When to Call Thames Water vs a Plumber

The two questions that decide it

Before picking up the phone, answer two things. Is it only my home, or the neighbours too? And is the problem on the street side of my outside stop valve, or on my side?

If the neighbours have the same problem, it is almost always the water company’s, whatever it is. A whole street with no water, low pressure or brown water points to the main. If it is only you, look at where the fault is. Everything from the outside stop valve, usually under a small cover in the pavement or front garden, into the house is private pipework, and that is plumber territory.

Knock on one door or check the water company’s live map of supply problems by postcode before you do anything else. It takes two minutes and saves a wasted call-out or an hour on hold. Our guide to no water in my area shows how to read that map.

Problems Thames Water deals with

Thames Water supplies water to most of London and takes waste water from nearly all of it, including homes whose drinking water comes from Affinity Water or SES Water. So for sewers and shared drains it is Thames Water across almost the whole city, even if another company sends your water bill. Thames Water publishes 0800 316 9800 as its 24-hour number for leaks, and it runs a 24/7 WhatsApp service that is handy for sending photos.

• No water, or very low pressure, affecting the street or several homes
• Water coming up through the road or pavement, or running along the gutter with no rain
• A leak at a water meter set in the pavement, or at the outside stop valve chamber
• Brown, cloudy or strange-smelling water from the cold kitchen tap, which comes straight off the main
• A drain backing up that serves more than one property, or sewage coming out of a manhole in the road
• A missing or broken cover over a water valve or sewer outside your boundary

Anything involving gas is not a water company or plumbing call. If you smell gas, open windows, turn the gas off at the meter if it is safe to, keep away from switches, and call the National Gas Emergency Service on 0800 111 999 from outside.

Problems that need a plumber

Thames Water does not work on your own supply pipe or on drains that serve only your home, even though it does look after sewers you share with neighbours. If you ring about these, you will be told to find a plumber, and that is the right answer. These are the common ones.

• A burst or leaking pipe inside the house, including under floors and inside walls
• A stopcock that will not turn, or leaks when it does
• No water in your home while the neighbours are fine
• Low pressure at one tap or one shower, or only on the hot side
• Anything to do with the boiler, radiators, hot water cylinder or immersion heater
• A toilet, sink or drain blocked where only your home is affected
• Your meter showing water flowing with every tap off, which means a leak on your side of it

The grey areas, and how to settle them

Wet ground between the pavement and your front door is the classic argument. It could be the water company’s communication pipe or your supply pipe, and the two can be close together. Report it to Thames Water first, then follow its stage on the Thames Water leak map. They will assess it, and if it is theirs you pay nothing. If it is yours, they will tell you, and Thames Water expects a leak on your side to be fixed within four weeks of it being confirmed. Who owns the water pipe to your house sets out where the line falls.

No water only at your home can also be either. The outside stop valve may have been closed by someone working in the street, or a meter may have been fitted or changed. If there has been work outside recently, call Thames Water before a plumber. If not, check your stopcock is fully open and look at no water after work in the street for the other checks.

For a blocked drain, lift the inspection chamber cover in your garden or path. If it is full and your neighbour’s is full too, report it. If yours is empty and the toilet will not flush away, the blockage is in your pipework. Thames Water blocked drain: theirs or yours has the full check.

Before you call Thames Water: what to have ready

The call is shorter and the right crew is sent if you have the details in front of you.

• Your postcode and the nearest house number or landmark to the problem
• Your account number if the report is about your own supply or bill
• A meter reading, and a second one taken 30 minutes later with nothing running, if you suspect a leak
• Photos of water in the road, a manhole or a valve chamber
• Whether anyone in the home is elderly, disabled or relies on water for medical reasons

If the supply is off for long or you are vulnerable, ask whether bottled water can be delivered. Water companies keep a register of customers who need extra help during outages.

When a plumber cannot wait for the water company

Some problems need both, but not in the order you might think. If water is pouring through a ceiling, you do not need Thames Water. Close your internal stopcock, open the hot and cold taps to drain the pipes, and switch off electrics near the water if the consumer unit is safe to reach. If the stopcock will not close, the water company’s outside stop valve can shut the supply off, but only with a stop tap key and only in an emergency.

Once the water is off, the repair is a plumbing job. Our no water emergency service covers homes where the supply has failed on the private side, and low water pressure repair covers the slow-running taps that turn out to be a partly closed valve, a failing pressure reducing valve or a furred-up supply pipe. The £60 call-out covers the visit at any hour, and the repair price is agreed with you on site before any work starts.