Leaking water supply pipe

[Bill]

Could someone offer advice on replacement of a water main.

The main is leaking under the driveway, the water company will repair for free providing the pipe is in reasonable condition. Although they won't reinstate the block paving, which seems reasonable enough. The pipe must be

60+ years old so I'd rather have it all replaced.

The existing pipe is routed from the road and down the side of the house approx 20m in length. Rather than dig up the driveway I would rather it was re-routed so it entered the house under the front door and then under the suspended floor to the kitchen at the back. This would only involve digging/moling around 6m of the drive. The under floor access isn't too bad. Are there any regs/byelaws or good practice I need to be aware off, especially with the routing under the floor and thru the external wall.

Incidentally the water company want GBP350 for the 6m bit .

Thanks

[Lobster]

I don't think there's anything specific about routing under the floor, except that the water co will need to see a drain c*ck immediately

*above* the new stopcock in the house, to allow draining down.

As regards routing through the external wall, you don't want to know. Well you do, of course, but you'll have to jump through the water co's hoops on that, so best ask yours direct. They'll send you precise specs of the depth of the hole (about 0.9m IIRC?) the type of pipe, the radius of the bend, details of insulation etc etc. If you diy they will demand to inspect your installation before sending out a crew to connect up the water (and your chances of getting it approved on 1st inspection are virtually nil, according to the jobsworth who came to look at mine!

At least you aren't coming in directly off the pavement like me, which will make life easier as you can dig a hole on the outside as well as the inside of the house (I had to dig down 1m in the living room, then go sidewise and dig through the rubble foundations until I reckoned I'd got far enough to be under the pavement so the digging crew would be able to find it when they came. Bloody nightmare, it was!)

David

[Andy Wade]

I doubt that that would be acceptable, running the pipe through an unheated space where there's a risk of freezing. Usually water co's want the service pipe buried to a min. depth of 750 mm and to rise directly to the stop c*ck. Ask them about this before going any further, they're usually only too glad to give advice.

With (future) mains-pressure hot-water systems in mind and the trend away from storage cisterns, it's becoming usual to use 25 mm (o/d) MDPE pipe for the service, rather than the 20 mm that used to be standard.

Consider whether to have a water meter fitted at the same time, if you haven't one already.

After fitting the new main stop c*ck and connecting the new service, check that the electrical main earth bonding connection is still in place, connected to the copper pipework just above the stop c*ck.

[Christian McArdle]

I believe you will need an accessible stopcock where it enters the underfloor space. You might have to loop up above the floorboards to make the stopcock accessible. Use at least 25mm MDPE, preferably 30mm to the stopcock. MDPE is not intended for use in houses unprotected after the stopcock.

So run from the stopcock to the kitchen using PEX pipe, very well lagged, using at least 22mm diameter. If you live in a particularly cold part of the world or the house is left unoccupied for periods in winter, consider using thermostatically controlled heat tape to avoid freezing. When used on PEX pipe, you normally need an extra layer of aluminium tape underneath the heat tape to spread the heat. Remember that you still need to lag. Use the thickest stuff you can find, as it will further prevent freezing and will save energy on the heat tape.

Christian.