Installing a Water Treatment System: Steps and Pitfalls

When you open the box you find a body, a few coloured hoses, a tap set, a tank and a few fittings you do not recognise. It does not look complicated at first sight; but a single hose that is not fully seated can turn into a leak that goes unnoticed inside a cabinet for days. So installing a water treatment systemis a stage calling for as much care as choosing the unit.

In this guide we take up the installation process step by step: what should be checked beforehand, in what order the connections are made, what to watch on the first run and the mistakes made most often. And we set out something just as important honestly: in which cases the work must be left to an authorised technical service.

What Is Checked Before Installing a Water Treatment System?

Four headings are checked before installation: the space the unit will sit in, access to the cold water line, a drain connection for the waste water, and whether the mains pressure is sufficient. An installation started without confirming those conditions stops halfway and leads to extra plumbing work.

The preparation stage is the part most often skipped but the one that affects the result most. When the unit reaches you, going over the space where it will be installed rather than moving straight to the connections saves time. What should be checked is this:

The last item on that list matters in particular. Every unit has a different connection layout, hose colour coding and order of stages. This article sets out the general flow; in practice the connection diagram in the unit’s own manual should always govern.

The question of pressure should be settled at the preparation stage too. If the mains pressure is insufficient the unit produces slowly and the treatment performance stays below what is expected; in that case the build should be planned with a pumped system . If the unit has not been chosen yet, we took up in detail which type suits in our unit selection guide .

Choosing Where to Install It

The unit is generally placed in the cabinet under the kitchen worktop. The point chosen should have enough room for the body and the tank, room for service when changing the filters, and easy access. The unit should also be kept away from any direct heat source and from excess damp.

Three dimensions are thought about together when deciding the layout: the space the unit takes up, the position of the tank, and the room to manoeuvre needed during maintenance. A layout that fits at the moment of installation but whose cover cannot be opened causes trouble at the first filter change.

The points to watch are these:

• Room for service: Space should be left in front for opening the body covers and taking the cartridges out.
• The position of the tank: The tank should generally stand upright on a firm base; its hose should not be crushed.
• Distance from heat: A position in direct contact with heat sources such as a dishwasher or an oven should be avoided.
• Checking the floor: Having the floor visible is an advantage so that any leak is noticed early.
• The route of the hoses: The hoses should run without sharp turns, without being crushed and without being stretched.

When an installation is planned, those details should be settled at the outset and not afterwards. When the layout is changed after installation, all the connections have to be taken apart again, and every disconnection and reconnection raises the risk of a leak.

The Plumbing Connections Needed

In a standard installation four connections are made: a quarter-turn valve for the cold water inlet, a separate tap fitted to the worktop for the treated water, a drain connection for the waste water, and the tank line on systems with storage. Every connection has its own job, and when one is missing the system does not work correctly.

Knowing the connections one by one markedly reduces the chance of a mistake during installation:

The cold water connection is the most critical point; when the unit is connected to the hot water line the filters and the membrane are damaged. That is an irreversible mistake and is usually outside the warranty cover.

The choice of tap bears directly on comfort in use too. Standard models are enough for those who want to take treated water from a single point, while those who want to bring different water options together in one body prefer a three-way tap . For those looking for a decorative alternative, luxury treatment taps are a suitable option.

On systems with storage the tank is a separate part of the installation. A water treatment tankof a suitable volume is positioned according to the layout inside the cabinet and connected to the system through its own valve.

Figure 1: The under-counter layout and the plumbing connection points

The Installation Steps

The installation runs in a particular order: the water is turned off, the inlet valve is fitted, the unit is placed, the hose connections are made, the tap is fitted, the drain connection is set up and finally the tank is connected. Changing the order leads to mistakes that call for taking things apart afterwards.

The flow below shows the general logic followed during an installation. In practice the unit’s own connection diagram should govern:

1. Turn Off the Water

   The main valve on the kitchen line is closed and the pressure left in the line released by opening a tap. No connection is touched before that step is done.

2. Fit the Inlet Valve

   A shut-off valve to feed the unit is fitted onto the cold water line. That valve lets you cut off the water during maintenance later on.

3. Place the Unit

   The body is positioned firmly and level at the point planned. A layout is chosen where the hoses can run comfortably.

4. Make the Hose Connections

   The inlet, outlet and waste lines are connected according to the diagram in the manual. Every hose is checked for being fully seated in its connection point.

5. Fit the Tap

   The existing hole in the worktop is used or a suitable point is opened. The tap is fixed and the treated water line connected.

6. Set Up the Drain Connection

   The waste water line is connected to the sink drain with a suitable fitting. The position of the connection point is chosen so that there is no backflow.

7. Connect the Tank

   On systems with storage the tank line is connected and the tank valve opened. The tank is confirmed to be standing upright and firm.

8. Open the Water Gradually

   The main valve is opened slowly; the system is pressurised in stages. Sudden pressure can put strain on the connections.

The First Run and Running Off the First Water

Once the system is pressurised, the first water produced is not used. The dust and traces of the protective agent left in the stages from production and storage have to be washed out. After the tank fills it is emptied once or several times to rinse the system; the water is then ready for use.

