Rainwater harvesting

[mattc]

As i sit here with litres of it falling every second onto the roof at the moment I am considering the above.

Has anyone installed such a system themselves and what were the pitfalls. I would do the work myself so would not just pay a company £3K to do it (that can be better spent on fuel!)

cheers

 

[Dieselman]

What do you want to achieve. Garden/general use water, an underground or overground system, water for washing and loo flushing, or even drinking?

Spinal was doing this recently for general use and I have a 650 litre butt (not teh one I sit on ) for general use, including washing the car.

And guess what, the sun's just come out... :bannana:

 

[mattc]

garden/cars/loo flushing/washing too if possible? Guess thats a matter of filtration.

An above ground storage system would be easier I guess but there is space for either. I guess there are advantages for both systems depending which why I go.

Its not a question of the cost (and the savings) more the fact it seems silly not to utilise what falls from the sky

 

[Dieselman]

Most water in the house is used for flushing loos and showering, only 5% is used for cooking/drinking.
Have an outside 1000 litre IBC and a pump to pump it upto a header tank in the loft then plumb everything but drinking water into that. Sorted.

 

[Dragon]

Buy some water butts depending on how many downpipes you got and get a kit to divert to the water butts. Make sure the overflow does not flow back into the sewage system and you can claim back rebate from the water company considering how expensive now the sewage charge at the moment. I am paying twice as much as the water I use.

Rain water can only be used for washing car and watering the plant, not recommended for drinking or washing consider the amount of bird **** and dusts. Last spring was the worse with pollens and dusts from the Saharan desert. Maybe it OK for flushing the loo.

 

[mattc]

But if I want to use it for showering what sort of filtration is required? at the same time we will probably have a new condensing boiler and we have 2 showers that would be run from them. obviously that would normally use mains supplied cold which comes in at a fair old rate (and pressure). If I cannot keep up the water flow rate and pressure do the things not normally cut out? or would i be better of swapping to powerful electric showers and just feed them from a header tank above?

 

[Dieselman]

beware combi boilers never deliver sufficient hot water for more than one point successfully, and they always deliver a plug of cold water, even after just being used.

Some can accept water at lower pressure so a header tank may suffice but if you're having a header at all why go for a combi boiler, just stick to a reliable system boiler and cylinder.

For showers combi's need ones with pressure balancing as well as thermostatic, but are better than electric ones.

You can use rainwater for showering with just basic filtration. In fact rain water is better as there is no scale so you can use less soap.

Have you considered renewable energy water heating to reduce consumption of fuel.?

 

[x332race]

Does the water in the collection / storage tank need any chemical treatment to prevent build up of algae/larvae etc?

I have an empty large grp water tank in my loft left over from when I connected everthing to mains pressure so I am thinking of pumping rainwater up to this, poss using a solar powered pump and then running pipework to the 3 WC,s in my house and one for washing cars.

 

[Dieselman]

A black tank won't suffer algae, it needs light to grow.

Do you mean use a solar pump to pump water up to the header tank or to the loos from it. you won't need it for the loos as they will be gravity fed, and solar pumps are pants anyway, just use a regular pump with pressure switch and a ball c0ck into the header tank.

 

[Mondorich]

I have just moved in to my self-built home and I installled a 3000L underground water tank from Klargester, including leaf filter, in readiness for fitting the rest of the system when funds allow. You may be referring to this type of system in your original post.

When I've built the garage I will have the control unit in there to supply harvested water to bogs, washing machine and outside taps. The pipework is already in but I've bridged it to the mains supply at the moment until I get the other parts in place.

I will be using a direct system with no header tank. This relies on the pressure from a pump in the tank. Therefore it's combi all the way for me.

Naturally I had the benefit of a empty site and all the underground drainage to feed the tank was put in at the groundworks stage. Suffice to say it's been full for ages and the excess water goes to a soakaway. We draw off the odd bucket full of water for watering some pot plants but obviously haven't had to do this for some time.

I've considered using the reinwater for showering but am not going to do it for a while, if at all. AFAIK basic filtering will be sufficient, mainly to prevent damage to the boiler and/or mixer valve.

Regarding combi boilers... mine works an absolute treat and on my system, the limiting factor in filling the bath is the capacity of the bath taps, and having a second hot tap open has no effect on pressure. I can say though that the mains pressure is excellent here.

No pitfalls to report on the tank apart from the cost but I costed this in my original calculations and just bit the bullet. Careful adherence to the instructions when backfilling is essential to avoid crushing the GRP. Follow the procedure and there should be no problems.

