TL;DR
Much of the period housing in Fulham and Battersea is large Victorian or Edwardian houses built for one family. Owners later converted them into two, three or more self-contained flats. The drain underneath was usually not upgraded to match. It is often still the single pipe that served one kitchen and one bathroom. It now carries waste from several of each.
When that shared run blocks, every flat on it loses its drain at the same time, because they all share it. That is why converted homes in these areas see more repeat blockages than a similar house in single occupation. If a shared drain keeps backing up, request a quote online for a CCTV survey. It shows exactly where the blockage sits, and which section of pipe it is in.
One Pipe, Several Households
Walk down almost any residential street in Fulham or Battersea and the pattern repeats. A tall period house, once a single family home, now has three doorbells and three flats. If you are in SW11 or SW8, our page on blocked drains in Battersea covers who looks after shared and private drains locally.
This is one of the most common conversions in this part of south-west London, since it makes good use of large homes. It makes good use of homes that would otherwise be too large for most modern households.
In most cases, the drainage below ground does not change during the conversion, because the work is costly. The original drain carries wastewater from the property to the public sewer. Builders sized and laid it for one kitchen, one bathroom and maybe a scullery. After conversion, the same pipe is often the only way out for two or three kitchens and bathrooms, so the load has doubled or more.
Why These Runs Block More Often
More outlets feeding one pipe means more chances for the usual causes of blockage, since each flat adds waste. Fat and food debris come from several kitchens. Wet wipes and hygiene products come from several bathrooms.
All of it meets in a pipe that was never sized for that volume. A single household might get away with a bad habit at the sink, yet three flats cannot. Multiply that across three flats on one run, and the pipe reaches its limit far sooner.
A shared run in an older conversion often has awkward bends and junctions as well, because of past alterations. Builders added junctions whenever a bathroom grew or moved. They also joined sections of different ages and materials over the years.
Every junction and every change of gradient is a place where debris can catch, while straight runs stay clear. That is one reason these shared runs need clearing more often than a simple single-occupancy drain.
Whose Drain Is It, Anyway?
Responsibility for shared drains changed for many London properties in October 2011, although the change is not well known. Many shared private drains and sewers passed to the local water company. Broadly, the pipe that serves only your own flat usually stays private. A shared drain that serves more than one property is more likely to belong to Thames Water now.
Thames Water is the sewerage undertaker for the area. Where the boundary falls depends on the layout of each property. That is another reason to get a proper survey, not a guess, before anyone agrees to pay for a repair.
This is a common source of friction in converted homes, because several parties share one pipe. The freeholder, the leaseholders and the water company may all have a stake in one length of pipe. Nobody wants to pay for a repair on a section that turns out to be someone else's. Without evidence of where the fault sits, that talk tends to stall.
Finding the Blockage Before Arguing About Whose Job It Is
Before any of that gets sorted, the first practical step is the same either way, since you need facts. Find out exactly where the blockage is and what causes it. A CCTV drain survey traces the run from the property boundary to the sewer connection.
The footage shows which section has the blockage. It shows whether the cause is a build-up of debris or a structural defect. It also shows where the fault sits relative to the boundary between private and shared responsibility.
For a repeat blocked drain in a converted flat, that footage often settles who arranges the repair, since it shows the fault. It also stops the same section blocking again a few months later, because the real cause has been found.
Keep a copy of the report on file once the immediate blockage is dealt with, because it saves time later. A building with several households on one shared run benefits from a record of the pipe's weak points. The next problem, if there is one, takes far less time to solve. You will not have to start the whole investigation from scratch.
FAQs
Why does our drain block more than the flat we lived in before? Suppose the old home was a single-occupancy house, and the new one is a converted flat that shares a drain, which is a big difference. The answer is often volume. More households mean more waste, on a pipe that was not upsized for the conversion.
Do all the flats on a shared drain have to agree before it's fixed? In practice, whoever finds the blockage usually needs to arrange access. Depending on where the fault sits, they may need to work with the freeholder, the managing agent or other leaseholders on the same run. A survey report that shows exactly where the fault is makes that talk much easier.
Can a CCTV survey tell us if the drain is private or Thames Water's responsibility? A survey shows the layout and condition of the pipe. That is the key evidence for working out where a fault sits relative to the private and shared boundary. However, the final answer can also depend on the transfer records for the property.
Sort a Shared Blockage Before It Recurs
If a shared drain in a converted Fulham or Battersea flat keeps backing up, get the run mapped before you book any repair. Get in touch online to arrange a CCTV drain survey. The same shared-drain pattern shows up right across this stretch of south-west London.
It runs from Fulham through to Battersea a little further along the river. Our page on blocked drains in Fulham explains who looks after shared and private drains in SW6.
Because every property is different, start with our guides to blocked drains and kitchen drain blockages advice. We also cover blocked drains in Fulham and blocked drains in Battersea, so you can see how the work runs near you.
