What are the most sustainable options for filtering tap water for drinking?

Question

I live in Europe (Belgium), where tap water is generally safe for drinking, but may vary in hardness and taste. It's pretty hard and not so good in my area, so I've been using (Brita) water jugs for a while now. I find this unpractical as somehow the jug is always empty when you need it, and it does not seem very ecological as it requires changing the (plastic-cased) filter every month or so, and the jug itself is not really durable, so I'm now looking into alternatives that are at least equally effective but more sustainable, preferably in the form of a small filter with an extra tap for drinking water, or a filter that can be mounted to the tap directly (Brita sells that as well, with slightly longer lasting filters, but you still end up buying and throwing away a lot of plastics). Physical space is a constraint.

I did some research but I find it hard to find independent and scientifically reliable information on this topic: basically every producer seems to propose the "ideal" solution and claims that everything else is bad for you and/or the environment. Here's the little I learnt, divided by filtering purpose

For softening

• the most reliable approach seems to be based on ion-exchange, using salt whose Na+ replaces the Ca+ in the water. However this takes a lot of space which we don't have, the salt has to be replaced periodically, and I'm not sure of the impact of using that much salt on the environment; moreover, comments to this answer raise doubts on its impact on human health.
• an approach based on Zinc: supposedly you just cascade a small zinc-releasing pipe into your main pipe, and it softens your water during several years (I somehow find this one hard to believe)

For filtering potentially harmful residuals, aside from Brita(-like) solutions:

• I found one product combining ceramic, silver, active carbon, and a cellulose filter which claims to remove a lot of contaminants, which is reasonably small and requires changing the filter every 8k liters
• This product optionally includes a zeolite filter for removing "heavy metals", but these are reasonably scarce in our tap water, and the filter is based on Na+ ion exchange: in this case there's no salt to replace but the health concern remains. Moreover, zeolites contain aluminum (however this may simply not be an issue if it stays bound in the filter)
• Other alternatives on the market are based on "energisation" and "water memory", all of which sounds like new age mumbo jumbo to me (but thanks for proving me wrong)

For sterilization

I trust my provider to kill bacteria and co., so I'm not interested in sterilizing the water.

Answer 1

I live in Bulgaria where water is also generally safe to drink. However, the quality varies and sometimes a lot of chlorine is added to it. Also, there are areas here that go without tap-water some parts of the year. Luckily, there are many springs here so it's usually possible to find reasonably good water.

Still, because water is such an essential part to life, we wanted to ensure a more reliable and sustainable source of good water. So we also looked into filters a lot. We found quite a few options and have chosen to settle on a filter that purifies the water. Sustainable for us meant:

• as little plastics as possible
• natural materials where possible
• a minimal amount of disposables
• simple, so easy to install, maintain and repair
• recyclable

We settled on a ceramic water filter, which according to Wikipedia are:

an inexpensive and effective type of water filter, that rely on the small pore size of ceramic material to filter dirt, debris, and bacteria out of water.

I think the cost of a system, measured over several years, can also be a good indication of sustainability. So for us this cost-comparison was valuable. Please note it is a post from a dealer of a main ceramic water filter manufacturer and supplier, so it may not be completely unbiased. At the same time, the post is positive about competitive systems as well, pointing out they all have their merits, so personally I think it's a useful comparison.

We ended up buying a system that holds water in a metal container, which then gravity feeds through a set of ceramic purifying elements, into a second metal storage container.

The manufacturer produces various sizes, so there might be a size that works in your setup as well.

We pour the filtered water into glass jugs, which we then use troughout the day. We don't cool the water, but you could if you'd prefer that. I know other people leave the filtered water in the metal container, which also works. But for us this works well.

One of your concerns seems to be water hardness/softness. We've also thought about this, but decided against a separate water softener, because in our minds the minerals that water takes up from flowing through soils and rocks are valuable to our bodies. In the past we've lived in an area with very hard water and at that time we looked into it quite deeply. Our conclusion from the research we found was that hard water is not a health hazard, and this is also our personal experience; it's never given us any trouble. This article about water hardness may be a useful overview.

For use in appliances like our washing machine we also don't soften our water, but use an inexpensive, white vinegar. Our personal experience is this works exceptionally well in keeping the machine free from mineral deposits. And if you search for vinegar as a water softener, you'll find plenty of examples of people with positive experiences with it.

I hope this helps you in your search for the most sustainable solution for filtering tap water for drinking.

Answer 2

One option that would allow you to forgo filter disposal altogether, as well as provide you with purified water, would be to use a water distillation unit. These are available in benchtop models such as this example