Comment by ourmandave
20 days ago
Does filtering your water with a whole house filter take the fluoride out?
Because I live in a small township that delivers well water to you tap. It tastes horrible, shortens the life of pipes and appliances, and smells like sulfur.
Every year they mail a flyer that explains how the lead levels are dangerously above the national standard and you should run the tap before you drink from it.
Like, sorry there's nothing we can do about it. =(
> Because I live in a small township that delivers well water to you tap. It tastes horrible, shortens the life of pipes and appliances, and smells like sulfur.
Oh man, I used to live in a place like this. You could smell if a restaurant served filtered water (lots filter for the soda machine, to keep mineralization in it down I assume, and use the same water to serve) or straight from the tap, without taking a drink. Like with your nose six inches above the cup, you could smell it. Luckily, almost all served filtered.
I looked in to this recently.
Turns out that carbon filters do filter fluoride, but only on the first few X litres of water, where X is in the first 0.01% or so of their expected lifespan. So, they do, but not really usefully in any sense.
My filter that I wanted to know about (so that my kid is getting fluoride) is a 2-stage filter, with the other stage being a particle filter, but fluoride is very small and unaffected.
Your filter might be different of course.
FWIW, in my city, the water has essentially zero fluoride if it isn't added, and it has been a great intervention.
If it's reverse osmosis based, yes. If it's some other kind of filter, likely no, and you should buy a TDS meter and use it, because in all likelihood it's not really filtering anything. I did exactly this. It turned out that my carbon based filter had more TDS than completely unfiltered water from a tap in the garden. RO water, even re-mineralized, had 1/15th the TDS IIRC.
TDS is just Total Dissolved Solids. What solids though you don't know and you could be adding carbon while removing others which is likely the case.
Also those dinky little TDS meters don't even measure TDS. They measure electrical conductivity and with a little math they use the EC as a proxy for TDS. It's typically only calibrated to one specific ion, others will be off by some factor. Also keep in mind TDS is expressed in PPM as CaCO3.
Yes, but be that as it may, at least it shows whether _any_ filtering is occurring at all. Which in the case of even a somewhat spent carbon filter is not a thing. RO does the job so well, you have to remineralize afterwards or the water doesn't taste like anything. You could literally pee into a jar and get fresh water on the other end. That's sort of what happens on sailing vessels that are equipped with water makers - they simply run sea water through RO.
If thats your water quality, worrying about flouride seems misplaced.