Forum Topic

Misconnected sewers in Chiswick

It's a long time since I was on a building site but I can tell you it is very unlikely that anyone accidentally connects a sewer pipe into a storm drain. If Thames Water are right and one in ten properties are affected by this, then this looks like a scandal as big the one about cladding.  Slap dash sub-contractors might have done the deed but the responsibility is shared between the main contractor, Thames Water and the council, none of which seem to be inspecting these things properly. If it one in ten properties then that could mean that it is half of new builds and conversions so, if I was a leaseholder in any of those I'd be discreetly checking if I had any liability to pay to make any misconnections good.

Andrew OSullivan ● 12d39 Comments

Are you sure that TW didn't find a broken pipe at Strand on the Green?  The tide will move whatever is in the water up and down.  It's todal as far up as Teddington Weir isn't it?

Philippa Bond ● 15h

I was chatting to somebody in the building trade about this over Easter. When I told him that Thames Water had quoted a figure of 10% for misconnected properties he wasn't surprised. However he said that most of them would bye 'grey water' misconnections involving sinks, washing machines and dishwashers. Obviously not ideal but not as noxious as misconnected toilets. The stuff coming out at Strand on the Green is clearly poo, the photos in the report are all too clear and I've seen it myself when walking past. The explanation may be pre-Bazelgette Georgian properties in the area designed to flush out into the Thames.

Jeremy Parkinson ● 16h

There is no direct connection between the Tideway Tunnel and Mogden. However, the tunnel does take sewage from the Western and Chiswick low level sewers which previously went to Mogden, and now this instead goes to Beckton. This takes the pressure off Mogden and reduces storm discharges.As the Thames is tidal it isn't relevant whether you are up stream or down stream of the Tideway Tunnel, the culverts discharging sewage during storms will have polluted the water upstream of Kew Bridge so the Tideway Tunnel should have significantly improved Chiswick water quality.There is a storm discharge at Kew Transfer which is directly across the river from Hartington Road. The monitors don't seem to be working there and I don't know whether it benefits from the Tideway Tunnel or if it is still discharging. Thames Water's web site says it will be 'up to government standards' by 2040 but I would guess that as the Tideway Tunnel has increased overall system capacity, there has been a big reduction in discharges from here as well. Certainly people I know at local rowing clubs say the water is better (although far from perfect).

Mark Evans ● 1d

N V Brooks: Where is your evidence that there is a connection between Super Sewer and Mogden. None of the maps of the system show such a connection. Thesewer runs from Acton to the East and barely touches Chiswick. As far as I am aware no one has ever suggested that the Super Sewer (Tideway Tunnel) would have a significant impact on water quality from Chiswick and upstream.

Sam Hearn ● 5d

Forgot to say don't make the seed etc too oily just enough to coat it.

Janice Evans ● 5d

Any oils, fats or sunflower oil can be added to wild bird feed it's a better way to dispose of it, just add a little every time you put your bird feed out,Seeds, nuts and fruit etc., if feeding foxes add a little twice a week.

Janice Evans ● 5d

looks as though a broken pipe was found recently according to this article:https://chiswickcalendar.co.uk/sewer-flood-at-strand-on-the-green/Constant vigilance and reporting is necessary - so keep on reporting when you see anything that seems amiss.https://www.thames21.org.uk/events/It looks as though there is the famous wet wipe count coming up nearby soon... Fleur Anderson MP for Putney has battled for years to get those with plastic in them banned as they block pipes and cause damage and pollution...  but there have always been excuses.  Once upon a time there were packets which said 'Flushable' in big letters on the front of the packet and then in small writing on the back 'don't or just one at a time' on the back.  The Government agreed to ban them - so what is happening now? https://www.fleuranderson.co.uk/ban-plastic-in-wet-wipes/https://www.thames21.org.uk/events/

Philippa Bond ● 5d

"can someone explain how the construction of the supersewer could ever have been expected to clean up the water flowing past Strand on the Green"At times of excess rainfall, sewage was pumped into the river to stop the system being overwhelmed. At least one of the points of discharge was up river of Strand on the Green at Kew and that hasn't been used to pump foul water into the river since last October. This means that the water around Strand on the Green should be cleaner but it isn't.

