OK, at the risk of reintroducing a topic that has already been debated to death....

Most posters seem to agree that tap water in CM isn't potable without treatment, but there doesn't seem to be any consensus on WHY this is the case.

Is UV treatment by itself enough (ie: to kill pathogenic organisms), or are there chemical and/or metallic contaminants as well? We have consumed tap water in northern India using only a steripen for treatment with no (apparent) problems, and would be more than happy to do that in CM if bacteriological/viriological/parasitic contamination was the only issue.

Anyone have any actual water test results of CM tapwater to illuminate exactly WHAT is wrong with drinking it?

Thanks!

Rob.

Sometimes there is a lot of chlorine in it.

You can really smell it.

Depending on where you live your tap water is either from a dam or artesian well.

If the latter, a ~40m bore will produce potable water which really only requires simple 3 stage filtering although a large sediment pre-filter may be desired.

If you ask the water authority they will say that the water leaving their plant is potable. But it is what happens in the pipes that connect to your house/condo etc that is important. We use particulate filters for all uses other than drinking & they are brown within 48 hours and are replaced after 2 months. There is so much dust in the mains. For drinking, ice making and cooking we have a 4 stage filter plus UV unit. And we have found this is totally adequate. The real issue to my mind is the unknown use of untreated artesian water by condos, houses and commercial enterprises. I know of one large city centre condo that has all it's units supplied from it's our well, and it is not guaranteed potable. So it is just simple carefulness to drink bottled or RO water. It is not expensive and easy to get.

Depending on where you live your tap water is either from a dam or artesian well.

If the latter, a ~40m bore will produce potable water which really only requires simple 3 stage filtering although a large sediment pre-filter may be desired.

Thanks Rob. But again, if it "requires simple 3 stage filtering...." exactly WHY?

Chlorine I'm not that worried about, because high concentrations can be gassed off by exposure to air for a while.

Filters can remove particulates, nitrates, fluoride, some other compounds and most pathogens (depending on the filters used). But some of this can be done with portable UV sterilisation (much easier if I’m not staying in CM for a long time). Sure, I agree that a good filtration system with final stage ozonation/UV treatment (or RO) is the way to go in a perfect world, but not really feasible if I’m travelling around.

Point taken as well about variability in water source quality depending on location.

Rob.

3 stage underbench filtering makes our (artesian pre-filtered) water taste great (#2carbon filter) and removes any final impurities via a ceramic cartridge(#3).

Our 3 stage system requires 2 filters changed every 6 months and ceramic @ 12months. The whole of house prefilter having removed most of the heavy metals, sand particles etc, means we have excellent drinking water from the 'small' tap on our kitchen sink.

If our water was from a dam or rainwater tank then I'd consider UV treatment.

The last filter should be a U.F. filter, removes 99.99% of all bacteria and viruses.

KDF 55 will remove most heavy metals and chlorine.

A small tank 1.5 m3 and automatic pump to hold the incoming water lets the dirt settle out and lets the chlorine "out gas". and you have the added benefit of having a water reserve in case of loss of the water supply.