This is the distinction that matters, and it's easy to establish yourself.

If one fitting is weak and everything else is normal, the cause is more likely to be local to that fitting - the aerator or outlet on the tap, the shower head or hose, the isolating valve serving it, or a restriction in the pipework close to it. The rest of the property proves the incoming supply is doing its job.

If pressure has dropped across the property, the possible causes are broader: the incoming supply itself, a shared restriction, a leak somewhere in the system, or - in homes that use one - the booster pump. That's a wider investigation, not a single-fitting fix.

Depending on which of the two situations you're in, any of these may be involved:

• A clogged or restricted outlet, aerator, shower head or hose on the affected fitting.
• A partially closed valve - sometimes left that way after other work was done.
• Restrictions inside the pipework, including build-up over time.
• A leak. Water escaping somewhere in the system can show up as reduced pressure elsewhere.
• An issue with the incoming water supply to the property.
• Booster pump problems, in villas and homes that rely on a pump to deliver pressure.
• Component faults elsewhere in the system that need inspection to identify.

Symptoms alone won't separate these. A weak shower can be a two-minute fix or the visible end of something larger, and the only honest way to tell is to look.

All safe to do, and all genuinely useful to whoever attends:

• Test several fittings - kitchen tap, each bathroom, hot and cold separately. Note which are weak and which are fine.
• Check whether it affects hot water, cold water, or both. A hot-only problem points somewhere different to a whole-supply problem.
• Look at the affected outlet. A visibly blocked shower head or tap aerator is a common and simple cause.
• Note whether the change was gradual or sudden, and roughly when it started.
• Look for any signs of a leak - damp patches, unexplained wet areas, or water where it shouldn't be.
• If your home has a booster pump, note whether it sounds different or behaves differently to usual. Observe only.

Please don't dismantle a booster pump, carry out any electrical work on it, or open any part of a system that's under pressure. Those are not homeowner jobs, and the consequences of getting them wrong are disproportionate to the problem you're solving.

It's worth having looked at when:

• pressure has dropped across the whole property rather than at one fitting
• the drop was sudden and nothing obvious explains it
• you suspect a leak, or you're seeing damp you can't account for
• a booster pump is behaving differently to how it normally does
• the problem persists after cleaning or replacing the outlet on the affected fitting

If it's one fitting and the outlet was blocked, you may well have solved it without anyone visiting - which is a perfectly good result.

When the cause isn't obvious from what you can see, a visit exists to answer that question rather than to sell you a repair. The plumber establishes what's happening first; standard jobs are already priced on our plumbing services page, including booster pump servicing for homes that use one, and anything beyond that is quoted to you before it's carried out.