Leak on a Long Private Supply Pipe in Biggin Hill

A leak on a private supply pipe is the owner’s to fix, and where one pipe feeds several houses, it is usually the shared responsibility of everyone it serves, so check your deeds. Thames Water looks after the public main and its own connection up to roughly the boundary, not the fifty metres of pipe across gardens or a shared drive. The way to keep the cost down is to locate the leak precisely before anyone digs, then decide with the neighbours whether to repair the old pipe or give each house its own new supply.

Why Biggin Hill has so many long supply pipes

Biggin Hill grew out of the 1920s and 1930s plotlands. Land was sold off in small lots, and people built bungalows and chalets on them, often themselves. Over the following decades those houses were extended, rebuilt and joined by others, and the plumbing followed whatever route was easiest at the time.

The result, on many roads and tracks, is a house set well back from the public main, reached by a private supply pipe that can run fifty metres under a garden or a shared drive. Sometimes one pipe was laid to the first house and the next houses were teed off it. Nobody drew a plan, and nobody remembers the route.

How do I know it is the supply pipe?

The signs are the familiar ones, but on a long pipe they can be faint:

• A water bill that has jumped, or a meter that moves with everything off.
• A patch of ground that stays wet or soft, or unusually green grass in a dry spell.
• Lower pressure than usual, especially at the end of a shared run.
• A neighbour on the same pipe noticing the same thing.

Do the meter test first. Turn every tap and appliance off, read the meter, wait 30 to 60 minutes and read it again. Then turn the stopcock off and see if it still moves. On a shared pipe with one meter, every house on it needs to stop using water during the test, so agree a time with the neighbours.

Could it be ground water instead?

It could. Bromley Council’s flood risk assessment records groundwater flooding at Biggin Hill in the winter of 2014, on highways and in gardens. After a long wet winter, wet ground on a slope is not proof of a leak. The meter is: ground water does not make it move. If the meter is still and the ground is wet, it is probably the weather.

Who pays on a shared pipe?

Thames Water supplies Biggin Hill. It is clear that it looks after public pipes under roads and pavements, and that leaks within your property boundary, including the supply pipe under your garden and driveway, are yours. On a pipe shared by several houses, the responsibility is usually shared between them. How it is split depends on:

• Your deeds, which may contain an easement for the pipe and say who maintains it.
• Where the leak is. A leak on the branch to one house is normally that house’s; a leak on the common section is normally shared by everyone it serves.
• What the neighbours agree. In practice, most shared-pipe repairs are settled by agreement, splitting the cost fairly.

Thames says that once you know about a leak on your side you must fix it within four weeks, and that a metered customer who does so may be able to claim a leak allowance. On a shared supply, talk to Thames early about how that applies.

How is a leak found on fifty metres of pipe?

The first job is often finding the pipe itself. A signal sent along a metal pipe, or along a tracing cable for plastic, lets the route be marked on the ground. Then the leak is narrowed down by listening for it at the stopcocks and with a ground microphone along the route, and, for quiet leaks or plastic pipe, by filling the drained pipe with a tracer gas that rises through the soil at the leak. The aim is one hole, not a fifty-metre trench.

Repair or replace?

Once the leak is found, there are three choices:

1. Repair the one leak, if the rest of the pipe is in good condition and relatively modern.
2. Replace the whole shared pipe with new polyethylene on the same or a better route, with a proper stopcock for each house.
3. Give each house its own new supply from the main, ending the shared arrangement altogether.

Option three costs more at the start, because each house needs its own connection, which you would arrange with Thames, and its own trench. But it ends arguments about who pays, gives each house its own meter and stopcock, and usually improves pressure at the end of the run. It is worth pricing up while the ground is being opened anyway.

We agree the price with you before any work starts.

What about Thames’s main works?

Thames Water is renewing 3.9 kilometres of main in Biggin Hill, along Main Road, Leaves Green Road, Ashmore Lane and Milking Lane, with work running to September 2027. If your supply connects onto one of those roads, ask Thames what the works mean for your connection, and whether there is a sensible moment to have your side done.

Can a long pipe freeze?

A properly laid supply pipe is deep enough to stay clear of frost, but older plotland pipes are not always laid properly, especially where they come up to a stopcock or across an outbuilding. Our guide to frozen pipes on Biggin Hill’s high ground covers winter prep. Chislehurst has the same long-run problem on single big plots, and our guide to a supply pipe leak under a Chislehurst drive goes into repair and drive reinstatement. More about TN16 on our Biggin Hill page.

Need a plumber now?

If you think the supply pipe is leaking, Call 07868 281022. Tell us your postcode, whether the pipe is shared, what the meter does, and where you see wet ground. We do leak detection in Biggin Hill and water leak repairs across TN16 on the Bromley side, including Leaves Green, Downe and Keston.