Mains water supply safe distance below ground?

[friend of stouby]

Hello to all

The rear wall of our fermette has soil against it to a maximum depth of about a meter as the house is built on a shallow hillside. Next spring we will remove the soil against the rear wall down to internal floor level and create some form of land drainage maybe 3 or 4 meters away from the rear wall.

The mains water pipe runs across a field and into our house at or just below floor level. We do have the occassional -15oC cold snap we are told.

The question is...  as the mains pipe is presently at least a meter below ground there doesn't appear to be a freezing problem, but if the pipe where it enters the house is only 10 or 20cm below the new ground level when the soil is removed, it occurs there maybe a problem. Has anybody overcome this problem before or have any practical solutions? I understand it may be necessary to ask for the pipe to be sited deeper, but am trying to avoid going that route if possible. Is there a know minimum depth that water pipe should be placed below ground level?

 

Sorry for such an obscure question and thanks in advance

Jamie

 

[Gluestick]

Well, just had a new water main fitted: the pipe into the house (synthetic, to replace the very old lead!) is only about nine inches under the soil surface, 'cos that's where it emerges in the house, just under the floor.

Since the old lead pipe was buried to the same level (I watched the guy dig it out), and hasn't frozen thus far I suppose this must be OK?

We'll know when Winter finally comes!

 

[Wozza]

Jamie

We did exactly what you have described to our house in Wales - dug out the back and installed land drainage. This exposed both the water and the oil pipes leading to the house (water pipe was MDPE black plastic). We insulated the water pipe and buried it about 300mm and it never froze.

Ironically, the oil pipe did - a bit of water/condensation from the tank got into the pipe, and being heavier than water came to rest at the lowest point of the pipe. As the pipe wasn't insulated, the water froze, blocking the oil supply. Took ages and many plumbers visits to figure that one out! Not really relevant, but maybe of interest to someone out there!

Warren

[Gastines]

Apart fromthe freezing aspect, one of the reasons most supply pipes are down about a metre is for Safety!! If you are only going to have a very shallow soil cover, you would do well to cover the backfill with a blue [for water ] plastic film which is supplied in rolls about300mm wide. As your pipe is going to be so near the surface,it may help if you put a layer of Jablite ,or similar, over it.

Having had a supply pipe in our front yard freeze, I did manage to thaw it out by parking the car over it with the engine running and after about an hour of shunting up and down ,it worked.

If you dug the required trench and put in a new pipe, you could save yourself years of problems and worry.

Regards. 5 mins St.Malo

[Chancer]

I believe that the normes in my departement are minimum 80cms beneath the surface.

[friend of stouby]

... the reason for not wanting to disconnect the supply and sink the pipe deeper is mainly due to the supply arriving through the neighbours garden and so far we haven't found any form of external stop-cock, although very thoughtfully we have them either side of the meter that is located inside the kitchen.  

[friend of stouby]

.. interesting piece of censorship in the former mail !

[Jc]

Probably because of thr hyphen-might work as one word.