 

[AANDYY]

Buy some water butts depending on how many downpipes you got and get a kit to divert to the water butts. Make sure the overflow does not flow back into the sewage system and you can claim back rebate from the water company considering how expensive now the sewage charge at the moment. I am paying twice as much as the water I use.

Rain water can only be used for washing car and watering the plant, not recommended for drinking or washing consider the amount of bird **** and dusts. Last spring was the worse with pollens and dusts from the Saharan desert. Maybe it OK for flushing the loo.

I will be doing this, I'm on a meter, I est. I'll save about £20/month.
I'll post details of gear and a diagram when I can figure out how to do it, more time yommorrow. :bannana:

 

[A-AvantGarde]

We've just moved into a new house that has a rainwater harvesting system installed by the builders. From what I can make out it's german (like most good things), it's made by Rewatec and it provides all our water for the flushing of the toilets and the garden hose. It can be set to feed the washing machine and has a manual by-pass to allow mains water to flow through instead.

Seems pretty good, let me know if you want me to find out anymore about the system.

 

[Dieselman]

I'd be interested to hear how you get on with it, especially for washing machine, etc. Can it be used for showering as well.?

I'm not bothered about the cost of water bacause it's cheap per-se and most of my charge is for roof drainage and water removal, due to opting to go on a meter.
I currently save about £600 p.a as a result but am interested in not using treated water for silly things so use rainwater for car washing, etc.

 

[columb]

Seems pretty good, let me know if you want me to find out anymore about the system.

Please do!

Many thanks!

Cheers
Chris

 

[Colin_b]

Living in Cumbria, the problem is getting rid of water! 3 days without rain is a drought


Be nice to reduce the water bill, though, but it doesn't seem to make sense financially for a retro-fit system.

 

[smiddyboy1]

PLease Please Please do not even consider using a Greywater system for showering!!!!!!!!!

Showers in general are considered HIGH risk for creating Legionellosis (Legionaires Disease) and thats even if its connected to the mains supply / cold water storage tank - Its due to the temperature that you shower in will be in the perfect range for Bacteria multiplication, and then the shower creating the areosol which is where you contract the disease (injestion through vapour / areosol / droplets).

Showers are disinfected every three months in many if not all (well should be) workplaces for this reason.

Without the proper filtration / dosing you should forget the idea just to save a few pounds!

 

[Dieselman]

Rainwater isn't 'greywater' and water should be heated to 50c to stop legionella multiplication. The use of copper cylinders also kills off bacteria.

 

[smiddyboy1]

Rainwater isn't 'greywater' and water should be heated to 50c to stop legionella multiplication. The use of copper cylinders also kills off bacteria.

At 50c it takes 2 hours to kill Legionella, thats why Hot water should be stored at 60C. (and capabile of achieving 50c at the tap after 1 minutes running)
Its when the Hot water mixes with the cold water it then becomes the perfect temperature for the multiplication although there may be a low risk from the hot side, but a very high risk from the cold side- so if your using Greywater / Rainwater or whichever harvesting method then there will be the probablility the water will contain the bacteria which is a natural growing bacteria.

As for the copper cylinders: They have been proven to promote stratification within the vessel and traces of the bacteria has been found within them

 

[Dieselman]

I accept your greater knowledge but understood storage to be at 55c with bacteria multiplication being killed off at 50c, with storage being the issue as oposed to the delivery point.
If it's the delivery point how does any apparatus with a mixer valve not create ideal conditions, they eject water at approx 40c.?

Does anyone know their stored water temperature.? I do and it isn't always 50+c.

 

[smiddyboy1]

I accept your greater knowledge but understood storage to be at 55c with bacteria multiplication being killed off at 50c, with storage being the issue as oposed to the delivery point.
If it's the delivery point how does any apparatus with a mixer valve not create ideal conditions, they eject water at approx 40c.?

Does anyone know their stored water temperature.? I do and it isn't always 50+c.

Its both storage & delivery point but the delivery point is where you would come into contact with the Disease, but yeah both are considered as equal risk.
Your absolutely spot on with the thermal mixing valve (TMV), but they should only be used where there is a considerable risk for causing harm (i.e. nursing home, nursery, disabled toilet etc). And have greater contol placed upon them (Sink 43c so as to be as close to the 50C without scalding), serviced every six months or within the manufacturers guidlines, and the temperatures checked and recorded monthly, even go as far as the length of pipework to the mixer valve (3 meters) and from the mixer to the tap / bath -blended water (2 meters) ......TMV's are a pain in the >>>>
A new byelay was passed in scotland where every new bath fitted should have a TMV fitted even in a dwelling house -I've still to see a publication mention it.