Why the water pressure is bad on the top floor

If you live on the top floor of a Cyprus apartment block, the shower is probably weak. It is the single most common thing people ask us about, and most of the time nothing is broken at all.

Where your water actually comes from

Almost every apartment block in Cyprus is plumbed the same way, because the district rules require it. Water comes off the street into a tank at ground level, a pump lifts it to the roof, and from there it feeds down to the flats by gravity. Each flat has its own tank up there, usually at least 800 litres.

So your shower is not fed by the street pressure. It is fed by a tank sitting a few metres above your head.

Why height is the whole story

The push behind your shower comes from one thing: how far the water falls to get there. The further it falls, the harder it comes out.

Now think about where you are. The tank is on the roof and your shower head is maybe two metres below the water in it. A flat three floors down is more like twelve metres below the same tank. Six times the drop, six times the push. Same building, same water.

That is why the top floor is always the worst. It is not last in the queue. It is nearest the tank, and nearest means weakest.

Two things follow from that, and both surprise people:

• It gets worse as the tank empties. The push comes from the height of the water surface, not the bottom of the tank. A half-empty tank can take a third off an already weak shower.
• Turning up the heat does nothing. Hot and cold both come from the same roof tank, so both are equally weak.

What to check before buying a pump

A booster pump is sometimes the right answer. It is also the expensive answer, and there are four cheaper things that cause the same symptom. Any plumber should rule these out first:

1. The aerator — the little screw-on mesh at the tip of the tap. They block with grit from the tank. Unscrew it and rinse it. This is free and it fixes it more often than you would think.
2. The strainers in the mixer — most shower mixers have small filters at the inlets, and they clog with the same grit. This is ordinary tap and mixer work, not a big job.
3. A part-closed service valve — the small isolating valve under the sink or behind the toilet. If someone has worked on it, it may never have been reopened fully.
4. The flexible tail — a kinked or crushed hose behind the unit chokes the flow on its own.

If all four are clear and it is still weak, then the push really is the problem, and a pump is a fair conversation to have.

The trap when you replace a shower

Most modern shower valves — the kind with one lever that holds the temperature steady — are built for homes with mains pressure. They need several times more push than a top-floor Cyprus flat has. Fit one of those up here and it will run cold, run hot, or barely run at all.

There is a low pressure version of exactly the same thing, made to work on a tank like yours. If you are buying a new shower, ask for that one.

It is not an upgrade and it does not cost more. It is just the right one for the building. Most people only find out after they have fitted the wrong one.

What we will tell you

If you call us about weak pressure on a top floor, the first thing we will do is ask which floor you are on and how old the shower fitting is. Quite often the honest answer is that the building is doing exactly what it was designed to do, and the fix is a five-minute clean rather than a pump on the roof.