

My in-line filter system is an undersink one with a mixer tap above roughly similar in looks to this one (although I only paid £29 for mine from B&Q 5 years ago, however they don't sell it any more): http://www.waterfilterman.co.uk/taps...282120051.html.

So (I've been starting sentences with 'so' since I found out it winds a lot of FMs up) my mixer tap works just like a normal mixer except when I want filtered cold water I select the little tap at the bottom letting it run cold before I take any water.

I looked at all the various ways of filtering water in some depth before choosing. The long term cost was the most important factor. I thought the Brita products were extremely expensive for what you get and no more effective than the in-line method that (for me) is a lot cheaper.

The hardest bit was trying to find out the intricacies of exactly how the filters filtered out what they were supposed to do, and what the filters were, as the manufacturers' data sheets try to blind you with science, and dodgy science at that in some cases.

My filter carts work on the same adsorption principle (pollutant molecules in the fluid to be treated are trapped inside the pore structure of the carbon substrate) as the fridge ones and Brita i.e. granulated activated carbon (GAC) filtration. Although Brita's filtration system is patented I can't find any data that shows it is more effective than the carts I use.

Activated carbon filter is produced by super-heating dried coconut husks in a low oxygen environment, using a process called pyrolysis. The resulting "biochar" husk is a purified form of carbon containing large amounts of cellular sized surface area, negatively charged to attract positively charged toxins.

Toxins in the water become attached to the husk's carbon surfaces and over time, the attractive charge of carbon surfaces are neutralized, making it time to change the filter.

Odd that they say the maxtra cartridge has a volume of 100 litres, lasting approx 1 month. That implies most people use around 3.3 litres of drinking water a day, which seems pretty high to me?

Although perhaps it's based on families where multiple people will use the same jug.

Only I use mine and I don't use it every day, so it seems the filter will last a good while.

This is the point, really. I live in a very hard water area and we certainly never got anywhere near the expected level.

Because the hard water was having such a detrimental effect on our appliances as well we ended up going the full hog and getting a block salt water softener.

They aren't cheap but for us it was worth it.