Plumbing regulations, FAQ
Do I need a certificate for a new bathroom? There's no single certificate like Part P for electrics, but any work must comply with Water Fittings Regulations, and gas-connected work needs a Gas Safe engineer. Can I do my own plumbing? Straightforward repairs, yes; anything affecting the public water supply (like a new connection) should go through a WaterSafe-approved plumber.
Boiler pressure and heating faults
Most combi boilers run best between 1 and 1.5 bar of pressure — too low and the heating cuts out, too high and the pressure relief valve can discharge. A plumber checking a heating fault will usually look at pressure, check for trapped air in radiators (bleeding), and check the pump and diverter valve before assuming a full boiler fault.
Plumbing emergencies — what to do first
For a burst pipe or major leak, turn off the water at the stopcock (usually under the kitchen sink or where the supply enters the property) before calling anyone — this limits water damage while you wait. For no hot water or heating, check the boiler pressure gauge first; a common cause is low pressure, which some homeowners can safely top up themselves via the filling loop.
When plumbing work needs a Gas Safe engineer instead
Plumbers can install and repair most water systems, but any work on a gas appliance or gas pipework — a boiler, a gas fire, a gas hob — is illegal for anyone who isn't on the Gas Safe Register, by law. If a job involves both plumbing and a gas connection (moving a boiler, for example), check whether your plumber is also Gas Safe registered before booking.
How long does plumbing work take?
A tap or valve replacement is usually under an hour. A full bathroom refit commonly takes 5 to 10 working days depending on scope, plus time for tiling and decorating that isn't part of the plumbing work itself. A boiler swap is typically a one-day job if it's a straightforward like-for-like replacement.
Protecting pipes in cold weather
Pipes in unheated spaces — lofts, garages, outbuildings — are the most common source of a winter burst pipe once temperatures drop below freezing for a sustained period. Lagging exposed pipework and keeping heating on a low constant setting during a cold snap, rather than off, are the two most effective preventive steps.
Hard water and your plumbing
In hard water areas, limescale builds up inside pipes, taps, showerheads and boiler heat exchangers over time, gradually reducing efficiency and flow. A plumber working in a hard water area may recommend a water softener or scale inhibitor as part of a boiler installation, particularly for a system that's expected to last 10+ years.
Combi vs system vs conventional boilers
A combi boiler heats water on demand with no separate tank, suits smaller properties with one bathroom. A system boiler uses a hot water cylinder but no cold water tank, better for higher demand. A conventional (regular) boiler uses both a cylinder and a tank, common in older properties and useful where mains pressure is poor.