A weak shower does not automatically mean the property needs a larger pump. Pressure and flow are related but different, and the location and timing of the symptom matter.
Map the symptom first
Does the problem affect one outlet or the whole residence? Is it constant, or does it appear when several fixtures are used? Has anything recently changed in the property or supply? These questions narrow the investigation before parts are replaced.
A comparison between static pressure and pressure while water is flowing can help reveal a restriction that an idle reading would miss.
Check the system in order
Relevant checks may include isolation valves, strainers, filters, pressure-reducing valves, pumps, storage arrangements and signs of leakage. Where the incoming supply is suspect, measurements at the property boundary can help separate a network issue from an internal one.
In a Marbella villa with several bathrooms and outdoor taps, measuring at more than one point can show whether the issue is local to a branch or shared across the installation.
Recommend work from evidence
A pump, valve or pipe change should follow a finding, not a guess. The owner should be told what was measured, where, under which operating conditions and what those results indicate.
That approach limits unnecessary work and gives a clearer basis for any improvement to the system.