This page is a translation of the Italian version, which remains the reference text. The service is installed in Italy, in Lazio and Emilia-Romagna. Read the Italian original
What a water purifier costs
It depends how you take it on, and the difference is not small. Buying one costs between a few hundred and a few thousand euros up front, plus filters and servicing every year. Renting one costs a monthly fee, but almost always with a minimum term. Having one on subscription costs nothing up front and puts everything into a single payment.
The right question, though, is not what the appliance costs: it is what it costs to keep it running for three years. That is where the sums turn over, because the items people forget — filters, membrane, sanitisation, a repair — weigh as much as the system. Below are all three routes with the sum in full, and at the end what AcquaStream costs.
Try it free for 30 days €29,90 a month if you stay. Nothing up front, no penalty.
The three routes, in brief
| Buying it | Renting it | On subscription | |
|---|---|---|---|
| Up front | €350 – 2,500 | €0 – 150 | €0 |
| Each month | — | €20 – 45 | €29.90 |
| Filters and servicing | yours | usually included | included |
| If it breaks | you pay | depends on the contract | included |
| Minimum term | none | often 36 – 60 months | none |
| Who owns the system | you | whoever rents it to you | whoever lends it to you for use |
| If you stop | it stays with you | you give it back | they collect it |
The line that matters most is the minimum term. That is what turns a low monthly fee into a committed expense for three or five years, and it is the first thing to look for in a contract, before the price.
What it costs to buy a reverse-osmosis purifier
The price of the system depends on how many filtration stages it has and on what it does besides filtering. These are indicative bands for the Italian market as at October 2026:
| Type of system | Indicative price | What it does |
|---|---|---|
| Basic under-sink kit, self-assembly | €150 – 400 | filters and nothing else, you fit it |
| Under-sink reverse osmosis, 4–5 stages | €400 – 900 | filters and remineralises |
| With a carbonator for sparkling water | €900 – 1,800 | still and sparkling |
| With carbonator and chiller | €1,500 – 2,500 | still, sparkling and cold |
On top of that comes the installation, if you do not do it yourself: a plumber charges roughly €150–350, more if a socket has to be run under the sink or the worktop drilled for the tap.
The items almost nobody counts
These are what make the difference over three years, and they rarely appear in a quote:
| Item | How often | Indicative cost |
|---|---|---|
| Filters (pre and post) | 6 – 12 months | €80 – 200 a year |
| Osmotic membrane | 2 – 4 years | €60 – 150 |
| Sanitising the system | every year | €80 – 150 |
| CO₂ refill (if you have sparkling) | depends on use | €15 – 30 a cylinder |
| Repair out of warranty | when it happens | from €100 up |
Two items that are often raised and in practice weigh little: electricity, because a domestic osmosis system without a chiller uses about as much as a light bulb, and the waste water, which is real — osmosis sends a share of what it filters down the drain — but is worth a few euros a year on a household bill. If you do have the chiller, though, the electricity starts to count.
What it costs to rent a purifier
Renting moves the cost from the start to the monthly fee: you begin with little or nothing and pay every month, with filters and servicing usually included. Offers on the market sit roughly between €20 and €45 a month, depending on what the system does.
The two things to read before signing are always the same. The minimum term: many rentals run from 36 to 60 months, and getting out early costs. What happens at the end: in some contracts the system stays with you, in others you return it, in others again a new fee starts.
If the fee is €30 a month for 48 months, the outlay is €1,440: that is what has to be compared with buying, not the zero at the start.
What AcquaStream costs
AcquaStream is a subscription, not a purchase: the system stays with the company supplying it and is given to you on free loan for use. The fee is €29.90 a month. The installation costs €120, once only, and is paid only if you decide to stay after the 30-day trial.
| When | What you pay |
|---|---|
| At installation | €0 |
| During the 30-day trial | €0 |
| If you cancel by day 30 | €0, collected at our expense |
| From day 31, if you stay | €149.90 (€29.90 for the month + €120 installation) |
| From the following months | €29.90 a month |
The fee covers the system and the tap on free loan, the carbonator for sparkling water with the first CO₂ cylinder, scheduled filters, servicing, support and repair or replacement of the system. What stays on you is the mains water and the electricity the system uses, and the CO₂ refills after the first. There is no minimum term: you cancel when you like. The terms in full.
The sum over three years
This is the comparison that actually matters. Assumptions: a mid-range system with a carbonator, a household of three, filters changed when they should be, no extraordinary repairs.
| Buying it | Renting it | AcquaStream | |
|---|---|---|---|
| System | €1,200 | €0 | €0 |
| Installation | €250 | €0 | €120 |
| Monthly fees (36 months) | €0 | €1,080 (€30/month) | €1,046.50 (35 months: the 1st is the trial) |
| Filters and membrane | ≈ €420 | included | included |
| Sanitising | ≈ €300 | included | included |
| Total over 3 years | ≈ €2,170 | ≈ €1,080 | ≈ €1,166.50 |
Two things this sum says, and both are worth reading in full. First: over three years buying costs more, because the system is paid for all at once and the servicing stays on you. Second: renting and subscribing end up close together, and the difference is not the total but what happens if you change your mind — with a 48-month minimum term that €1,080 becomes €1,440 and cannot be stopped.
