Roof for Photovoltaics, Solar Thermal, Rainwater Harvesting, Ventilation and Light Pipes

[SteamyTea]

8 hours ago, G and J said:

our water bills are so reasonable

Wish mine were, most expensive in the country.

Mainly the sewage charge, so RWH loo flushing still needs to be charged for. How else can the beaches be used for sewage dumps.

[sgt_woulds]

You only need about 500mm head to feed a toilet cistern (with any flow restrictors removed) so a smaller tank can fit just below the eaves without issue. A 100 litre tank would provide about 20 flushes on a low-flush toilet.  My preference would be to have this tank internally for maintenance, although I have been to customers' houses where this has been done externally as DIY and it works well, if a bit ugly.

 

I agree a large underground tank is best, but not practical for all.  Either option would be easy to design-in with a new build if stipulated, and better than introducing points of failure into roofs that are already designed to be as quick and cheap to build as possible with unskilled labour.  Impossible to fix the mass builder quality issues, but we can fiddle around the edges to get minor environmental improvements perhaps. 

 

Given the number of hosepipe bans in the last few years - and weather predictions for the next 50 years - it is madness that this is not already mandated.  

[saveasteading]

21 minutes ago, sgt_woulds said:

customers' houses where this has been done externally as DIY and it works well.

I'm surprised. More info please. How often have you seen this? 

 

If it was mainstream then it could easily be economical with a tank above the wc. A pipe in through the wall is better than through the roof.

We would stop seeing this as ugly in time.

51 minutes ago, SteamyTea said:

RWH loo flushing still needs to be charged for.

But it isn't. Not round my way anyway.

[G and J]

10 minutes ago, saveasteading said:

But it isn't. Not round my way anyway.

Yet.

 

If everyone harvested rainwater then the % charged of the input water would no longer pay for our sewage system.  Anyone fancy inventing a poo-o-meter that measures household output?  Might make your millions if you patent it.  

[saveasteading]

Hang on. How many days do we get enough rain to fill one or more 100 litre tanks?

My garden water butts are seldom full.

Hence I put 10,000litres underground. When it rains I catch the lot.

[saveasteading]

1 minute ago, G and J said:

the % charged of the input water would no longer pay for our sewage system.  

But the water saved is reducing the infrastructure load and cost. 

A difficult sum.

[G and J]

1 minute ago, saveasteading said:

But the water saved is reducing the infrastructure load and cost. 

A difficult sum.

That’s centralised long term thinking.   AKA heresy.  Think of the effect on the share dividends.  
 

Bit like preventative healthcare.  Can’t afford it in this year’s budget.  😕

[joe90]

2 minutes ago, G and J said:

If everyone harvested rainwater then the % charged of the input water would no longer pay for our sewage system.  

True, but I would like to bet that currently an even bigger percentage of sewerage gets dumped into the sea and rivers anyway 🤷‍♂️ yes if it became mandatory then a different payment system should be introduced but millions of existing houses won’t be changed for a great many years.

[sgt_woulds]

3 hours ago, saveasteading said:

I'm surprised. More info please. How often have you seen this? 

 

If it was mainstream then it could easily be economical with a tank above the wc. A pipe in through the wall is better than through the roof.

We would stop seeing this as ugly in time.

 

I used to install solar panels.  Back in the year 2000 we were one of only 3 installation companies in the country and our customers were an eclectic mix of uber greenies, (uber rich too -  the average install cost for a 3kwp system was over £20k!) so we got to visit some very 'interesting' people.  

 

I don't have any pictures from the time as I lost my old hard drive a while ago, but I have seen similar things done commercially now.  I knew at least 7 people with systems like this, and visited many times over the years - we used to have great chats about what worked and what didn't.  Everyone who started with a small system like this eventually got a larger rainwater storage butt in addition, but their Heath Robinson creations kept working well.  (One lovely lady ended up with 40-odd interlinked water butts extending from her front drive to her back garden and another had dozens of fire extinguishers welded together and hung in a ring around his eaves - he was a metal artist and it looked a lot better than it sounds!)

 

The more ordinary systems looked very much like this:  Gravity Fed Rainwater Harvesting System For Flushing Toilets and other – Freeflush Water Management Ltd.

[sgt_woulds]

3 hours ago, joe90 said:

True, but I would like to bet that currently an even bigger percentage of sewerage gets dumped into the sea and rivers anyway 🤷‍♂️ yes if it became mandatory then a different payment system should be introduced but millions of existing houses won’t be changed for a great many years.

One of the excuses given for all the floaters in our rivers is that the sewage system cannot handle excess water when it rains.  If RWS is mandated, it will be interesting to see what excuses they think of next to excuse their crappy behaviour...

[saveasteading]

6 hours ago, G and J said:

Think of the effect on the share dividends

Could be done in Scotland though..although I don't know how sewage is charged.

[saveasteading]

3 hours ago, sgt_woulds said:

it looked a lot better than it sounds!)

 

3 hours ago, sgt_woulds said:

sewage system cannot handle excess water when it rains.  

I believe that. Development is allowed without increasing the infrastructure. Rainwater may be held back but is still released at 5/litres per second per hectare, which is a lot more than zero.

[Hastings]

8 hours ago, saveasteading said:

Hang on. How many days do we get enough rain to fill one or more 100 litre tanks?

My garden water butts are seldom full.

Hence I put 10,000litres underground. When it rains I catch the lot.

Pretty sure that rainfall is not sufficient in UK to supply toilet flushing needs in most houses occupied by more than perhaps one person, even if you have sufficient storage to catch every drop. My house with adjoining garage in Argyll & Bute has a big 160sqm roof and receives twice the annual rainfall than eg. Oxford yet is considered by the local authority to be insufficient for more than 2 people.

