Pre-Planning and future proofing water mains

[RDTLlan]

Greetings all. I am starting a new farm on some land which is 100m away from the water mains. What size diameter pipe of MDPE should I plan for? 25mm or 32mm? Initially I have permission for a caravan, which Im sure 25mm will do fine, however when it comes to building a new house I dont want to rip up the 25mm if a 32mm is needed, so I want to future proof the water supply.

The farm itself wont need much additional water, so just average domestic use. The new build wont be too big, a simple two bed most probably with a max 2 bathrooms. My only concern is the distance.

Water company has quoted £1,400 for a connection to the mains using 25mm, and £1,700 for a 32mm connection. The cost of the MDPE is not an issue, but the £300 difference in connection is a big jump!

Any advice on what size MDPE will be appreciated.

Thanks RDT

 

[snowhead]

32mm from house to 1mtr short of mains.
Reduce to 25mm for connection.

Future proofing on a budget.

 

[lame plumber]

brilliant lateral thinking there

 

[tamz]

Stick a 63 in just incase your kids want to sell off plots :smile:

 

[RDTLlan]

Thanks for that guys. I do have one more question: If a 32mm pipe is used from house (caravan for now) to 1m short of the mains, would the 25mm connection from the mains reduce pressure/flow? Would the flow/pressure be as good as its weakest link, in the reduction of 32 to 25? Sadly the last time i did any kind of physics was in school quite some time ago, so I am very sketchy on flow/pressure considerations. Welsh Water are apparently not in a position to help so Im turning to you gents.

 

[lame plumber]

i think the indication was to run the last couple of metres in 25mm to the meter to cop a smaller bill, once installed pop it back to 32mm, just needs a new connector to meter end, cheeky ploy thats all

 

[RDTLlan]

Thanks for that Lame Plumber. Am I correct in thinking then that from the mains to the meter is a standard gauge suitable for use on either 25mm or 32mm pipe? And should 32mm be connected from the meter to the rest of the land, there will be no difference in pressure/flow if using a '25mm' connection from mains to meter?

 

[lame plumber]

a large bore mains will have a meterattached to it so if you then use 25mm mdpe it will have less flow available than 32mm due to resistance of the pipe bore etc, so for a better flow have it all in 32mm, but if you had a tail of 25mm to the meter it would bew easy to reconfigure to 32mm at any time, especially as back filling your trench is your responsibility. you would need an approved plumber to do the work or the water provider would spot your ploy

 

[RDTLlan]

Many thanks for that lame plumber, very helpful.

 

[Joncpi]

Your local Water Authority are probably quoting you for either a 1/2" or a 3/4" meter. Or just possibly a 3/4" or 1" meter that is why there is a difference in cost. As long as the pipe is laid to their specs they are not really interested in what size it is. The other point to bear in mind is that the bigger the meter the larger the annual standing charge. Off the top of my head I can not remember exactly the flow rate through each meter but a standard 1/2" meter will allow a lot of water through it. So unless you are going to have an exceptionally high demand then I would go for the 1/2" meter it is the cheapest. You can always upgrade later if you have to but it's unlikely. You can ask the Water Co for the flow rates. Or probably look them up on line. Then make your decision. Also the flow rate does depend on the available pressure in the main. The Water Co is only obliged to provide 0.8 bar but most will guarantee a minimum of 1.0 bar. Check your pressure.

 

[RDTLlan]

Thank you Joncpi, very informative. I think a 1/2" meter it will be and lay 32mm MDPE. Thanks to all!