Mains Water Flow - any thoughts on how to increase it?

[waran]

I was thinking of changing my conventional boiler to a combi and got a BG chap in to give me a quote.

He checked the pressure and flow in the system and said that I had a good pressure (almost 2 bar) but the flow was too low for a combi (about 6 L / min).

He measured the flow from the cold water tap in the kitchen which appears to come directly off the feed pipe to the flat. The flat is on the second floor and was probably built in the sixties. He mentioned this was a problem with older flats because they only have a single feed from the mains.

He advised me to get the water company out to check the supply which they did. They commented that although there was a small leak in the street that shouldn't affect the flow to the property. They suggested that it was an internal problem.

Interestingly having talked to my neighbours they don't seem to have a problem but I haven't yet asked them to see if I can go in and check their flow.

Any thoughts on how I can improve matters?

 

[Bahco]

Look at your incoming supply pipe.
The best pressure comes from the blue 25mm pipe which is now a requirement for all new builds.
You may find that your supply pipe is the old lead pipe or black 3/8 bore.
If so it is worth you replacing them to get a better pressure.
You can always try moaning at your water company and see if they would be kind enough to upgrade your supply pipe (free of charge of course)

 

[waran]

Thanks BAHCO,

sorry for the delay in replying.

Mine looks like the old black 3/8 bore.

I think I'll try moaning at the water company for a bit and see what happens.

Cheers for the reply.

 

[boilerbeasty]

As far as this goes, where does the water co's responsiblity end, and where does the property owners' responsiblity start ?

 

[Bahco]

Can you let me know how you get on as I would like to change my supply also. Word is that the water companys are reducing mains pressure in the next couple of years (to save money) and will have to upgrade supply pipes to customers with pressure problems.
I doubt whether they will publicise this and will only upgrade households that complain.
all the best

 

[waran]

Will do. Although knowing what they are like with non urgent problems it might take a while.

 

[Bahco]

Boilerbeasty

As we all know the water companys responsibility ends at the mains stoptap in the street, the householder being responsible for the supply pipe from their stoptap onwards.
However if a customer is unhappy with supplied pressure (which he is paying for) I believe they have a moral duty to rectify.
I am sure that out of their vast profits they can afford to help consumers enjoy a decent flow of water

 

[waran]

boiler beasty - I can only tell you what the Water chap said so don't take this as gospel.

Apparently they have a duty to supply mains water at a pressure above 1 atm and a flow above 10 l/min. But they only have to ensure that at the supply to your property. Once there their responsibility ends. He seemed to feel that if you measured at the kitchen tap then that reflected the status of the supply.

With a flat there should be individual supply to each flat but with conversions that may not necessarily be the case.

I think that most people don't really notice the difference and I must say it never occured to me that I might have a flow problem until I was thinking of replacing the boiler. Then I found out that my pressure was quite good but the flow was reduced. So it would take a while to fill the bath but the shower wasn't too bad.

Forgive me if I'm wrong but I always thought pressure and flow were related (Poiseuille's law and all that). With time, do pipes narrow thereby restricting flow but having little effect on pressure? So is it just a case of replacing the pipes with wider ones?