No water: what to check before calling Thames Water or a plumber

Turning on a tap and getting nothing is alarming, but the cause is usually one of three things: a problem on Thames Water’s network, a problem with your building’s system, or a problem in your own pipework. Working out which saves time, and saves you paying a plumber for a fault that is not yours.

Step 1: is it the street?

Ask a neighbour, or check a flat on a different floor of your building.

• If the whole street has no water, it is almost certainly a burst main or planned work. Check Thames Water’s view and report problems page or call its customer care team on 0800 316 9800, which its complaints page says is available 24 hours a day.
• If you live in a block, ask someone in a different block or a house nearby. If they have water, the problem is your building.

If it is a Thames Water problem, there is nothing for a plumber to fix yet. Keep a tap turned off rather than open, so you do not flood a sink when the water comes back.

Step 2: is it the building?

In a block, cold water usually comes up a rising main. In taller buildings, mains pressure alone cannot reach the top floors, so a booster pump or a tank does the job.

What you notice	Likely cause
Top floors have no water, lower floors are fine	Booster pump or tank problem
Whole building has no water, street is fine	Main valve closed, pump failure or a burst on the building’s supply
Water comes and goes on upper floors	Pump cycling or tank refilling slowly
Hot water is fine but cold is off	Separate cold supply valve closed

These are the building’s systems, not yours. Call the concierge, managing agent or housing provider. The Leasehold Advisory Service says the freeholder is usually responsible for communal pipes and tanks that serve more than one flat.

Tower blocks in Tower Hamlets

In Tower Hamlets, 80.7% of households live in purpose built flats, according to the 2021 Census (Nomis, TS044). That is the highest share of the boroughs we cover, and includes the towers of Canary Wharf and the Isle of Dogs as well as large estates in Poplar, Bow and Bethnal Green. When water goes off in these buildings, the cause is often a pump, a tank or a valve in a plant room, and the fix is the building’s.

If you are on an upper floor, ask a neighbour a few floors down before you do anything else. If they have water and you do not, tell the building management straight away.

Step 3: is it your home?

If the street and the building have water and you do not, the problem is in your pipework.

1. Check your stop tap is open. It may have been closed by a plumber, a contractor or a previous tenant. Thames Water says to turn it anticlockwise to open, and that it can take a few minutes for water to reach the taps.
2. Check for a second valve. Flats may have a communal valve where the supply enters the building and another where it enters the flat.
3. Check isolation valves under the sink or near the boiler. If only one tap is dry, it may be a closed isolation valve.
4. Think about the weather. In a cold snap, a frozen pipe in a loft, a cupboard on an outside wall or under the floor can stop the supply. Our guide to frozen pipes explains how to thaw them safely.
5. Look for a leak. A burst you have not found yet can drop the pressure to nothing.

If none of these explain it, call a plumber. Our no water or no hot water page explains what a visit involves.

After the water comes back

Thames Water’s after an incident guidance says:

• pressure can take several hours to return, longer at the top of a hill
• water may splutter at first and should clear if you run the tap for a couple of minutes
• cloudy or milky water is usually tiny air bubbles and should clear
• brown or orange water is usually disturbed deposits. If neighbours have it too, contact Thames Water. If only you do, contact a plumber
• if your neighbours’ water is back and yours is not, you may have an airlock, and Thames Water asks you to call 0800 316 9800

If you rent

If the problem is in your home or building, tell your landlord or housing provider. Under section 11 of the Landlord and Tenant Act 1985, landlords must keep the installations for the supply of water in repair and proper working order. Put it in writing and keep a copy. If someone in the home is vulnerable and has no water, say so clearly when you report it.