Installation FAQs

This page provides answers to frequently asked questions about ensuring that plumbing work is in compliance with the Water Fittings Regulations and Byelaws.

Do I need to duct or sleeve hot and cold water pipework if they are embedded in a solid floor?

Yes, you do need to duct or sleeve hot and cold pipework, to ensure the pipework is accessible and/or can be removed for maintenance or repair. For further advice please go to the WRAS website for guidance on concealed fittings.

Is it true that my flexible shower hose must not be able to reach into my WC or bidet?

Yes it is. Any shower hose that reaches into a WC or bidet bowl is a fluid category 5 risk of contamination to your drinking water supply. There are several ways to remove this problem, such as constraining the hose with a clip so that it cannot reach the WC or bidet, fitting a fixed shower screen or simply fitting a shorter hose. For further advice please visit the WRAS website.

I am installing a new water service. How deep should the trench be for water pipes?

There is a minimum and maximum depth at which service pipes should be laid:

  • Minimum depth is 750 mm
  • Maximum depth is 1350 mm.

If an installer wishes to install a service pipe either deeper or shallower than these depths they must notify the local water supplier for permission.

Important note: The gas service should be at 600mm to ensure separation from the water service pipe.

Can I build a new extension over an existing mains water supply pipe?

You should contact your water supplier, as this would prevent access for repair and maintenance. The existing mains water supply pipe will have to be either re-routed around the new extension or it will have to be installed in a duct so that it can be easily removed to allow it to be maintained or repaired.

Can I use blue MDPE polyethylene pipe above ground?

Blue MDPE pipe may be used above ground in situations where it is not exposed to light and is protected against:

  • undue warming
  • freezing 
  • potential contamination from the environment.

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