Mark Evans ● 5d

https://www.local.gov.uk/topics/severe-weather/flooding/sustainable-drainage-systemsWe must all have all seen the terrible effects of some of the sudden heavy and/or long lasting rainfall events.  In the past many rivers were straightened for speed of transport, increase of land and ease of farming etc and now the climate is changing the emphasis is on slowing that flow so rivers are having their wiggles put back in and rain gardens and swales etc being introduced. With bigger new developments this may to the outsider just look like nice landscaping without realising the thought and work that should have gone into designing it.  With old and existing development it is much harder to know what you are going to find.  Bernard's input was interesting and shows the importance of greater knowledge, understanding and maintenance and/or updating of what is there and is happening beneath us whereas life's values sadly seem to have moved to ones of less practicality, more visual appeal and as little cost as possible.  Jim's comments on the great work of Thames 21 volunteers in championing or trying to our great River Thames reminded me of all those people who have tried (and some battles have been won) to keep so many of the things we are enticed to buy or are given and should dispose of more carefully and should not just flush out of sight or put down the drain whatever it says on the tin, bottle or packet and just because we are able.Do take a look at all the sustainable drainage systems that are being implemented worldwide and the efforts that are being made to clean up our water.  We share it with rest of the world. - whether we like it or not!

Philippa Bond ● 7d

https://www.discovereconomics.co.uk/post/has-privatisation-failedLearn something new that you may not have known!

Philippa Bond ● 8d

Hopefully with increased Environment Agency testing (reduced and/or stopped when there were so many austerity cuts) and increased public awareness it will be easier to see and tell where there is a problem to be investigated.

Philippa Bond ● 8d

Yes, I agree - but there is what is supposed to happen and what does happen with new building!  IIRC soakaways are not supposed to be within a specific specified distance from a building.

Philippa Bond ● 8d

Not all Chiswick sewage goes direct to Mogden.However the problem that has been found in Ealing and Greenford etc which has been further investigated apparently shows connections made directly to the River Crane and there are lots of hidden rivers and streams in London with Bollo Brook and Stamford Brook coming immediately to mind - together with 'ditches', springs and wells too - some of which are completely built over.

Philippa Bond ● 8d

In my experience the majority of older properties have a combined system with rain water and foul mixing in the same manhole before going into the main sewer.For many years though it has been a requirement of building regulations that rainwater from new extensions has to go into soakaways in the garden. If the garden is too small then it is permitted to discharge the water into the sewer system. I am pretty sure that on new build houses rainwater has to go into soakaways rather than the sewer system.

david ward ● 8d

https://www.cardiff.ac.uk/news/view/2797095-spilling-the-dirt-on-combined-sewer-overflowsThe above was in 2024.  It was an investigation into the problems of sewage spills and what could be done about it.  In the earlier post I accidentally failed to add that link to the quote that I took from it and repeat below:"The UK currently has one of the highest per capita water consumptions in Europe, but changes in consumer behaviour will only get us so far....."Also there is this bit of a para:"“Cost is often cited as a limiting factor when it comes to improving sewage infrastructure, but interventions that prevent combined sewer overflow spills will have long-term gains..." It is not just investment in infrastructure that is needed.

Philippa Bond ● 8d

There is a major connection from Mogden directly into the 'Super Sewer' according to Thames Water.

N V Brooks ● 8d

Good to see a really useful thread on cleaning up our local river. However can someone explain how the construction of the supersewer could ever have been expected to clean up the water flowing past Strand on the Green as stated in the original aticle? Out foul water sewage all goes to Mogden and not the super sewer.

