Is there a household method to decolorize potentially contaminated water?

Question

I am living in my dorms at the moment and apparently it is an accepted thing that the water in the building is brown and yellow. According to my RA, this is a characteristic of the town I live in.

The only "clean" water we get is a water filter at the zeroth floor of our building where transparent water comes out.

Other than that the water that comes out of the tap, the kitchen, the shower, and the toilet bowl is light yellowish-brown water. I haven't done enough research as the cause of this problem.

Boiling water doesn't seem to change the colour either (is this even possible?). I for one cannot live like this, so I am asking the community here if they know a household method to remove the discoloration from the water.

Answer 1

A simple test you can do is to boil a large amount of the water and see if a sediment is left in the vessel. This will tell you certain things about you contaminant.

• Is it particulate? We expect so because a filter is removing the contaminant.
• Is it's boiling point below that of water?

If you get a residue what is it's state? I'm expecting a solid, I dont anticipate a coloured liquid that is miscible in water with a boiling point higher than water.

• Does it burn? How does it burn? Colour of flame? Further residue?

I'd also try adding a colourless surfactant to the water, does it remain coloured?

Answer 2

I believe, there are two possible options, that are not immediately harmful for a drinker

• fine rust particles in water. I suspect it is not your case, but if it is, fine mechanical filter should do the job. To check, add rust-removing chemicals, such as oxalic or citric acid, to warm colored water. If the coloration will vanish, you probably can remove the rust with fine mechanical filter (beware, I have absolutely no idea how fine the filter may be in your case). The reason is bad condition of water pipe system and should be dealt with accordingly.

• organic compounds, most likely tannin contamination, is very possible if your water source is swamp-fed. The contamination may be very durable, and, honestly, even being natural for local water, still may be harmful. To check, find bleaching agent based on any hypochlorite, and see if it will destroy/change the coloration. If it will, most likely the source is organic and may be slightly harmful if used for drinking for a long time.

There should be also some government subdivision, concerned with water quality regulation. I believe, you will find more information if consult with them.

Answer 3

My guess would be that the yellow-brown color in your tapwater is mainly caused by small suspended particles of rust (i.e. hydrated iron(III) oxides) from old iron pipes.

Even in places with well-maintained plumbing and good drinking water, such rust contamination can often appear temporarily after maintenance work or some other interruption in the water supply dislodges built-up rust deposits from the pipes. If you're getting rusty water all the time, it suggests either that the water distribution network in your building / town is in pretty poor shape, and/or that the raw water supply used to produce your tapwater is already quite rich in dissolved iron, which will precipitate out into rust when the water is aerated and chlorinated at the water processing plant.

Alas, I can't think of any simple "household chemistry" method to get rid of the rust suspension in a way that would be practical for drinking water.

• In theory, if you simply filled a large plastic container with the rusty water and let it sit long enough, the rust should settle to the bottom. However, if the particles are very fine (and they likely are), that may take a long time. You could speed the process up with a centrifuge, but that takes it way out of the "easy and practical" range.

• If you just wanted to get rid of the visible coloration, you could add a chelating agent like citric acid, polyphosphate or EDTA to dissolve the rust. However, this will leave you with a solution of e.g. ferric citrate, which, while indeed drinkable in principle, may not quite have the neutral flavor you'd expect of clean water. (This could still be worth a try, if only to check if the color is indeed caused by rust; citric acid can be found in many stores, both as a food additive and as "biodegradable rust / scale remover". Do make sure it's pure, if you intend to drink the result, and don't overuse it.)

• The most practical solution may simply be to get your own water filter. You'll want to get one that's suitable for removing rust particles, or whatever it is that's actually coloring your water. If this is indeed a common problem in your town, a local home improvement store can likely recommend a suitable filter system for you.