Apartment Plumbing - Installation of New Water Supply Systems

The scope varies from one firm to another, so always get it in writing. A typical package includes:

• removing the old water and waste pipes inside the flat
• cutting or chasing channels in walls and floors for the new pipes
• new hot and cold water pipework, most often in PPR
• new plastic waste pipes laid with the correct fall
• connection points for taps, shower, bath, toilet, washing machine and dishwasher
• isolation valves and a pressure test before anything is covered up

Often the package does not include replacing the riser, filling and plastering the chases, tiling, fitting sanitary ware or installing an electric water heater. Customers often expect a "finished bathroom", but the package actually ends at capped outlets sticking out of the wall. Ask in advance exactly where the work stops.

Good plumbing starts with planning, not drilling. The usual sequence looks like this:

1. Survey the flat and agree where the basin, shower, washing machine, sink and dishwasher will go. Moving outlets later is wasted work.
2. Arrange with the building management or owners' association when the water on the riser can be shut off, and confirm where the shared pipework ends and yours begins.
3. Remove the old pipes and prepare the chases in walls and floor.
4. Lay the new pipes, fuse the PPR joints, fix the pipes securely and insulate them.
5. Lay the waste pipes with a steady fall towards the riser.
6. Pressure test the water supply and check the waste pipes while the chases are still open.
7. Close the chases with plaster or prepare the walls for tiling.

In a typical flat the installation itself usually takes a few days, depending on how many outlets there are and how easy it is to reach the pipes.

Old metal pipework is now almost always replaced with plastic. Why? Plastic does not rust, it does not fur up with limescale the way galvanised steel does, it is light and it goes in quickly.

• PPR (polypropylene) is the most common choice in flats. The joints are fused with heat, so pipe and fitting become one piece with no seals. How much heat and pressure it can take depends on the pipe type. For hot water, installers use pipes the manufacturer rates for hot water, often with a stabilising layer that limits expansion.
• Multilayer pipe (PEX-AL-PEX) has an aluminium layer inside, bends easily and suits runs in the floor, for example. It is joined with press fittings, which need the correct pressing tool.
• Plastic waste pipe is only for drainage, never for drinking water.

Copper is still used in some places, but much less often in flat renovations. With good material and correct installation, manufacturers usually expect plastic pipework to last for decades. Insulation matters too: on hot pipes it reduces heat loss, and on cold pipes it stops condensation and keeps the water from warming up next to the hot run.

Even though the package is agreed up front, the condition and layout of the flat have a big effect on the work. The job is easier when:

• the flat is empty, with no furniture and the old tiles already removed
• the bathroom, toilet and kitchen stay where they are
• the risers and stopcocks are easy to reach
• the electrics and floors are being renovated at the same time, so all the chasing happens in one go

The job gets harder if the kitchen or bathroom moves further from the riser, because waste pipes need a fall and room in the floor build-up. Hard masonry, a prefabricated bathroom pod that has to be demolished first, old corroded stopcocks that will not close, or surprises hidden in the walls all add time and material.

Risers, main stopcocks and often the water meters belong to the shared parts of the building. Agree any work on them, any shutdown of a whole riser and any meter replacement with the building management or owners' association beforehand. Many buildings have their own rules, such as set times for water shutdowns or a requirement to seal meters.

Replacing pipework inside a flat without touching load-bearing structures usually needs little or no formal approval, but do not assume that nothing is required. If you also plan to demolish a bathroom pod, move partition walls or make other changes, check with the local building authority whether a permit or notification is needed. Pipework should follow the relevant EN standards and local regulations, and your installer should know them.

If the kitchen work involves the gas pipe or a gas cooker, only a qualified, registered gas engineer may do it. If you smell gas, leave the flat and call the local emergency number or 112 straight away.

• Covering the pipes without a pressure test. A leaking joint then has to be found by breaking into new tiles.
• Too little fall on the waste pipes or too many bends, which leads to blockages.
• Missing insulation, so the cold water warms up and the pipes sweat.
• Mixing cheap fittings from different manufacturers that do not quite fit together.
• No separate isolation valves for individual rooms. A fault then means shutting off water to the whole flat.
• No photos of the pipe routes. Later it is easy to drill into a pipe when putting up a shelf.

Before the chases are closed and you sign off the work, check:

• The pressure test has been carried out and you have a written record of it
• You have photos or a sketch of the pipe routes in the walls and floor
• Hot and cold are clearly distinguished and hot is on the left
• Every outlet sits at the agreed position and height
• The pipes are insulated and firmly fixed
• All valves work and close fully
• Waste water drains away quickly during a test run with no gurgling
• You have a list of the materials used and the warranty terms
• The building management has confirmed the water is back on and recorded the meter readings