Sam Hearn ● 8d

All well and good if the infrastructure is in place to take two discharges (surface water and waste matter). In most cases it is not and both simply merge into a single sewer. It would cost billions to dig up every road and install a seperate sewer for each. Billions that Thams Water had but chose to give to shareholders rather than invest in delivering a service. No wonder then that Londoners pay more for water then residents of, as examples, Paris, Amsterdam, Brussels and Barcelona (four picked at random from www.waternewseurope.com)

N V Brooks ● 8d

The Institute of Civil Engineers also explains ways to improve the historical situation:  https://www.ice.org.uk/news-views-insights/inside-infrastructure/why-the-sewage-problem-is-likely-to-lingerThere sre also ways that homeowners can improve the situation which has been proven by homeowners using water butts and making sure that their homes and new extensions have been and are connected in accordance with Building Regulations.  Building Regulations have to be adhered to even when building is allowed under Permitted Development.

Philippa Bond ● 9d

Here's just a part of one para: "The UK currently has one of the highest per capita water consumptions in Europe, but changes in consumer behaviour will only get us so far....."(February 2024)

Philippa Bond ● 9d

Thanks to Andrew for the initial posting on this matter. It really is a scandal and should be treated top urgently by our Council and the appropriate Authority.My own input relates to wading into the River Thames some 10 years ago when a charity called Thames 21organised a clean.up of the riverbank in Brentford.A couple of us somehow managed to reach Lot's Ait across the most vulgar mud you could imagine.Councillors ...jump on it!It is appropriate that the Boat Race organisers have raised the issue too.

Jim Lawes ● 9d

in older properties, particularly those built before comprehensive wastewater infrastructure was widely implemented, it's likely that wastewater was discharged directly into nearby rivers or streams. This practice, while no longer acceptable due to its environmental and health implications, was common in the past. Here's why and how:Limited Infrastructure:In the past, many areas lacked the advanced sewage systems and treatment plants that are now commonplace. Combined Sewers:Early sewer systems often combined both wastewater (sewage) and stormwater runoff. When the system became overwhelmed, excess water, including sewage, would be discharged directly into rivers or streams through combined sewer overflows (CSOs). Direct Outfalls:Some older properties might have had direct outfalls or connections to the river, bypassing any centralized wastewater treatment. Historical Practices:Historically, it was not uncommon for industrial and domestic wastewater to be discharged directly into rivers, without any treatment. While modern regulations and infrastructure aim to prevent such discharges, it's important to understand that older properties might retain these historical connections, especially if renovations haven't addressed the wastewater systems.

Julian Pavey ● 9d

In that case ALL connections have to be to a sewer and not the river.  This is why the Super Sewer has been constructed to massively reduce the possibility of overflow spillage into the Thames.  Unfortunately when you deregulate on a large scale you reduce the control of non-compliant drainage (fewer inspections etc).  Even surface water from roads will contaminate the river.  You can't even guarantee that someone will not park their camper van and empty their toilet tank into a surface water drain and contaminate the river.

Philippa Bond ● 9d

The problem surely is that in many areas there are not separate stormwater and foul sewers but a single pipe running under the street.No point in getting householders to make separate connections if they're all going to discharge into the same sewer.  Would cost billions to upgrade all of the sewers into two distinct systems.

N V Brooks ● 9d

These days you can't build a house not connected to a sewer but Bernard raises a very interesting point. The older properties in the area may well have been designed to discharge their waste into the river. At the time this may not have been illegal because afterall the storm drains were also being used to pump in sewage.The problem was hidden until the Super Sewer was built and now we are starting to realise it hasn't delivered the clean river that we were hoping for. It is notable that Chiswick came out with the worst readings in the tests done by River Action which could mean that we have a particular problem.The questions is now, can these older properties be forced to reconnect back into the sewerage system?

Jeremy Parkinson ● 10d

I find it hard to believe that any of these ‘misconnections’ are actually unintentional ‘mistakes’. In some established built up areas it could well be that separate drainage systems don’t exist and would be impractical to install. In bigger, new developments you’d expect this problem would be addressed at the planning and design stage, but clearly not, which one assumes can only be intentional.

Peter Evans ● 11d

Most houses of that vintage had a single surface water and waste matter discharge pip into the sewer and it worked well. The problem arose with new developments using 80-100 year old infrastructure. Short ofgetting every household to install a second separate drain and installing a second dedicated sewer to carry surface water and waste, which would cost £billions.They could start by getting the developers of some of the monstrosities being built to FULLY cover the infrstructure cost of sperated drainage.

