Coffee

Currently use a Brita filter as its enough to take the chemically smell from my tap water. Espresso machine has a built in water softener that I change every six months or so. It isnt the most efficient way to do it but the machine does not have any build up when I have checked, my water tastes neutral and nice to drink if not amazing.

Long term I want to build in a proper water purification, strip, and remineralization solution into my mains supply when I get around to redoing the kitchen. UK is low risk for water contamination but we do have recent incidents of it happening so its not zero risk and I would rather not take the risk with the way our water companies are ran.

We use rainwater harvested from the roof of our house and the rain comes from the southern Indian Ocean.

I have an RO, for reasons. It cost less than the cheapest espresso grinder that’s acceptable, but it has ongoing maintenance costs.

Edit - if you want to get nerdy, a permeate pump and/or high inlet pressure (which is largely out of our control) helps with the longevity of the membrane; I get about 2 years on mine and my intake water TDS is 500ppm; I replace around 75ppm outflow which is higher than “normal” but the water is designated safe to drink to begin with. Basically, the greater the delta in pressure between the inlet and outlet, the less waste is produced and the longer the membrane lasts.

My solution was to be born in the country with the cleanest tap water.

I can only speak to the U.S. and Thailand, but those two are so disparate I always assumed it must be fairly universal. Maybe Italy has something like it too…

They both have reusable water bottle delivery available in ~5 gallon/~20 liter bottles typically used for water coolers. In the U.S. the delivery costs are pretty ridiculous so many grocery stores also run little bottle exchange kiosks where you can return your empties and pick up full bottles.

RO is really nice. Frankly a lot easier decision if your water isn't already tasty as it tastes great, but bigger deal to install if it's exclusively for coffee. I'd probably try at least one more simple sink filter if you haven't already and see if it's better.

In India, the tap water is not safe to drink, so we have a water filter. The water tastes good enough for the coffee.

You could get a similar reverse osmosis filter.

Sink.

For a couple hundred $/Euros, a 7 stage undersink reverse osmosis filter system with final stage remineralization is more than good enough for most folks. Gives very low TDS (total dissolved solids) and removes all odd flavors from the water. The three main large particle filters need to be changed about once year and cost very little. Works very well for my drinking water and coffee here in Vietnam.

I invested in a water distiller (a cheap Vevor clone of the Megahome) and I remineralize following this recipe. I live in a place where the water is so hard there is a spoonful of calcium carbonate "sand" at the bottom of the distiller. Not just deposit on the sides, actual silt.

You may have a local water distiller where you can take refillable containers. This is what I did prior to installing an RO system. My local one had a 24/7 refill station so I could refill whenever I wanted. It's significantly cheaper than buying from a store, reduces plastic use long-term, and you're shopping local. From there, you can use Barista Hustle's water recipes in order to try out different mineral contents. Personally, I preferred this because it's significantly cheaper than buying the mineral packets and allowed for more experimentation.

I used a 3 stage filter and whole house water softener. With that said, getting one of those larger bottles for water coolers could reduce your plastic usage. I think they sell pumps for them.

Using the Brita ultra filter pitcher.

Lifestraw filter pitcher. We have hard water and good coffee, so I guess it's working.

I just used tap water, although I did install a whole-home water filter about a year ago, so all the water goes through a pre-filter, a pretty substantial filter with carbon filtration, and then also a water treatment process called TAC (Template Assisted Crystallization) which doesn't get rid of hard water but makes it easier to clean and remove hard water scales.

I pretty much just make Americanos these days at home, but I have yet to have a better cup from a store and I don't really buy expensive beans or anything.

I use a ZeroWater filter to get down to 0 Total Dissolved Solids and then third wave packets to reintroduce good minerals for coffee. Its still the case for me that this is cheaper than trying to buy distilled water or using distillation. Reverse osmosis is probably cheaper overall but a lot more initial outlay and it depends on how much water you need.

Brita and other similar small filters do a poor job of removing total dissolved solids (for me its the difference between 260 and 245 which is almost none removed) so they don't change the situation for coffee extraction all that much

Automatic Distiller

I consider it to be as important a home appliance as a fridge now

There're countertop models as well (much more affordable) but the automatic ones with a pump which you can set up to dispense at your choice of locations are unbeatable in terms of convenience

We used bottled for a while (~10 months) before getting a distiller because I couldnt be assed reinstall my ro system at our new apartment. Be as concerned about the microplastics you're drinking if you're doing that aa much as the waste that goes in the bin