When buying a property, it’s easy to check whether the taps work, flush the toilet and assume everything is fine.
But what happens when you use two plumbing fixtures at the same time?
Recently, an apartment in Fuengirola highlighted exactly why this is important.
The simple test
The toilet was flushed and allowed to refill.
While it was refilling, another tap in the apartment was turned on.
Instead of normal water flow, the water almost stopped and a loud hammering noise could be heard coming from inside the walls.
The taps worked.
The toilet worked.
But when the two systems were used together, something wasn’t right.
What is water hammer?
Water hammer is a pressure shock that can occur when water flowing through a pipe suddenly stops or changes direction.
This can cause the pipework to move or vibrate, creating a banging, knocking or hammering sound.
The noise can sometimes be caused by loose pipework, excessive water pressure, faulty valves or other problems within the plumbing system.
In this case, the loss of water flow alongside the hammering noise meant the plumbing system needed further investigation.
What could cause it?
- Excessive or unstable water pressure
- A faulty pressure-reducing valve
- A partially closed or faulty valve
- Poorly supported pipework
- A restriction somewhere in the water supply
- A problem with the building’s communal water system
The noise itself isn’t necessarily the problem — it’s a warning that something needs investigating.
What could it cost to fix?
The good news is that water hammer doesn’t necessarily mean a huge repair bill.
The cost depends entirely on what is causing the problem.
If pipework has to be accessed behind tiled walls, ceilings or fitted units, the cost can increase significantly because you may also have to pay for removal and reinstatement of the finishes.
And if the problem originates in the building’s communal plumbing system, responsibility may fall to the community of owners rather than the individual apartment owner.
These are indicative figures only. A plumber would need to diagnose the actual cause before providing a quotation.
Why buyers should test more than just the taps
A property inspection shouldn’t simply ask: “Does the tap work?”
It should ask: “What happens when the plumbing system is actually being used?”
- Try flushing a toilet while running a tap.
- Run the shower and another tap at the same time.
- Listen for unusual noises.
- Watch for changes in pressure or temperature.
- Check whether the drainage keeps up.
These simple tests can reveal problems that may not be visible during a normal walk-through.
Don’t ignore unusual noises
If you hear banging, knocking, vibrating or hammering from inside the walls, don’t automatically assume it’s normal.
It may be something simple.
But it could also indicate a pressure, valve or pipework problem that needs further investigation.
During a pre-purchase property inspection in Fuengirola or elsewhere on the Costa del Sol, unusual plumbing noises are worth recording and reporting rather than dismissing.
If you are buying a property and want the wider condition checked, see our property inspection services or contact Thermlux to discuss an inspection.
Don’t just inspect the property. Use it.
Flush the toilets. Turn on the taps. Run the shower. Test the systems together.
Because sometimes the problem you’re looking for isn’t visible on the wall.
You can hear it.