New water supply to old pipe work

[FrasMac]

Hi all,

I've a bit of a situation I'm not really sure how to negotiate.

We are on private water from a well in the garden, historically the house had a gravity system and the tank in the loft space was fed by a well pump on a float switch in the tank. Looks to have been 25mm mdpe laid at some point for supply, connected into the old 28mm copper pipe to the tank.

The system was condemned on health grounds when we took on the property and we managed to get a substantial grant to upgrade the water system whereby we now have a 1000litre tank and filters in a nearby outbuilding on a pressure set with the well.
We then have supply to the house using a variable speed pump through 25mm mdpe for about ten metres before it ties into the old 28mm copper.

I'm about to redo the pipe in the house and saw some comments about there being no benefit going from 25mm MDPE to 28mm copper.

Should I stick with running 22mm through the house now?

Well have three toilets, two shower rooms and kitchen and utility sinks so not a huge amount to supply.
 

[Mr Punter]

Is this meant to be drinking water and if so, has it been tested?

 

Assuming it is fine and passes the tests are you just concerned with flow rates and pressure?

[sharpener]

If you are planning to replace the existing pipes with new copper then 22mm probably more than big enough. I was happy with fitting 22 Cu as far as the unvented cyl, though it was previously OK on a 1/2 in lead supply jointed to 15mm copper for the rising main as many Victorian houses are.

 

OTOH if you are going to use polymer pipe as easier to work with then worth keeping with 28mm as the capacity is only about 2/3 of the same OD in Cu.

 

Good calculator to play with here.

 

Would be interested to know what treatment/filration plant you have fitted in yr outbuilding.