Water Pressure (re: Venturi Shower)

I used one of these:

screwfix sell a pressure gauge that attaches to the outside tap or washing machine tap. about £10.

The message from "John" contains these words:

No, it might be higher than 3 bar in which case your venturi shower might get overwhelmed by the cold flow. I asked when I installed a Trevi boost for my sister in their second bathroom a few years back. It might be just the manufacturer protecting their back if the pressure is not much over but I decided not to take a chance and fitted a pressure limiter in the cold supply.

FWIW everyone who has used the shower has been happy with it AFAIK but it could just be that they didn't want to upset me by saying it was crap. I haven't actually got round to using it yet as I much prefer to take a bath.

In article , Roger writes

Does anyone know what the requirement is for the water supplier as regards pressure and flow rate?

I want to put a pressurised system in the renovation property and although the pressure seems OK the flow rate is around 20l/min.

Is the water supplier required by law to provide a minimum flow rate and pressure?

Cheers

Martin

Usually 9 litre/min and 1 bar minimum.