MDPE 32 or 25mm into the house

[seb963]

Hi,

I have just had Thames Water upgrade my mains connection to a 32mm MDPE, however my builder has run a 25mm MDPE after TW stopcock from the property boundary into the house, hence I am wondering if this would have already reduced the pressure I would have had into the house. I would have expected him to run a 32mm MDPE.
The house is now on mains pressure system (converted from gravity fed system to unvented with HW cylinder) with one bathroom, but I have the plan to add a second bathroom in the loft, and I am worried that the pressure will not be enough on the 25mm pipe. The pressure on the first floor bathroom is better than with the old gravity fed system but not exceptional.
The question is whether a 25mm is ok, or should the builder have gone for 32mm for the mains inside the house? Having paid £1100 for the TW upgrade, I want to make sure this was worth the money!
For reference the flow at the cold tap in the kitchen is about 10L/min, and reduces to 6L per min when all cold taps are opened at the same time (bath, bathroom tap, kitchen tap)

Regards

Matt

 

[Deerslayer]

It seems as if your across the pond so I'm not exactly familiar with your terms etc.
However most small and even some larger homes here have piping from street into house that has an average ID of .70" or about 18 mm, this is of course dependent on distance from street, up to 30 meters or so. It's also depending on street pressure, minimum I would put on 3/4 listed above is 55 PSI ( you'll have to convert that to metric).

I hope that helps