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Do I need to notify the water company before plumbing work?
Some proposed plumbing work must be notified to the local water undertaker before it starts. The exact requirement depends on the work and which nation's water fittings rules apply, so check with the undertaker rather than assuming ordinary building approval covers it.
Water Regs UK says regulation or byelaw 5 makes advance notice a legal requirement for many kinds of work on premises with a mains supply in England, Wales, Scotland and Northern Ireland. For a valid notification, it says the undertaker has 10 working days to respond and work should not start during that period.
An approved contractor may be able to self-certify some work under the local scheme, but that does not remove every notification duty. Ask for a certificate and keep it with the property records.
Notification is separate from planning permission, building regulations, electrical rules and gas safety. Any gas work remains for a Gas Safe registered engineer, even where the wider project also includes ordinary water pipework.
Contact the supplier early with a description and plan of the proposed work, who is authorising it and the plumber's details. WaterSafe says these are commonly requested. Keep the response, approved drawings and contractor certificate. If the design changes, ask whether the consent still covers it. Do not treat silence as permission until the notification is valid and the applicable response period has expired; Water Regs UK says the owner or occupier still carries the obligation to ensure the finished work complies.
For a property sale, those records can also explain what was installed, when and under whose approval scheme.
Sources
- Notification — Water Regs UK, accessed 14 November 2026.
- Gas safety: who can do the work? — HSE, accessed 14 November 2026.