How to prevent frozen pipes in a London home

Preventing frozen pipes is cheaper and easier than dealing with a burst. Most of it can be done in an afternoon in autumn, with foam lagging from a DIY shop and a torch. This guide is about getting ready. If your pipes have already frozen, read our guide on what to do when pipes freeze.

Why bother in London

London rarely has long hard frosts, which is exactly why homes are not ready when one arrives. In January 2026, Thames Water reminded customers to lag exposed pipes, locate their inside stop tap, note down the number of a qualified emergency plumber and check their home insurance covers frozen or burst pipes. It also said burst pipes on private property are the homeowner’s responsibility.

The Association of British Insurers said a large share of 2023’s weather related home claims came from burst pipes, most of them in the first three months of the year at the end of a cold winter.

Hackney homes and their cold spots

In Hackney, the 2021 Census found 13.9% of households in terraced houses and 15.5% in converted houses (Nomis, TS044), mostly the Victorian terraces of Stoke Newington, Clapton and De Beauvoir. These houses have the classic weak points: suspended timber ground floors with air bricks, back additions with thin walls, lofts and outside taps on rear walls. Newer blocks are less exposed, but pipes in unheated communal areas, bin stores and car parks can still freeze.

A room by room checklist

Where	What to do
Loft	Lag pipes and any cold water tank. Do not insulate directly under the tank, so a little warmth rises to it
Under suspended floors	Lag pipes that run under the boards near air bricks. Do not block the air bricks
Outside walls	Lag pipes in cupboards and boxing on outside walls, especially in kitchens and bathrooms
Outside tap	Close the inside isolation valve, open the tap to drain it, leave it open. Fit a cover
Garage or utility room	Lag pipes, keep the door closed in a frost
Boiler condensate pipe	Ask a Gas Safe registered engineer whether the outside run can be insulated or rerouted

Foam lagging should fit snugly, with joints and bends covered. Gaps at elbows and valves are where pipes freeze first.

Outside taps

Outside taps are the easiest pipes to protect and the most likely to burst. If yours has an isolation valve inside, turn it off in late autumn, open the outside tap to drain the short pipe, and leave the tap open over winter. If there is no inside valve, a plumber can fit one. It is a small job that saves a lot of trouble.

Empty flats and holidays

A flat left empty in a cold spell is the highest risk. With nobody there, a pipe can freeze, split and then leak for days during the thaw. In a block or conversion, the water goes straight into the flats below.

The Leasehold Advisory Service suggests keeping heating on a low setting if you are away during cold weather, to prevent frozen pipes. Other steps:

• Turn the stop tap off if the heating does not need mains water while you are away. Check with your boiler maker’s advice first.
• Leave a key with a neighbour or the managing agent so someone can get in.
• Ask someone to look in if the cold spell is long.
• Open loft hatches and cupboard doors where pipes run, so warm air reaches them.

If you are a landlord between tenancies, the same applies. An empty flat in January is a real risk.

Check your insurance

Thames Water advises checking that your home insurance covers damage caused by frozen or burst pipes. Some policies limit escape of water cover if a home is left unoccupied for a set number of days, or if the heating was not kept on. Read the terms before you go away for Christmas, not after.

Know your stop tap

Every guide to frozen pipes says the same thing because it matters most. If a pipe bursts, you need to stop the water fast. Find your stop tap now. Thames Water says it is usually under the kitchen sink, in an airing cupboard, under the stairs or near the front door, and recommends checking it every month. In Hackney conversions, it may be in the ground floor flat or a cellar.

When to get a plumber in

A plumber can lag awkward runs under floors and in lofts, fit isolation valves for outside taps, move pipes away from cold walls and replace old pipework that is likely to split. Our frozen pipes page explains what is involved.

If you rent, your landlord must keep the water supply installations in repair under section 11 of the Landlord and Tenant Act 1985. If you have pipes you think will freeze, raise it in autumn, in writing.