N V Brooks ● 11d

But what are the authorities going to do with the over 100 year system that pollutes the Thames at SOTG thats the urgent problem in that area

Bernard Allen ● 11d

It most certainly is down to foul sewer systems being connected, not at the individual property level but at a muliple property site level, into the surface water drainage as has been proven at any number of developments in west London, notably a number of new builds in Ealing, Greenford and Northolt.

N V Brooks ● 11d

It had very little to do with competition at a local level but much more to do with a woeful under-delivery of service. Nothing to do with cuts as the privatisation began under a Conservative administration but continued unbated, actually gathering pace when Prescott was effectively planning supremo as Deputy Primeminister during all 13 years under Blair.We are not talking fire safety alone here but overall inept and ineffective inspection regimes which happen whether the sector is public sector or privatised.

N V Brooks ● 11d

I don’t think it’s down to miss connected sewers at all.Lots of properties were built around 1899 / 1910 in the Grove Park and strand on the green areas. A lot of the properties had a dual sewage and surface water man hole in the front of there property. They were constructed with a gully running through at low level for sewage with a non return flap fitted on the entrance to the main sewer so any back up of the main sewer didn’t flow back into the house.There was another gully running though the same man hole at a higher level the carried the surface water out though a separate system and into the river.On one job I worked on many moons ago, the non return flap or valve on the sewer pipe got stuck closed, which allowed the sewerage to back up to the height of the surface water gully and mixed in with the surface water and then the mixture flowed into the river.I wonder how many houses have that problem in that area and other parts of older London

Bernard Allen ● 11d

But we have had a period in which Building Control was privatised or part privatised in order for more competition to be introduced into the market. Some changes have happened also since Grenfell when a lot of regulation was re-visited.  It isn't just a fire safety thing.https://www.cibsejournal.com/news/privatisation-eroded-building-control-rigour-inquiry-told/

Philippa Bond ● 11d

Local Authority Building inspectors are meant to inspect new or modified drain pipes and connections to ensure they are properly installed and meet building regulations.When we had our rear extension, the inspector (a lovely guy working for Ealing who was really helpful) referred to, IIRC. "Document H" and castigated the contractor for using the 'wrong type' of connection which was swiftly replaced.

N V Brooks ● 11d

So which body is responsible for signing of on pipe connections for smaller household jobs and larger developments?

Mark Evans ● 11d

Nigel it is then. And thanks for clarifying.

Andrew Jones ● 12d

No, Andrew not the BRE but the local authority inspectors who inspect building works during progress for issues like missing wall ties, safe working methods etc and, in this particular instance, misconnected drains. Much of this work has been contracted out over the past decade.N or NV is fine but Nigel is probably better :-)

N V Brooks ● 12d

When you say "Building Control" NV, are you talking about the privitisation of the Building Research Establishment in 1997?Hope you don't mind me calling you NV by the way - but do say if you'd prefer me not to!

Andrew Jones ● 12d

The reason Building Control was largely privatised is that it was the swiftest way to deliver anything resembling a service. Woefully slow and dreadfully expensive for the 'service' they delivered.I have a good friend who owns a roofing company. His is one of very few whose consistency of quality and adherence to the rules has allowed him to self-certify his own work, subject to snap inspections which, he passes without issue.So, he self certifies which saves the householder hundreds of pounds on a replacement roof. Ealing still send building control  inspectors and then have the temerity to try and chrage the householder for 'a site inspection'. Amazing how they can do this without going anywhere near the roof!Where the current contol regime falls apart is that there is no evidence, from personal experience, of the privatised inspectors being supervised or inspected nor of them actually being available to deliver advice outside of very narrow daily windows.It is really not surprising that shoddy work gets either passed or ignored.

N V Brooks ● 12d

Although this particular article is mostly concerning the problem that occurred with cladding I think you will find that privatisation of Building Control has also caused changes and problems of checking with other aspects of construction.https://www.cibsejournal.com/news/privatisation-eroded-building-control-rigour-inquiry-told/

Philippa Bond ● 12d