External stopcock on the street

Pincher

I am migrating from a vented system to mains water pressure.
I was told I need a new bigger external stopcock to get really good mains pressure, plus 22mm blue plastic pipe to bring it into the house.

We had lead pipework from the pavement into the house, which I changed to 22mm blue pipe from the pavement to the kitchen.
The mole would have been £1,000, so we physically dug the drive and pavement up and recovered it for £600. We are not allowed to change the external stopcock (a valve), because it belongs to Thames Water.
The pin that turns the valve had badly rotted away, and we had to replace it while it was accessible. I tried to get Thames Water to replace the valve at the same time, but they wanted £1,000 , so we put the earth back, and re-covered. They claim to have put me on a waiting list for free "infrastructure renewal", and that was two years ago.

The pressure is pretty good as far as I can tell, and is definitely stronger than with the lead pipe. So I am wondering whether changing the external stopcock is just a myth. I am about to do the two bathrooms on the first floor, and need to decide whether the mains pressure will be good enough for the showers.

So my question is: If I measure the pressure at the first tap into the house (in the garage), what is the minimum pressure I should read for a good shower head pressure on the first floor, assuming 22mm distribution pipework. I have been badgering the plumber to measure the pressure for two years, every time he turns up to do some work, but he never has the pressure meter with him. I am probably going to buy one myself, but it seems pointless if I don't know what pressure I need. Is two bar good enough if only one shower is running at a time?

Otherwise I need to install pumps until Thames Water upgrades the external stopcock.

uncovered

increasing the pipe size of your supply will not increase the pressure, it will only increase the flow.

you could put a 63mm main into your house but you will still only get the pressure which is inside the main. Every property in your street will have the same pressure. But the pipework into the propertys are different, hence everybody will get different flow rates depending on the conditions of the comm pipes and supply pipes.

I would say you should be more interested in your flow rate. If you have renewed you supply pipe to the boundary you may have noticed an increase in the flow rate, but with the Water Companies communication pipe still being lead then you will not be getting the greatest benefit.

I couldn't answer your question on the shower heads, I don't do internal stuff.

lapat

if you had lead in your garden to your property. thames will have lead in the street. ask for a lead sample to be taken if it fails there specified limit they will replace it rapid from the street to your new blue poly.

lapat

also just on a quick note there lead could also be causing your poor supply restriction so ask for a pressure and flow test aswell whilst there doing the sample and if its below there specified limits ask them to replace there side from the main to your boundary.