A water filter is the rare purchase where the thing you buy on day one is not really the thing you are buying. What you are actually buying is several years of a machine that keeps working, and the machine only keeps working if somebody changes what is inside it on schedule.
That is what an annual maintenance contract is for, and it is worth being specific about what it includes, what it does not, and what happens to people who let it slide — because the last of those is the part the industry tends to leave vague.
What is actually in the plan
Four things, and they are not complicated.
Two scheduled visits a year. Not one, and not “as required”. Filter cartridges are changed roughly every six months, so the plan is built around two visits spaced about that far apart. The reason it is scheduled rather than requested is covered further down, and it is the whole argument.
The cartridges themselves. The consumables are included, not billed on the day as an extra. This matters more than it sounds, because a plan that covers the visit but charges for the parts leaves you making a small purchasing decision twice a year, and people under mild financial pressure make that decision by postponing it.
The labour. A technician comes to you, does the change, checks the system for leaks and flow, and leaves. There is no separate call-out fee bolted on at the end.
From year two onwards, the warranty. A new system comes with 12 months of warranty and 12 months of maintenance included. After that first year, an active maintenance contract is what keeps the warranty alive. If the plan lapses, so does the cover.
The point everyone misses
Here is the thing that makes maintenance a different sort of expense from an extended warranty on a television.
A filter is not a thing you buy. It is a thing you maintain. The machine on your wall is a housing, some tubing and a tap. The part that does the work is the cartridge inside it, and that cartridge has a finite working life measured in litres and months.
Take activated carbon, which is the stage doing most of what you notice. Carbon works by adsorption: the material is riddled with microscopic pores giving it an enormous internal surface area, and chlorine and various organic compounds stick to that surface as water passes through. It is a finite surface. Once the pores are occupied, they are occupied. A saturated carbon block is not a filter — it is a cartridge holding everything it has already collected, with water running past it.
The same logic applies down the line. A sediment cartridge fills with what it has caught. A membrane fouls. Every stage in the machine is a consumable pretending to be a component.
The problem you cannot see
This is why we say, bluntly, that an unmaintained filter is worse than having no filter at all.
Not because it does something harmful, but because of what it does to your judgement. A spent cartridge keeps passing water long after it has stopped doing much, and there is no way to tell from the outside. The tap runs. The water is clear. Nothing beeps. In our experience the taste change is gradual enough that most households do not consciously register it, because the decline happens over months and the human palate adjusts as it goes.
So the family carries on believing the water is being treated, and drinking it on that basis, when in reality the treatment stopped somewhere in the previous few months without announcing itself. Somebody with no filter at all knows exactly where they stand and can make decisions accordingly. Somebody with a filter that stopped working in March cannot.
That is the honest case for a scheduled plan, and it is not a sales argument about our cartridges being special. It is an argument about the fact that a service you have to remember is a service that eventually gets forgotten, and this particular one fails silently.
What happens if it lapses
Nothing dramatic happens on the day. That is rather the problem.
The machine carries on running. The cartridges carry on ageing past their service life. Flow usually drops off first — a clogged sediment stage restricts it noticeably, and people often mistake that for a plumbing issue. Taste and odour come back, generally slowly enough that nobody puts a date on it.
The change that is immediate rather than gradual is the warranty. From year two, cover depends on the plan being active. If the machine develops a fault while the contract has lapsed, the repair is chargeable, and it is chargeable at exactly the moment you were least expecting a bill.
Restarting after a lapse is straightforward and we are not going to be difficult about it. What we cannot do is retrospectively cover a fault that occurred while it was inactive.
Can you just do it yourself?
Yes, and we would rather say so than have you find out from somebody else that we did not mention it.
You can buy cartridges and fit them yourself. On most under-sink and counter-top systems it is not difficult work — you isolate the supply, depressurise, swap the cartridge, flush the new one through and check for leaks. Plenty of practically-minded people do it perfectly well.
What you give up is worth stating honestly, because it is not nothing.
You give up the schedule. This is the big one, and it is the reason most self-servicing quietly stops after eighteen months. Nobody sets out to skip a change; they postpone one during a busy month, and the next reminder is one they set themselves. If you are going to self-service, put both dates in a shared calendar the day you buy the machine, not the day you first notice the flow has dropped.
You give up the second pair of eyes. A technician changing a cartridge is also looking at the fittings, the tubing, the tap and the pressure. Slow leaks under a sink are found this way regularly, usually before the cabinet base is damaged.
You give up the warranty from year two, since that is tied to an active contract.
And you take on the sourcing problem. You need the right cartridge for your machine, from a supplier you can rely on, twice a year, indefinitely. This is worth asking about before you buy any system from anyone, ours included: what does a replacement cost, and where can you get it.
For a household that will genuinely keep to the schedule and does not mind the sourcing, self-servicing is a legitimate choice. For most households, the value of the plan is not that the work is hard. It is that somebody else is responsible for remembering.
How often is “roughly six months”?
Six months is the working assumption, not a law. Actual cartridge life depends on how much water the household draws and what is in the supply locally, so a large family cooking at home daily works through a cartridge faster than a couple who are away half the year. We have gone into the variables in more detail in our guide to how often to change a water filter here.
What the schedule gives you is a floor. Twice a year is frequent enough that a heavy-use household is not running badly overdue, and a light-use household is not wasting much. Precision beyond that would require measuring your consumption, which is more effort than the thing is worth.
Two things a plan is not
It is not insurance against accidental damage, and it is not a cover-all for anything that happens to the machine. It covers scheduled servicing and, from year two, keeps the manufacturer’s warranty in force. A cracked housing from a knock is a different conversation.
And it does not change what the machine does. A plan keeps a system performing as designed; it does not add stages, and it will not make water cold. Filtration and cooling are unrelated — a standard under-sink or counter-top system delivers water at tap temperature, which in a UAE summer is warm, and cold water requires a machine with a chiller in it.
What it costs
Deliberately not stated here, because prices change and an article quoting a stale figure is worse than one that quotes none. The current plans, and which one fits which system, are on our maintenance page, which is the authority on it.
What we would say about cost generally is this: judge it against the machine, not in isolation. The system is the smaller commitment and the servicing is the larger one over any sensible ownership period, which is exactly why we set out what a filter really costs over several years rather than only the day-one price. Any company that will not tell you the year-two number before you buy is telling you something about how it intends to make its money.