Doesn’t sound all that terribly sensible

Developers must install rainwater toilets when building new homes to stop river pollution, campaigners have said.

Britain’s Victorian water system is already struggling to cope, with sewer systems frequently overflowing, making England’s rivers the dirtiest in Europe.

Now there are calls for tougher restrictions on developers, limiting their ability to connect new homes to sewers and requiring new homes to meet water efficiency standards.

Water companies can dump raw sewage in rivers and the sea when rainfall mixed with waste water from households overloads the system, something which is only supposed to happen on rare occasions but in practice happened 400,000 times last year.

Campaigners said measures such as reusing rainfall to flush toilets as standard, reducing the volume of water going into sewers, would stop the system becoming overloaded.

The system works by capturing rainwater and filtering it into a tank where it is kept at a suitable temperature to avoid bacteria. The water is then pumped through the plumbing system when a toilet is flushed.

By diverting rainwater from sewer systems into household plumbing, sewers become less overwhelmed, decreasing the likelihood of river pollution.

Bit Heath Robinson. Every house now has to have an additional system.

Why not just build out the central sewer system a bit more?

And wouldn’t it be nice to see the proper costings on this?

BTW, doesn’t the water company own all the rainfall anyway?

32 thoughts on “Doesn’t sound all that terribly sensible”

  1. They’re joking aren’t they? You’re talking about a couple of litres a flush. Wouldn’t even dampen the floor of a sewer.
    As for “The system works by capturing rainwater and filtering it into a tank where it is kept at a suitable temperature to avoid bacteria. ” What a strange, ridiculously expensive way of dealing with a common problem. One tablet of chlorine or bromine pool steriliser. Would last months. We use it in our outside jacuzzi. I also put small pieces in the water trays the plant pots stand in. Stops mosquitoes breeding in them.

  2. Bloke in North Korea (Germany province)

    bis, it is nothing about solving a problem.

    Along with insulation, mandatory photovoltaics, and the 1001 other “cost more than they are worth” green mandates, it is about making owning property so expensive that not only will you no longer want to, you will end up begging and pleading with Klaus to come and take it off your hands. By owning nothing you will become happy.

  3. This proposal would not reduce the amount of sewage by one litre. It may, I suppose reduce the need for water supply, but that is not the stated problem.
    It would be far better to address the actual problem- surface water drainage getting into the foul system and overloading it.
    So accelerate the program to separate surface water drainage from foul.

  4. Just over 10 years ago, I was planning to demolish our old (Edwardian) house and replace it with two new energy efficient ones. For a while I subscribed to a green architecture magazine. It published an article on the carbon economics of rain water storage which concluded that the greenest option was to forget rain water storage and use mains water.

    There is an enormous carbon cost of installing a significant rain water storage tank. It’s mostly due to the heavy concrete jacket that is required to prevent a less than full tank from floating out of the ground when the ground is wet. Rain water from an underground tank has to be (electrically) pumped up into the tank which serves the second water system in the house. Taking carbon costs over a reasonable lifetime of operation, a rain water system will never break even. According to the article. In a publication advocating green architecture.

  5. Incidentally, if you really wanted to alleviate this problem, disconnect your sewage system from the main sewers & run it through what I bought for the French house rather than installing a new fosse. Cost me 3 1/2 thou & uses a 100W when it’s running. What comes out the end you could almost drink. Just put it down a soakaway in the garden, keep your land irrigated. And discontinue paying the sewerage part of your water bill. Pay for itself in a few years.

  6. Capturing rainwater for flushing toilets is a stupid effort for very very little gain. Keeping separate surface water drainage from foul is a great idea. That’s why we have been doing it on builds since the 1950’s. You even get a waste water bill rebate if you let them know that you aren’t discharging surface water into the foul drain.

  7. “This proposal would not reduce the amount of sewage by one litre”

    Well, it might, diverting surface water to sewer path via the toilet flush, presumably eliminates the potable water that would otherwise have followed that route

    However, it’s still boneheaded for all the reasons others have pointed out above. Plus ‘kept at a temperature’ implies energy consumption, no ?

