Low water pressure

[DavidK3]

Hope you can help as I've not managed to find an available plumber yet.
I live in a property with low mains water pressure - measured crudely at around 10ltr/min but I'm convinced it drops below this much of the time. We cannot use our electric shower at the moment due to low pressure - been this way all winter.
We are having our bathroom and ensuite updated (hopefully) soon and would like shower(s) that take hot water from a tank as we have solar panels and want to make full use of them. The first job we had planned though was to replace the half inch/15mm copper pipe that runs from the meter to the internal stopcock with 25mm plastic pipe. We had a burst three years ago and a 2m section of the copper was replaced with plastic which is how I know what we currently have. We have a standard 15mm water meter at the roadside.
My question (at last!) is do we need to replace the supply pipe at all? It would provide peace of mind in terms of burst pipes but would it improve our water supply noticeably? I believe we will end up with an unvented cylinder (pressure vessel on top I think?), and will need a larger one than at present. Do we need a better supply just for such a cylinder?
It's just the upheaval that will be caused by digging up the garden to replace the supply pipe is a concern to me.
Thanks for any help!

 

[SJB060685]

Unvented cylinders require a minimal supply pressure and flow rate, around 2 bar pressure and 20 litres per minute. With your current arrangement I would strongly suggest upgrading the cold water main to suit. Even so one might need to consider an accumulator as well if the supply pressure is poor. This won't increase the dynamic pressure but rather maximise it to its full potential. One might consider a booster pump as well If the supply pressure is really poor, usually below 1 bar. The proper installation of unvented hot water supply requires careful consideration and should not be undertaken by someone without a full grasp of the knowledge required. I really do suggest finding a reputable firm who can undertake the work. Unfortunately this will not come cheap but with the right firm and proper execution you will get what you want.

 

[DavidK3]

Unvented cylinders require a minimal supply pressure and flow rate, around 2 bar pressure and 20 litres per minute. With your current arrangement I would strongly suggest upgrading the cold water main to suit. Even so one might need to consider an accumulator as well if the supply pressure is poor. This won't increase the dynamic pressure but rather maximise it to its full potential. One might consider a booster pump as well If the supply pressure is really poor, usually below 1 bar. The proper installation of unvented hot water supply requires careful consideration and should not be undertaken by someone without a full grasp of the knowledge required. I really do suggest finding a reputable firm who can undertake the work. Unfortunately this will not come cheap but with the right firm and proper execution you will get what you want.

Thank you. If we go with unvented we will need to change the supply pipe then - that's good news really as I was concerned we might be doing it unnecessarily. We will use a recommended plumber - not considering this a DIY job at all.
Thanks again for the reply.

 

[SJB060685]

Happy to advise and wasn't suggesting you would in any way attempt this as a DIY project. Was merely pointing out that these systems require a certain level of understanding as well as a bare minimum qualification. You would be surprised at just how many times this very subject pops up on here from homeowners such as yourself.
Any more questions feel free to ask, there is quite literally 100's of years of combined experience between us engineers on here.

 

[snowhead]

Replacing the supply pipe doesn't automatically mean digging up the whole length of the pipe, it may be just a hole each end.
Depending how the old pipe runs the new one can either be pulled in whilst pulling the old one out and new one in fixed onto it or by using a mechanical mole to create a new path for the pipe.
Using the mole depends on whether there are other services in the ground nearby.

 

[king of pipes]

I would contact your water company the minimum legal supply pressure is 1 bar pressure and to reach10 meters in height, i recently had one upgraded a 1/2 lead supply the 1/2 ferrule in the supply pipe was partially blocked we had 1 bar bud no water at 3m in the upstairs bathroom , Essex and Suffolk tapped into the main with a new 3/4 supply and fitted a new stopcock and chamber a 25 mm mdpe was taken into the property and connected into the existing , you will need a contractor for getting the new 25 mm pipe in position and valves off .kop

 

[DavidK3]

Replacing the supply pipe doesn't automatically mean digging up the whole length of the pipe, it may be just a hole each end.
Depending how the old pipe runs the new one can either be pulled in whilst pulling the old one out and new one in fixed onto it or by using a mechanical mole to create a new path for the pipe.
Using the mole depends on whether there are other services in the ground nearby.

The old pipe is copper and runs under the ensuite extension. There are also other services criss-crossing where this pipe needs to go, so I don't think we have any choice other than to dig a trench....?
We are having two bathrooms renovated, one at a time so we have one to use whilst the other is being done - we can't therefore lose the existing water supply until one new bathroom is ready to use.
Thanks for the suggestion though - never knew that was an option.

 

[DavidK3]

I would contact your water company the minimum legal supply pressure is 1 bar pressure and to reach10 meters in height, i recently had one upgraded a 1/2 lead supply the 1/2 ferrule in the supply pipe was partially blocked we had 1 bar bud no water at 3m in the upstairs bathroom , Essex and Suffolk tapped into the main with a new 3/4 supply and fitted a new stopcock and chamber a 25 mm mdpe was taken into the property and connected into the existing , you will need a contractor for getting the new 25 mm pipe in position and valves off .kop

I have emailed Anglian Water via it's customer service link on the website asking about what we need to do and if it can assist in any way. Hopefully this will get a response as I couldn't see another option for requesting advice/help.
We have called them out previously due to low pressure but all they did was spray water from the meter across our garden saying 'look, plenty of pressure here!' They didn't come into the house to check anything at all - and this was pre-covid. Our neighbours had more success as AWA agreed there must be debris or something in the pipe between the road and property. It's always been an issue here with multiple repairs being carried out to the supply pipe within a few hundred yards of us - I suspect the pressure is kept low to prevent bursts?