That step is often rushed; yet the first rinse bears directly on the taste and the clarity of the water. Newly fitted cartridges can contain carbon dust and the first water out can look grey or cloudy. That is normal and passes with rinsing.

The order to follow on the first run is this: the system is pressurised, the tap is left open to let the air out, and you wait until the flow settles. On systems with storage the tank takes time to fill; that time varies with the capacity and the inlet pressure. Once the tank is full the water is run off, and that operation is repeated as many times as the manual states.

Slight differences in the taste of the water are usual at that stage. The system settles after a few fill-and-empty cycles. For a general framework on installing and using domestic treatment systems, the US Environmental Protection Agency guide to home water treatment can be consulted.

Checking for Leaks and the First 24 Hours

Once the installation is complete, all the connection points are checked one by one. The floor is dried and looked at again a few hours later; even the smallest trace of damp shows that a connection is not fully seated. The first twenty-four hours are the most critical period of observation for an installation.

Leaks usually appear not at the first moment but after the system has reached full pressure. So finishing the installation and closing the cabinet door is not enough. The method of checking advised is this:

• The dry floor test: A dry paper towel is laid under the unit; even the smallest drop is noticed at once.
• Scanning the connections: Every connection point is checked one by one, by hand and by eye.
• Around the tap: The underside of the mounting point on the worktop is inspected separately.
• The drain line: The waste water connection is confirmed not to be leaking and to be discharging properly.
• Checking again: The same points are reviewed a few hours later and again the next day.

Opening the cabinet door and checking often on the first day after an installation is the most practical way of catching a problem early before it grows. A small leak that goes unnoticed can do serious damage to the base of the cabinet and to the kitchen floor over time.

Common Installation Mistakes

The most common mistakes are these: a hose not fully seated in its connection, connecting to the hot water line, positioning the drain connection wrongly, fitting the valve at an unsuitable point, and placing the unit in a cramped space. Each has a different but preventable consequence.

The table below sums up the mistakes together with their consequences:

What those mistakes have in common is that all of them can be prevented by a few minutes of checking at the moment of installation. Putting them right afterwards calls for the system to be taken apart and reconnected. So not rushing during an installation is the most effective protection there is.

Figure 2: Checking for leaks and inspecting the connections after installation

Installation at the Building Inlet and on Central Systems

Installations made on the main line are of an entirely different scope from an under-counter fit. The system is connected to the inlet line after the meter and a bypass valve is essential. The drain connection, the power supply and the space for service should also be planned in advance. Those installations call for an authorised service.

The most critical element here is the bypass valve. On a system working on the main line, when maintenance has to be done, without a bypass the water to the whole building or the flat has to be cut off. In apartment blocks and businesses that is not an acceptable position.

On central installations these are planned in addition: enough space for the tank bodies, discharging the backwash or regeneration waste water, a power supply for the automatic valves, and room to manoeuvre during maintenance. We took up the scope of those conditions and the logic of the installation in detail in our building inlet treatment systems article .

Working on the main line calls for plumbing knowledge and suitable equipment. A connection made wrongly affects not only the unit but the plumbing of the building. For an installation at that scale, authorised service support is not a choice but a technical necessity.

In Which Cases Is Technical Service Essential?

Softening systems, industrial installations, work calling for intervention on the main line, electrical units and riser connections must all be carried out by an authorised service. And the installation conditions laid down by the manufacturer have to be followed if the warranty cover is to be preserved.

This section has to be written clearly, because a wrong choice leads both to material loss and to losing the warranty. In the following cases the installation should definitely be left to a professional:

• Softening systems: The tank, valve, salt tank and drain connection are built together and call for setting up.
• Industrial installations: High flow, heavy equipment and plumbing specific to the project are involved.
• Work on the main line: Every connection made to a building or flat inlet line calls for technical competence.
• Electrical units: Connecting the pump, the automatic valve and the electrical components calls for safety.
• Work on riser lines: Work on the shared plumbing of an apartment block calls for the approval of the management and for expertise.
• Lines with a pressure problem: Whether a pump is needed and the pressure balance have to be assessed correctly.

A simple under-counter installation can be carried out by someone experienced with plumbing, following the manual. But even then the responsibility rests with the user; a possible leak may be assessed as outside the warranty. Taking professional support at every step you cannot be sure of is the safest approach.

The Maintenance Calendar After Installation

The installation is not the end of the process but the beginning. Because the filter stages fill over time, regular renewal is needed. Checking the connections periodically also reduces the risk of a leak. The interval is set by the quality of the inlet water and the intensity of use.

Noting the date of installation once it is complete is a good habit; the first filter change is planned from that date. The headings to keep track of are these:

Renewing the filters is the only regular operation that preserves the performance of the system. We took up step by step which stage is changed when and how the signs are read in our filter change guide . When the time comes, the whole line can be refreshed with a spare filter set suited to the stage layout.

Changing a filter is in fact a small-scale installation: the water is turned off, the body is opened, the cartridge is changed and the system is pressurised again. So the checks you learn during an installation come in useful at every maintenance.

Frequently Asked Questions