  8. So many things wrong with this. It costs money to keep a reservoir above 65C (recommended against Legionaire’s). No one is going to drink from the toilet bowl. Shit contains microbes. Droughts happen.
    It seems a bit much to treat rainwater like waste. Sure there’s some contamination from tyre rubber, spillages, etc but the concentrations must be small. Now if there was only a way to divert excess rainwater, with its more diluted contaminents, into the rivers; while keeping the sewage in the system.

  9. “Keeping separate surface water drainage from foul is a great idea. That’s why we have been doing it on builds since the 1950’s. ”
    Victorian/Edwardian London was built with dual sewage systems. It’s not when they started doing it, it’s when they stopped doing it.

  10. But, but, but…

    The Remoaners insisted that EU membership meant that the UK had crystal clean rivers and beaches… And now we learn that England has the dirtiest rivers in Europe…

    They couldn’t have lied to us could they…?

  11. For N years there has been the option to save rainwater in a tub in order to use it to water the garden during dry weather (for n, where n<<N, years we've used it). This does more to cure the reported problem than the proposal which prompts the question "how do you flush the toilet during a hot, dry spell of weather).

  12. Where I used to live in France the local water board helpfully gave a breakdown of their costs and hence my bills. 10% of the cost was for supply and 90% was for waste treatment. (Hence a water butt saves a fortune.A grey water system – using waste from washing machines, bathing, etc – to flush the toilet would also have a short time to payback.) I’d hazard a guess that the balance is roughly the same in the UK.

  13. View from the Solent

    My water supply and removal are done by separate companies. From memory, the removal cost is around 4-5 times the cost of supply. So still significant.

  14. Bloke in North Dorset

    How big are these tanks? The problem they’re trying to alleviate occurs during heavy down pours or during long periods of constant rain. Once they’re full, and it won’t take long, the overflow is going in to the sewers as if nothing had happened.

  15. Hang on a minute… Whether the rainwater gets into the sewers by direct runoff or by a delayed route via the bog, it still gets there. I don’t see how this idea would reduce the amount of rainwater going into the sewers by so much as a teaspoonful, just the timing thereof.

  16. Incidentally, if you really wanted to alleviate this problem, disconnect your sewage system from the main sewers & run it through what I bought for the French house rather than installing a new fosse. Cost me 3 1/2 thou & uses a 100W when it’s running. What comes out the end you could almost drink.

    What happens to the non-liquid elements?

  17. To emphasise. If you continue to flush at the same rate as before, it matters not whether you flush with rainwater, water from your own well, or tap water. The same amount of water reaches the foul sewer.
    Flushing with grey water would help, as that would have gone down the foul sewer anyway. I don’t see that being very popular though- grey water is dirty and smelly, just not so much as other foul sewage.

  18. I use rainwater for flushing, but the motivation was saving money, not relieving pressure on the sewage system. After all, it still all goes down the same sewer whether it’s run stright off the roof or it’s gone through the toilet.

    Also it just seems so wrong to take water that’s gone through all that treatment to make it drinkable and just chuck it down the loo.

    When I lived in Hong Kong we had a seperate ‘potable’ and ‘non-potable’ supply, the latter used for flushing. Seems eminently sensible.

  19. Addessing the points raised earlier:
    It’s a bog standard cold water header tank in the roof just below the gutters fed by a pipe from the rainwater downpipe, with an overflow back into the normal drain.
    It’s stays at the fairly stable temperature of being inside the roof.
    There is never enough static water for nasties to build up, after all it’s being run off every day to flush the toilet.
    If it every runs dry, there’s a bypass tap near the ceiling in the bathroom to fill it from mains water. If I coulbe be arsed I’d work out an automatic system.

  20. And how many homes have gardens or land large enough to take tanks that will make a difference and won’t run out after a few flushes?

    Like Greeny demands that every house have solar panels, they don’t think about reality. Like not all homes have south facing roofs to make it worthwhile.

