If our tap water is safe, why does my water filter turn brown after 3 months?
That's because the water filter manufacturers want you to continue to buy their products (which is not useful). The water filters are designed to discolour after continuous 3 months of use. If you change the filter after just one week, you will see very little discolouration.
To test this hypothesis (your water filter) you should set up a tap with a filter, through which you should run only PURE DISTILLED water (NOT Mineral Water - those have minerals!). After 3 months of running distilled water through the filter, see if there is discolouration. If the filter is really filtering out things in the water, the filter should still be clean. If the filter is discoloured, then you know the filter manufacturer is cheating you - if even distilled water discolours the filter, then it is obviously not an issue with the water. BUT... there are some stories that suggests that bottled water in many cases are simply tap water. So there is that to worry about.
After the above test, if you are still inclined, you can re-run the test (new filter) but this time with Mineral water. After three months, check the filter. If the discolouration is LESS than that of the filter for PUB water, you can probably conclude that Mineral Water has LESS non-water elements (contaminants) in it. If the Mineral Water filer is AS Discoloured as tap water filter, it means that your Tap Water has as much mineral as bottled Mineral Water. (Which means you should NOT buy mineral water if you are going to filter out the minerals in your tap water). If it is MORE discoloured than the tap water, then you are really getting your money's worth from Mineral water. There are MORE minerals in your mineral water than in tap water BUT... why filter out the minerals in tap water? Think of it as a supplement to your mineral water.
BUT... the greater danger is not the slight minerals (copper, iron) that might be in your tap water. The greater unknown danger is phthalates (google that). And a simple filter will not filter out phthalates if it is present in tap water. You will need a nano-filter (google that) to effectively filter out phthalates.
Speaking of phthalates, the bottled water in the experiments suggested above (whether distilled or mineral) should NOT have phthalates. But they may have BPA or other chemical contaminants. Which may thrown off your results.
The problem is that Water is a universal solvent. It will dissolve ANYTHING. And carry it along. Until you drink it.[Note: This online comment is either a troll or being sarcastic. The ket giveaway is the 2nd last paragraph.
Anyway, good luck with the experiments, if you are keen to try it. I started estimating the cost and stopped after my estimates reached $3000. I can't even afford a water filter system. So no question about affording to run a $3000+ experiment just to find the right filter that is not trying to cheat me.
So now I drink straight from the tap (boiling water is also a waste of resources), and consider it my mystery mineral water.
At least I don't live in Flint, Michigan (google that).
The question was from the comments on a story about the safety of our tap water. PUB said it was safe to drink.
There were some sceptic as to PUB's assertions.
But worries about the safety of our tap water were unrealistic. One comment was that a filter would be discoloured after the recommended use. After establishing that he changed his filer once a year and he estimates that about 5000 litres would have flowed through the filter, this was the response:]
Well, using your base figure of 5000 litres, don't you think that running 5000 litres of water through a filter would result in some discolouration? PUB reports that there are on average 161 mg of dissolved solids per litre of water. Most of these dissolved solids are sulphates, Calcium, chloride and chlorine. Please note the unit of measure - some are in mg, some are in ug (microgram). At 1000 l, there could be on average 0.161 g of solid on your filter. At 5000 l, the total dissolved solids in your filter (assuming it catches all non-water elements) would be... 0.8 g.
Another way of looking at it is, for you to ingest that amount of dissolved solids (0.8g) that is indicated by the discoloured filter, you will need to drink 5000 l of water.
Compare that with the poisoned residents of Flint Michigan (google that).
I think you should be (slightly) worried if your filter gets discoloured say within a week or less. 3 months and above, the water would be considered safe and even more than safe.
Here's another thought: If you pour yourself a glass of filtered water, took a sip and then place it beside you while you check your emails, file your income tax, etc. then an hour or so later, you took another sip, is the water as clean?
Because even with good air (PSI of less than 50) there may be as much as 100 ug of particulates per cubic metre of air. Some of that may settle on your glass of water. And then you drink it.
Of course you would be right to say that the amount of dust settling on your glass of water is insignificant. And you would be right.
It's through breathing that those contaminants are entering your body. On average, a person sucks in 11,000 litres of air per day. With good PSI, there would be about 100 ug of particulates per 1000 litres. In a day you would have breathed in over 1 mg of dust.
In a year about 400 mg. That would be more than the dissolved solids you drink - assuming you drink 2 litres of water a day, and only water, in a year, you would drink 730 l of water (not 5000 l)., and ingest about 110 mg of dissolved solids. Or about 1/4 of the pollutants you would breathe in in a year, with Good Air Quality (less than PSI of 50).
The point is, you're worrying about the wrong pollution. You should wear an N95 mask at all times.
Note: PUB figures for average daily consumption of water per person is about 150 litres of water per day. But this is water for everything - drinking, bathing, cooking, laundry, etc. That's about 55000 l per person per year. However if the filtered faucet is in the kitchen for drinking and maybe cooking, 5000l for a year would cover 4 to 6 persons.