Water Treatment Spare Parts

A water treatment system does not deliver its performance on the day it is installed; it keeps performing only as long as its spare parts are replaced on time. When a filter cartridge blocks, the flow rate drops; when a membrane tires, the conductivity of the outlet water rises; when the resin fills its capacity, hardness comes back. At Water Point we supply the spare parts for every stage under one roof, from domestic units to industrial systems: filter cartridges, membranes, valves, resin and activated carbon, tanks, pumps, taps and measuring equipment. Three things decide a spare part: what the part does, how it is chosen and how often it is replaced.

Why a Water Treatment Spare Part Is Critical

A treatment system is made up of stages connected in series. Each stage protects the next one. If the pre-filter does not hold sand and sediment, the carbon filter blocks early; if the carbon filter does not hold chlorine, the reverse osmosis membrane is damaged; and once the membrane has tired, the final mineral stage can do nothing on its own. Replacing a spare part is therefore not a maintenance line item but part of the way the system works.

A replacement left undone has three typical consequences:

• Flow rate drop: The water from the tap slows down, and in systems with a tank the filling time gets longer. The most frequent cause is a blocked sediment or carbon cartridge.
• Change in water quality: A noticeable change in taste and odour, a rising TDS value, hardness returning in softening systems.
• The expensive part running out early: Because a pre-filter worth a few hundred lira is not replaced, the life of a membrane worth thousands is cut short. In spare parts the most expensive option is the cheap part that gets neglected.

Filter Cartridge Sizes: 10, 20, 30 and 40 Inch

Cartridge filters are made in standard sizes. The first step in choosing the right part is knowing the length and the diameter of your housing. When the size does not match, the cartridge does not seat in the housing or it leaks past the side.

Standard (slim) cartridges

These are roughly 6 cm in diameter. Almost every domestic under-sink unit uses a 10 inch standard cartridge. The 20 inch version is preferred where a higher flow rate and a longer replacement interval are needed.

Big Blue (jumbo) cartridges

These are roughly 11–12 cm in diameter. They are found at flat inlets, building inlets and in commercial use. Because they offer far more filter surface at the same length, the flow loss is lower and the replacement interval is longer. A Big Blue cartridge does not fit a standard housing, and a standard cartridge does not fit a Big Blue housing.

30 and 40 inch cartridges

These are used in industrial-type and industrial pre-treatment lines, at points where a high flow rate is needed. They are usually connected in parallel inside multi-cartridge housings.

Filter Types and What Each One Does

The housing sets the size, the type sets the job. You can fit a sediment, carbon or mineral cartridge into the same 10 inch housing; which one you fit depends on the problem in your water and on the job the stage has to do next.

Spun (polypropylene) sediment filter

It is made by compressing melted polypropylene fibres. It holds suspended solids such as sand, sediment, rust and silt. It is the first stage of every system. 5 micron is the most common pore rating; in water with high turbidity it is used together with a coarser pre-stage.

String wound sediment filter

It is made by winding yarn onto a porous core. Thanks to a pore structure that graduates from the outside inwards, it holds particles throughout its volume; that is why it offers more dirt-holding capacity than a spun filter of the same micron rating. It is preferred on well water and on mains water with a high sediment load.

CTO carbon block filter

It is made by pressing activated carbon powder into a block. It holds chlorine and the taste and odour compounds that come from chlorine. Thanks to the block structure it also behaves like a fine sediment stage. In reverse osmosis systems it is important that it sits ahead of the membrane; chlorine wears the membrane surface.

GAC granular activated carbon filter

It contains activated carbon in granular form. It works by letting the water flow through the carbon bed; the pressure loss is lower than with CTO. It is used for taste and odour removal and for holding organic matter. In reverse osmosis systems it is also often placed after the membrane as the final stage.

Washable steel and collared filters

These have a stainless steel screen structure. They are not thrown away like a cartridge; they are taken out, cleaned and used again. On well and mains lines where coarse sediment is heavy, they are positioned as a pre-stage to extend the life of the consumable cartridges.

Mineral, alkaline and taste filters

These are used at the final stage to put minerals back into the water leaving reverse osmosis and to raise its pH value.

Ready-made filter sets

For those who would rather not pick the stages one by one, ready-made sets are available:

Reverse Osmosis Membranes

The membrane is the working heart of a reverse osmosis system. Its semi-permeable surface lets water through under pressure while leaving most of the dissolved salts on the feed side. Three things decide the membrane choice: diameter and length, the salinity of the feed water and the operating pressure.

Domestic 1812 membranes

This is the standard size for under-sink units (1.8 inch diameter, 12 inch length). The daily production capacity is expressed in gallons. The membranes and the housing the membrane sits in:

4 inch (4040) membranes

These are used in small and medium-sized commercial systems.

