I am in the process of renovating my 150 year old house, which
includes fitting a new plumbing system.
A steel water supply pipe (¾"?) runs in a straight line from the water
meter at the boundary of the property, under a garage, up the garden
and into the house - a total distance of 35m. The depth of the pipe
under the ground is only 25-50cm. The pipe looks old and corroded,
although the water from the tap looks clear. There is no evidence of
leaking. The water pressure doesn't "feel" high but Cambridge Water
measured it at 2.8 bar (mid-morning).
Another point: I plan to install a new, unvented, mains-pressure hot
I am considering whether it is worth replacing the steel water supply
pipe with a blue polythene pipe. My options seem to be:
1. Leave the steel pipe where it is and run the new plumbing off that.
2. Replace all the steel pipe with blue MDPE pipe and hire a moling
equipment contractor to tunnel the 5.5m distance under the garage.
3. Run blue MDPE pipe from the meter and then around the perimeter of
the garage (adds three bends of 2m radius) and then straight up the
garden to the house. Total pipe length = 45m.
Option 1 might result in frozen underground pipes, greater probability
of leaks and lower pressures. Option 2 looks expensive. Option 3
introduces pipe bends and a longer run.
Which is best, do you think? Are there any other practical options
What's "best", 25mm or 32mm blue plastic pipe?
Supplementary question: Is it OK to tee off the supply pipe half way
up the garden to a stand pipe to be used for watering the plants? Or
should I run a pipe from the house back to garden stand pipe instead?
Thanks in advance for your advice.