Beyond three years it turns over again: whoever bought carries on paying only for filters and servicing, so around the fifth or sixth year buying catches up. If your horizon is long and you are happy to manage the servicing, buying makes sense.
And compared with bottled water?
Here the figures move a great deal depending on how much you drink and which water you buy, so it is worth doing the sum on your own habits rather than trusting an average.
A household of three drinking around a litre and a half each a day gets through about 1,600 litres a year. At €0.25 a litre — a branded mineral water at the supermarket — that is roughly €400 a year; at €0.12 a litre, the price of a cheap bottle on offer, about €190.
With the fee at €29.90 you spend €358.80 a year. Which means that against a branded mineral water the sum adds up, against the cheapest bottle it does not: if you buy water on offer and drink little of it, the switch does not pay for itself in euros. What changes anyway is the rest — not carrying the crates, not storing them, not disposing of the bottles, and having sparkling water without buying it.
The same holds for someone living alone: at that level of use a fixed fee weighs more than what is spent on bottles. It is right to know that beforehand, not afterwards.
When a purifier is not worth it
For honesty, the cases where the answer is no:
- If you drink little water. Below a litre a day per person, any monthly formula costs more than you spend on bottles.
- If you have no space under the sink or no socket nearby. A reverse-osmosis system takes up its own room, and feasibility is checked beforehand.
- If all you want is to get rid of limescale. That is a water softener's job, which is another thing and costs differently: osmosis works on the water you drink, not on the water in the radiators and the washing machine.
- If you are about to move. With a purchase you take a system with you that has to be refitted; with a minimum-term contract you pay anyway.
How to read a quote
Four questions to put to anyone, AcquaStream included, before signing:
- Is there a minimum term? And if I leave early, what does it cost.
- Are the filters and the sanitising included, and for how many years? «First year included» is not «included».
- Who pays if it breaks, and when does the warranty run out.
- What happens at the end: does the system stay with me, do I give it back, or does another fee start.
A supplier who answers all four in writing is already good news, whatever the price.
30 days of free water. You only pay if you stay.
We install the system without you paying a single euro up front. If it does not convince you, write to us by day 30: we come and collect it at our own expense, with no penalty.
If you stay, from day 31 it is €29,90 a month plus a one-off €120 installation fee. Cancel whenever you like. The terms
Would you rather talk it through? 347 769 2795.
Request received.
We will call you to check coverage and feasibility. No subscription has been started.
Questions about what a water purifier costs
How much does a water purifier cost per month?
It depends on the formula. On subscription with AcquaStream the fee is €29.90 a month, with filters, servicing and support included and no minimum term. Rentals on the market sit roughly between €20 and €45 a month, often with a minimum term of 36–60 months. If instead you buy the system there is no monthly fee, but filters and servicing remain, worth roughly €150–350 a year.
What does servicing a reverse-osmosis purifier cost?
If the system is yours, the items are the filters (roughly €80–200 a year), the osmotic membrane every 2–4 years (€60–150) and the annual sanitising (€80–150). On a subscription and in most rentals these are covered by the fee: that is the main difference between buying and not buying.
How often are the filters changed, and what do they cost?
Pre-filters and post-filters are changed roughly every 6–12 months depending on use and on the hardness of the water; the reverse-osmosis membrane lasts longer, from 2 to 4 years. Buying them yourself costs roughly €80–200 a year. With AcquaStream the filters are scheduled and covered by the fee.
What does the installation cost?
If you buy the system and call a plumber, roughly €150–350, more if a socket has to be run under the sink or the worktop drilled for the tap. With AcquaStream the installation costs €120 once only, and is paid only from day 31, that is only if you decide to stay after the trial.
Does a purifier push the bill up?
Hardly. A domestic osmosis system without a chiller uses about as much as a light bulb, and the water the process sends to waste is worth a few euros a year on a household bill. If the system has a chiller the electricity use rises and starts to count.
Is it better to buy a purifier or take one on subscription?
Over the first three years the subscription costs less, because buying means paying for the whole system at once and keeping the servicing on you. Around the fifth or sixth year buying catches up, because whoever bought pays only the running costs of servicing. Buying suits someone with a long horizon who does not mind managing filters and support; a subscription suits someone who prefers one payment and nothing to think about.
Are there hidden costs in the AcquaStream subscription?
There are three items and all of them are stated: €29.90 a month, €120 for installation once only from day 31, and the CO₂ refills after the first, which is included. The mains water and the electricity the system uses stay on you, as with any system. There is no minimum term and there are no cancellation penalties. The full terms are on the site.