Low pressure (ULP/LP) membranes run on less pump energy; they are preferred on low-salinity sources such as mains water.

8 inch (8040) industrial membranes

These are the standard for industrial lines. They are arranged in series and in parallel inside pressure vessels to reach the required capacity. The membranes and the pressure vessel they go into:

Seawater membranes

These are membranes designed for high salinity, with a thick construction and resistance to high pressure. They cannot be swapped with a mains water membrane.

Valves: Replacing the Brain of the System

The valve on top of the softening and filtration tanks runs the backwash, brine draw, slow rinse and fast rinse steps in sequence. When the valve fails, the system does not work even though the tank and the resin are sound. The valve choice also decides directly how efficiently the system will use salt and water.

Time-controlled (timer) valves

These start the backwash by calendar or by clock. Because they run independently of water consumption, they are the simplest option to install and use; in return they can regenerate unnecessarily during periods when little water is used.

Flow-controlled (volumetric) valves

These count the volume of water that passes and start regeneration only once the capacity is used up. They lower salt and water consumption; the difference is clear where consumption varies.

Clack, Fleck and Runxin

All three brands address different budget and capacity ranges.

Valve spares and ancillary parts

Replacing the whole valve is not always necessary; most leaks and position faults come from an O-ring or a piston.

Resin, Activated Carbon and Consumable Chemicals

Unlike cartridge filters, the media inside a tank is used for years — but it is not endless. When its capacity drops it is renewed.

Cationic resin — water softening

It removes hardness by exchanging the calcium and magnesium ions in the water for sodium. When it reaches saturation it is regenerated with brine; this cycle can be repeated thousands of times. Breakage, fouling and contact with chlorine shorten the life of the resin.

Mixed bed resin — pure water

It is a mixture of cationic and anionic resin; by holding both positive and negative ions it produces deionised water. It is used as the final stage after reverse osmosis in laboratories, steam boilers and sensitive production lines. Mixed Bed Pure Water Resin 24,509.20 TL.

Activated carbon

This is the media for tank-type carbon filters.

Membrane protection and line chemicals

The line chemicals used on industrial reverse osmosis lines:

These chemicals are applied with a dosing pump and on the basis of measurement.

Tanks and Pressure Tanks

There are two different tanks and they must not be confused. The pressurised storage tank collects the water the reverse osmosis unit produces; it contains an air cushion, and when the tap is opened it is that pressure which pushes the water out. The media tank carries resin or activated carbon and works together with the valve.

Storage tank volume is chosen according to how heavily the system is used:

On the media side, Sand, Carbon and Softener Vessels at 6,372.39 TL are used.

Pumps

Mains pressure is often not enough for reverse osmosis. For the membrane to work, the feed pressure needs to be above a certain threshold; the booster pump takes on that job. The capacity must be chosen to match the daily output of the unit.

Taps and Dispenser Adapters

Treated water is delivered from a separate tap. Unlike a standard kitchen mixer, a filter tap has the surfaces that touch the treated water made from material suited to that duty.

Measurement and Test Equipment

Planning spare part replacement by measurement rather than by guesswork prevents both unnecessary cost and being too late. Three simple instruments are enough.

• TDS meter: Shows the total dissolved solids in the water. A value at the reverse osmosis outlet that rises over time indicates that the membrane has tired. TDS Meter 1,225.46 TL.
• pH test kit: The most practical way of telling whether the alkaline and mineral filters are still doing their job. pH Test Kit 588.22 TL.
• Limescale (hardness) test kit: Shows whether hardness has come back at the outlet of the softening system; it is the basis of the resin and valve decision. Water Hardness Test Kit 1,176.44 TL.
• Water filter jug: Used as a temporary solution where a system connected to the mains cannot be installed. Water Filter Jug 3,186.20 TL.

Spare Part Replacement Intervals

The intervals below are for typical mains water and average use. If your water is hard, high in sediment or drawn from a well, the intervals get shorter. The right approach is to take the calendar as a starting point and to settle the decision by measurement.

5 Steps to Choosing the Right Spare Part

The three most frequent reasons for buying the wrong part are size confusion, a mismatched connection diameter and a capacity error. If you follow this order, the margin for error drops:

• 1 — Identify the housing and the size. Standard or Big Blue, 10 or 20. If there is no printing on the cartridge, measure its length.
• 2 — Be clear about what the stage does. Is this stage holding sediment, is it holding chlorine, or is it adding minerals? Changing its job upsets the balance of the system.
• 3 — Measure the problem in your water. Hardness, TDS and pH are the three basic figures. Test kits give all three in a few minutes.
• 4 — Check the connection diameter. On valves and taps 3/4″ and 1″ are easily confused; bypass and fitting compatibility must be confirmed before you buy.
• 5 — Match the capacity to the unit. The daily output figure of the pump and of the membrane must suit each other and the volume of the tank.

