Size of water pipe?

[Orion]

I have contacted our water company, SAUR, to give a devis for a larger water pipe to supply all the future development of our buildings.We currently have a 15mm pipe supplying one house. This is a 80 metre pipe run and the pressure is moderate.

Our plans (we hope to get there one day) include in total 6 seperate properties total of 22 bedrooms and 2 swimming pools.

Has anyone any advice or comments on the optimum way to supply all the properties and the pools.

We envisage having the compteur just inside our boundary line close to the road and  then do the trenchs and  pipework ourselves. Cheaper costs of installation and abonnement?

We have in mind isues about size of supply pipe and the best way to reach all the properties hopefuly without the usage in one property affecting the pressure in another The buildings form an L shape with a pipe run of about 160 metres to the furthest house.

Is the cost of a single large diameter supply likely to be cheaper than the individual supplies by the water company to each property?

Thanks in advance

Bill (47)