  21. @Pat

    The same amount of rainwater reaches the sewer, yes, but the amount of [previously] potable water doing so is reduced by the amount of rainwater now passing via flushing instead, thus the total water reaching the sewer is reduced

    Doesn’t make it a sane idea overall though…

  22. On the accusation of it being a Heath Robinson system, it’s really a matter of perspective. Putting all your eggs in one centralised basket might be cheaper overall, but it’s also more fragile. Look at how many companies in California have installed their own generators for every time the power goes out.

    If you believe that Britain (or wherever you live) is suffering a steady decline of technical competence, you’d be wise to have a house full of contraptions – assuming that you’re capable of maintaining them yourself.

  23. Thames Water charge about 90p per cubic metre of waste water. About £1.50 for supply.

    A 1,000 litre water butt will cost about 300 quid.

    Yer average bog is probably about 5 litres, so 200 flushes per cubic metre, so each flush is 1.2p in supply and waste water.

    At 50 flushes a day (which seems a trifle excessive), you’d payback the cost of the butt in just under two years, and be up £150-ish per year after that.

    Then there’s the extra plumbing, separate header tank and a pump from the butt. Call it another £600, for a grand all in.

    Pushes the payback out another four years, to six.

    It gets really exciting as it appears that rainwater from your roof, prior to about 1970, probably went into the foul, but after, into a separate surface water sewer. Which is where some roads discharge into. That surface water sewer will discharge into rivers or the sea directly, and motorways and some A roads have some sort of pre-processing for pollution for that run-off.

    At which point, I start to suspect that is where the 400,000 number comes from.

    Then you can get into grey water recycling, which gets expensive, to the point where any cost savings ultimately accrue to the next buyer of the house, as the payback period is so long.

  24. I did some sums on this a few years back. Roughly the same amount of water falls on a typical house in London as is used in a year for non-food stuff (houses are the worst case scenario, so no problem that most people live in flats). The Tideway sewer storage tunnel costs about £3.8bn. If a reasonable proportion of buildings in London were collecting rainwater and spreading the output over time this tunnel would be unnecessary. So at £3k a pop, you could put collection systems on 1.3 million buildings for the same amount. So even if my numbers are way off, it *is* worthwhile in high density areas.

    A non-combined sewer system is an alternative and even more efficient in new developments, though that is much more prone to blockages and would (for the same reasons as Tidewater) be impractical and more expensive to retrofit in urban areas.

  25. The Chiltern village where I live only got mains water in the 30s. Prior to that, people collected rainwater and many houses had a ‘well’, a large underground cistern to hold the water, into which you dipped a bucket. The unlucky ones got to use the village ponds – those reserved for human consumption had a white fence to prevent animals drinking from them – I presume the water was boiled before drinking. Back to the future, comrades!

    Many of these cisterns are still there, as one chap down the road discovered a few years ago:
    I believe updated versions of this arrangement are common for remote dwellings in Australia, which have no mains water, particularly Queensland with ‘wet’ and ‘dry’ seasons.

  26. Well Chris, I have seen the old water tanks on some Qld dwellings. Though they’re not common in Brissy these days.

    As for waste water, I noticed during the Great Drought that, while all sorts of rubbish was pushed to encourage the plebs to save water, no one suggested just diverting the gray water to water your lawn. I always assumed this was because we needed to donate the water we’d just paid for to make sure the sewers didn’t clog up.

  27. So, wait – the core problem here is that in Britain your sewers just run straight into the rivers?


    I’m finding that hard to believe. Maybe in a few areas here and there that have managed to not get rebuilt in the last 120 years. I can’t imagine this being a serious problem.

    The US has places older than that and our shit isn’t being flushed into the rivers.

  28. @ Agammamon
    No, the outlet for cleaned-up water, after treatment to remove the sewage, runs into rivers or seas. [If it didn’t the clean water from the sewage treatment plant would create a river].
    The complaint is that one water company has allowed overflows of dirty water from the inlet pipe to the outlet when too much flows in (with a few overflows of overwhelmingly rainwater mixed with tiny amounts of sewage in flood conditions in each of several other other areas – but the media add all the incidents around the country to make a bigger headline)

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