Rainwater storage

mickdw

With the budget telling us that water charges on defo on the way, I think alot more people will be considering using rainwater in there homes. I know there are various systems for this. I just feel that they are very expensive and usually involve a huge underground tank. I think, alot of benefit could be had from something much cheaper & smaller considering the rainfall we get.
Anyone installed something useful on a budget? Even something with limited storage could reduce bills significantly

bongo2

I connected a water butt to a downpipe and use the water it collects to water plants in the garden. Bought it in the local coop for about 50 euro. I think it holds about 200 litres

If you're doing this on a budget (pun intended ), consider one of those 1000 litre bulk liquid containers they cost about €80 or so from the local Agri-suppliers or free if you know the right people at the local industrial estate.

Bury it in the ground with a weak cerment mix to stop it caving in then fit a submersable pump into it to draw into a tank in the loft (for toilet flushing only without treatment) then run the rainwater into it.

That is my plan, I have delayed because there were other things to do first but water rates moves this job up the list a few notches.

baza1976

any links to this kind of thing??

I was thinking of using the rain water for flushing toilets and such. What about using for washing machine??

clint_eastman

i got various literature from companies doing these systems at the show in millstreet....ballpark figures were in the region of 3-4k, supply only.

i'd definately like to try and do this myself....its not rocket science.

tank for collection, submersible pump, inline uv filter (if wanted), tank in attic and associated plumbing and electrics....

any opinions?

mickdw

I think a filter would be advisable even for use with toilets to prevent blockages at the ballcock etc. I dont see a problem using this filtered water in washing machine.

basic system:

cheap tank buried on site collecting surface water from gutters etc. Overflow pipe to soakpit or drain etc.
stored water pumped to attic storage tank as required via float switch in attic tank. Attic storge tank supplying toilets, outside taps etc.
You would then need a mains supply to prevent the system running dry when no rainfall.
One way of doing this would be to add a mains supply to the underground tank via a ballcock at a level of about 9" from base of tank. With this is place, the ballcock will stop mains supply if rainwater is above 9" high in tank.
The only down side of this is that you end up having to pump the mains water up to the attic tank if rainwater is in low supply and this is not an efficient as it could be.
I must have a think about it.

baza1976

with respect to the under ground tank running empty. Would it be possible to have a valve somewhere next to a sight glass, lets say in the utillity or kitchen, when sight gals is low turn valve and then turn off when at certain level on sight glass. Just an Idea, not sure how you would hook this up though.

To tell the truth in the last 2 years I don't think the tank would have been emptied :eek:

mickdw

There is alot of ways to do these things.
The system I suggested above is fully auto and does everything the factory units do.
For your idea, you could just put an electric float switch attached to ballcock in the underground tank. This could be linked to anything really. You could have a warning light turning on or better, attached to a motorised valve which would switch on the mains water.
Actually, that is a good solution as instead of allowing the mains into the under ground tank and then pumping it, the motorised valve could allow the mains water straight into the attic tank for toilets etc. All you would need up at that tank would be a ballcock.

So if loads of rainwater in underground tank, motorised valve will have mains shut off and rainwater will be pumped to attic if attic tank goes low.
If no rainwater, motorised valve lets mains flow to attic to fill the same tank that the rainwater fills. Level of mains water in that tank is controlled by ballcock.
Thats not a bad system.

Components,
Underground tank
Some form of pump fitted to underground tank & simple filter
Attic tank with float switch to control rainwater pumping & ballcock to control the mains water.
Motorised valve & float switch to activate mians flow when required.
That wouldnt cost a whole lot & would be certainly worth while. On a new build, the cost would be tiny.

Wonky Knees

I think this is going to be a developing area especially for new builds. I'd like to think that a grant would be offered at some point. Such a system will help keep the bills down but also ease pressure on our streams and rivers.