[saveasteading]

7 minutes ago, Hastings said:

160sqm roof and receives twice the annual rainfall than eg Oxford 

Assuming you get 1000mm pa, but it is really much more

1.0 X 160m2 = 160m3 or 160,000 litres.

Toilets use about 50 litres pppd I think.

So 2 x 50 x365 = 36,500 litres demand. 

 

You've got plenty. But lots of that will overflow and be lost.

You'll have the odd 30 days with no rain so need a biggish tank (3m3?), or mains as required. 

[SteamyTea]

8 hours ago, saveasteading said:

But it isn't. Not round my way anyway

Down here, if you have a borehole, but use mains sewage, you pay.

Now I could collect rainwater and not tell SW Water I was doing that, and hope they assume the house is empty, but in all fairness to SW Water, there is unique topology and geodemographics in Cornwall that makes dealing with waste very expensive.

 

Here is a screenshot of what my charges are 

Water a couple of quid, waste over 6 quid.

 

[saveasteading]

View this email in your browser   In a landmark ruling, the Supreme Court has today found that United Utilities can be held to account for the damage caused by unauthorised sewage discharges into the Manchester Ship Canal. This judgment has massive implications, setting a precedent which breaks the shield around polluting water companies – leaving them open to a potential deluge of legal action

[Hastings]

21 hours ago, saveasteading said:

You've got plenty. But lots of that will overflow and be lost.

Annual average is 1,300mm, which (discounted 20% for losses) works out at about 480 L/day.

Not enough rainfall for a household of more than 2 people when rainwater collection is the entire water supply. Normally 200L/day/person is required for a new build water supply in Argyll & Bute.

 

[saveasteading]

21 hours ago, SteamyTea said:

Water a couple of quid, waste over 6 quid.

 

the waste quantity will be measured as your water purchase quantity.

 

32 minutes ago, Hastings said:

Normally 200L/day/person is required

That is all water.  Rainwater won't be used in the  kitchen or basins/bath/shower.

 

Are you sure about 1.3m annually. I saw the weather forecast last night and it looked like 100mm was on its way.

Use the met office figures not the tourist board.   Joking...don't tell us more or we will work out your location.

[SteamyTea]

29 minutes ago, saveasteading said:

22 hours ago, SteamyTea said:

Water a couple of quid, waste over 6 quid.

 

the waste quantity will be measured as your water purchase quantity

Yes, but not legal, and certainly immoral to not pay for waste.

[Hastings]

31 minutes ago, saveasteading said:

That is all water.  Rainwater won't be used in the  kitchen or basins/bath/shower.

 

Are you sure about 1.3m annually.

Yes, 1.3m annual, Met Office data. Low lying islands are quite a bit dryer than mainland A&Bute.

Rainwater will be used in the kitchen, basins, shower.

Just trying to point out in this discussion that any roof design for water collection can only, for the vast majority of UK housing, be a partial solution and therefore unlikely to be cost effective. Unless the law is updated to allow householders to use much less if they want.

Edited July 3 by Hastings

[saveasteading]

4 minutes ago, Hastings said:

a partial solution

I agree.  One of the harvesters I put in was turned off by  the  tenant. I am now having trouble getting someone to replace the pump, as the manufacturer seems to have dropped out of the market.....because it is a small market.

 

Why am I interested still? Because there must be a way forward. But it probably needs joined up thinking, without it being frustrated by the big house-builders.

 

Hence my 'best advice' must be to use water butts and /or a tank for the garden and, if space allows,  lose the rest honestly in the ground.

 

When your 1.3m is falling, just think how clean the ground and the air are, unlike the big smoke with pollution and shortage of water.

[saveasteading]

12 minutes ago, SteamyTea said:

Yes, but not legal, and certainly immoral to not pay for waste.

I was genuinely thinking that is what they do, and it is their chosen method. So how do they quantify the sewage? 

[SteamyTea]

10 minutes ago, saveasteading said:

So how do they quantify the sewage

Based on 95% of potable water usage.

Then some formula for that incorporates the surface and highways.

While it may be a bit hard to find out if one individual is gaming the system, other than through unexpected reduced usage, if a few people on a main sewer did it, then I suspect it would trip a warning.

Flow rates in sewers are measured as they need to manage unexpected discharged to the sea/rivers.

 

When a neighbour put a bag of cement down the drain, SW Water sorted the problem very quickly, they did the same when the manhole cover collapsed on my local waste pipe (serves 6 houses).

 

As much as I dislike paying over 8 quid a cubic metre for water, it is really very cheap considering the quality delivered, and what is involved in cleaning it up.

There are not many things that can be delivered at £2/tonne to your door, and that are good enough to drink, and who would take away 950 kg of my wee and poo for £6/tonne and dispose of it safely.

 

[saveasteading]

43 minutes ago, SteamyTea said:

hard to find out if one individual is gaming the system

It isn't though. I took 600m2 of roof water to a rainwater harvester, and 40 car parking spaces to the ground. That much water is not going into the drains.

It is no better than when the rain fell on the land, but not much worse.

It is negligibly adding to flooding or causing spillage out of sewage works.

If everyone did this, the formula would have to change but maybe not that much, and our water would be more in control.

[SteamyTea]

15 minutes ago, saveasteading said:

took 600m2 of roof water to a rainwater harvester, and 40 car parking spaces to the ground

I think we are at cross purposes.

I thought you meant using harvested water to replace mains supplied water.

 

Buffering rainwater is probably a giid thing, though there will be some places with high water tables that may get localised issues if natural gullies are removed.