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Andy B · Joined: 02 Jun 2008 Posts: 3 Location: Devon

I'm renovating a 1903 mid-terraced 2 bed house. Whilst I have the floors up to allow the electrician to work I'd like to replace the water supply pipe(currently lead).

1. What diameter of MDPE should I use? the run from meter to sink is about 10m.

2. How should it be supported under a suspended timber floor?

3. When it passes through a wall, will it need a conduit?

4. To what standard should it be insulated?

5. I believe that the outside trench should be between 750mm and 1350mm in depth and that the pipe must remain at that depth internally for 750mm beyond the property exterior wall. is that correct?

6. Will the water board want to inspect the work before connecting to the meter?

Thank you in advance for your advice.

thescruff · Moderator Joined: 03 May 2003 Posts: 4605 Location: Bath

1. As big as you like, 25mm is normal 32mm for 2 or more bathrooms.

2. yes or dig a 12" trench and cover it up, assuming the floor is not concrete.

3. Yes and sealed on the ends, expanding foam is good.

4. 25mm minimum unless, see 2.

5. Thats correct and the pipe is laid on and covered with sand.

6. The water board will want to inspect, and you should notify them before you start.

Some water authorities have a free lead replacement program if you do the dig.