Where is my stop tap in a London flat

Everyone means to find their stop tap one day. Most people find it at the worst possible moment, with water coming through a ceiling. In a London flat, it can be harder to find than in a house, because the pipework was often added long after the building was put up.

Why it matters

The stop tap is the quickest way to stop a leak. If you can turn the water off within a minute or two, a burst pipe or a split hose becomes a mop and bucket job. If you cannot find it, water keeps coming until someone else does.

Thames Water recommends putting a monthly reminder in your calendar to check your inside stop valve is working correctly.

The usual places

Thames Water says the inside stop valve is usually located just after the water pipe enters the home. That is often:

• under the kitchen sink
• in an airing cupboard
• under the stairs
• under the floorboards
• near the front door
• in a garage, utility room, bathroom or cellar

In a flat, add a few more places to check:

• a cupboard by the front door where the meter or the electrics are
• behind a removable panel in the kitchen or bathroom
• in a riser cupboard on the landing outside the flat
• beside a hot water cylinder or boiler

Conversions in Islington

In Islington, 21.3% of households live in part of a converted or shared house, according to the 2021 Census (Nomis, TS044). In the Georgian and Victorian terraces of Barnsbury, Canonbury and Highbury, a house built for one family may now be three or four flats.

That changes where the stop tap is. The supply usually came into the house at the front, below the ground floor. So the valve for an upper flat may be:

• in the ground floor flat’s hallway or kitchen
• in a cellar vault under the pavement, reached from the lower ground floor
• in the communal hallway behind a small panel
• under the stairs in the shared entrance

Some conversions only have one valve for the whole house. If that is your building, turning it off cuts water to everyone. Thames Water notes that flats may have a communal inside stop valve where the supply enters the building, and sometimes another where the supply enters each flat.

How many stop taps does a home have?

Valve	Where	What it controls
Inside stop tap	Inside your home	Your whole supply
Communal stop valve	Where the supply enters a block or conversion	Several flats
Outside stop tap	Under a cover in the path or pavement	Your property, or several on a shared supply
Isolation valves	On pipes to toilets, basins, appliances	One fitting

The outside stop tap, Thames Water says, should only be used in an emergency, such as a leak on the supply pipe. It may need a stopcock key, and if your supply is shared, it will turn off your neighbours too. Our guide to stopcock keys and the outside stop tap explains how to use it.

How to use it

Turn the stop tap clockwise to close it. Thames Water says it may take a few turns, and a few minutes for the taps to stop running because of water left in the pipes. You should not need excessive force. To turn the water back on, turn it anticlockwise.

If it will not turn, do not force it. Old valves can snap. Our guide to a stop tap that won’t turn explains what to do instead.

Mansion blocks and new build flats

In mansion blocks, the valve for your flat is often in a riser cupboard on the landing or in the kitchen near where the pipes come through the wall. The porter may know. In new build flats, look in the utility cupboard, beside the hot water cylinder, under the kitchen sink or behind a removable panel in the bathroom. Many new homes come with a home user guide that shows where the stop valve is. If yours does, keep it somewhere you can find it.

If you rent

Ask your landlord or letting agent where the stop tap is when you move in. If they do not know, ask them to find out. Your landlord must keep the water supply installations in repair under section 11 of the Landlord and Tenant Act 1985, and a stop tap nobody can find or use is a real problem in an emergency.

If you still cannot find it

If you have looked everywhere, ask your neighbours and the managing agent. Old plans, the home information from the last sale or a previous plumber’s note may show it. If nothing turns up, a plumber can trace the supply pipe into your flat and, if needed, fit a new stop tap where you can reach it. Our stop tap help page explains what that involves.

Once you have found it, label it, tell everyone who lives with you and clear the cupboard in front of it. The next time you need it, you will need it quickly.