Water pressure and flow.

22 Nov 2019
Reaction score
United Kingdom
Any advice appreciated...

I have just had a complete replumb and new unvented cylinder and boiler installed. We only have 15mm inlet mains, but I seem to lose pressure and flow between the stop valve/outside tap and the upstairs bathroom.

I have different flow rates and pressures throughout the house. Could there be a reason for this, or has my plumber made a mistake somewhere?

As below, I checked the pressure with a meter and flow rate using a bucket, stop watch and measuring jug.

Outside tap - flow ~17 l/m (waterboard measured 20 l/m). (Pressure - 3.4 bar)
Upstairs shower (no shower head) ~10 l/m (2 bar).
Upstairs bath tap ~10 l/m.
Downstairs shower (no head) ~17 l/m.

The shower valve and tap are rated to 5 bar, so hopefully not an issue.

Any guidance would be great.
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