Wherever you are not sure, it is enough to send us the brand and model of your unit; we will work out the right part together.

Common Faults and the Part Responsible

The Difference Between an Original Part and an Equivalent

On standard-size parts such as filter cartridges, using an equivalent is common and usually causes no trouble; what matters is that the size and the micron rating match. On the membrane, valve and electronic board side the situation is different: the salt rejection rate and pressure resistance of a membrane, and the flow capacity and programming logic of a valve, vary from brand to brand. On these parts, going outside the class the system was designed for may look cheap in the short term, but it comes back as lower output and early failure.

At Water Point the membranes we sell are Toray, LG, STAR, TechFlow and FilmTec; on the valve side we use Clack, Fleck and Runxin products.

What Is Different About Buying Spare Parts from Water Point

• Valves, pumps and tanks carry a 2-year warranty and taps a 1-year warranty; consumables such as filters, membranes and resin are outside cover. Misuse is outside cover in every case.
• CE certified products — we work with products that fall within certification scope.
• ETBİS-registered e-commerce — we are registered in the Ministry of Trade’s Electronic Commerce Information System.
• Invoiced sales — a legal invoice is issued with every order, so accounting for corporate purchases is straightforward.
• Free site survey available — if you are not sure which part needs replacing, we identify the fault first. see the details
• Türkiye-wide service network for industrial systems — for domestic units we serve İstanbul and the surrounding provinces (such as Kocaeli and Tekirdağ).
• Standard-size cartridges — we hold stock in 10, 20, 30 and 40 inch standard and Big Blue sizes.
• 20+ years of field experience — application experience from domestic to industrial systems under our founder Ali Genç.

Address: Mehterçeşme Mah. 1919 Sk. No: 54/B Esenyurt / İstanbul.

Spare Part Plan for Well Water and Hard Water Areas

The replacement intervals given for mains water do not hold for well water. Well water usually carries a higher load of suspended solids, iron, manganese and micro-organisms; that tires the early stages far faster. On sources where sediment is heavy, positioning a washable steel filter ahead of the consumable cartridge, instead of putting that cartridge straight at the head of the line, clearly lowers the cartridge cost.

In hard water areas the real load is on the softening side. As hardness rises the resin regenerates more often, salt consumption goes up and the valve runs more cycles. In that case choosing a flow-controlled valve saves both salt and water compared with a time-controlled valve. Because the life of the resin depends directly on the number of cycles, the right valve choice also lengthens the resin replacement interval.

• Well water: A washable steel filter at the pre-stage, then a string wound sediment cartridge. The carbon stage must sit behind these.
• High hardness: A flow-controlled valve, regular salt top-ups and an outlet hardness measurement at least once a year.
• High sediment: Going up a cartridge size (20 inch or Big Blue instead of 10 inch) reduces how often it has to be replaced.
• Microbiological risk: If a UV (ultraviolet) treatment stage is in use, the lamp interval must be tied to a calendar.

Spare Part Stock in Industrial Systems

In a treatment system tied to a production line, the real cost is not the part itself but the downtime. That is why the right approach for industrial users is not to hunt for a part once a fault appears, but to keep the critical items in stock beforehand.

In practice three items count as priorities: pre-filter cartridges (the item that is replaced most often and the cheapest), a valve O-ring and piston kit (which resolves the large majority of leaks and position faults) and at least one spare membrane (the part with the longest lead time). Alongside these, keeping consumables such as antiscalant and salt continuously in stock is decisive in keeping the system running at its planned efficiency.

As capacity grows, so does the amount tied up in membranes and valves. Given the price range of 8 inch membranes and high-capacity valves, replacing the early stages regularly turns directly into a saving. A simple maintenance calendar protects a membrane worth tens of thousands of lira with a cartridge worth a few hundred.

In our Water Treatment Spare Parts category you can find the parts for every stage, from domestic to industrial scale, and by sending us the brand and model of your unit you can work out the right match together with us.

Water Treatment Spare Part Prices 2026

The prices below are the current values on the product pages and include VAT. When there is a campaign on a product page, the valid price appears there.

Spare parts for every stage are listed in this category. If you cannot see the part you are looking for in the list, contact us with the brand and model of your unit.

Could not find the spare part you are looking for?

Send us the brand and model of your unit and we will determine the right filter, membrane, valve or resin together. If the unit is purchased from us the site survey is free; if only a survey and measurement are requested, a 2,000 TL site survey fee applies.