The advantage of grey water storage is it low set up cost compared to domestic turbines - another good idea if they can design better domestic turbines at a more affordable price. Who knows one could even envisage a system where (like feed forward turbines) you sell back excess (filtered) water to the water works.

mickdw

mickdw wrote: »

I think a filter would be advisable even for use with toilets to prevent blockages at the ballcock etc. I dont see a problem using this filtered water in washing machine.

basic system:

cheap tank buried on site collecting surface water from gutters etc. Overflow pipe to soakpit or drain etc.
stored water pumped to attic storage tank as required via float switch in attic tank. Attic storge tank supplying toilets, outside taps etc.
You would then need a mains supply to prevent the system running dry when no rainfall.
One way of doing this would be to add a mains supply to the underground tank via a ballcock at a level of about 9" from base of tank. With this is place, the ballcock will stop mains supply if rainwater is above 9" high in tank.
The only down side of this is that you end up having to pump the mains water up to the attic tank if rainwater is in low supply and this is not an efficient as it could be.
I must have a think about it.

That is how I intend to do it except for the mains water standby will go directly into the loft tank, the same way as a standard attic system except that the ballcock float will be set lower.

heyjude

Not wishing to rain on anyone's parade, pardon the pun, but surely the viability of something like this depends heavily on the size of the free allocation that every home is supposedly going to be given, the extent to which you are likely to exceed this and the level of charges that apply once your 'free water' is used.

Leaving aside the upfront cost of installing exterior and interior water storage tanks, installing all the piping and pumps required etc. what would the day to day running costs of the pump be, compared to the likely level of water charges ? In other words, would the water charge savings exceed the weekly running costs of such a system ?

I already use a water butt to supply much of the water for the garden and am constantly amazed how much water you can collect off even a small roof.

baza1976

Deleted User wrote: »

That is how I intend to do it except for the mains water standby will go directly into the loft tank, the same way as a standard attic system except that the ballcock float will be set lower.

This is what i was thinking too. To control the mains and rain water inot attic tank use 2 ballcocks. The mains ballcock at a lower position than the rain water.
I prefer something mechanicla rather than electrical. esp with motorised valve. I must go through 2 of them everyyear in my house(they are in out heating system). I wouldn't like one to "stick open" in the attic, even with an over flow

heyjude

heyjude wrote: »

Not wishing to rain on anyone's parade, pardon the pun, but surely the viability of something like this depends heavily on the size of the free allocation that every home is supposedly going to be given, the extent to which you are likely to exceed this and the level of charges that apply once your 'free water' is used.

Leaving aside the upfront cost of installing exterior and interior water storage tanks, installing all the piping and pumps required etc. what would the day to day running costs of the pump be, compared to the likely level of water charges ? In other words, would the water charge savings exceed the weekly running costs of such a system ?

I already use a water butt to supply much of the water for the garden and am constantly amazed how much water you can collect off even a small roof.

The problem is, of course, is the simple fact that this is going to be a "boiling frog" type charge, initially a generous allowance.

Then gradually over the next few years the "free" allowance will shrink, and shrink until only those that use water, only for drinking and cooking will still be below the threshold!

clint_eastman

heyjude wrote: »

Not wishing to rain on anyone's parade, pardon the pun, but surely the viability of something like this depends heavily on the size of the free allocation that every home is supposedly going to be given, the extent to which you are likely to exceed this and the level of charges that apply once your 'free water' is used.

Leaving aside the upfront cost of installing exterior and interior water storage tanks, installing all the piping and pumps required etc. what would the day to day running costs of the pump be, compared to the likely level of water charges ? In other words, would the water charge savings exceed the weekly running costs of such a system ?

I already use a water butt to supply much of the water for the garden and am constantly amazed how much water you can collect off even a small roof.

I agree to a certain extent on the costs and understand the dilemma i.e. worth doing or not. I do actually "think/hope" it's worth doing it because I've decided to do it... this might sound a little wishy-washy but I really like the idea of using rainwater, it kind of gives me a bit of a feel good factor.

I'd love to hear if anyone can come up with some pay back period which i know is difficult considering we don't know what the charges will be. I think that in reality when water charges come in they will not be a small token rate that'll amount to €50 pa but more around a couple of hundred which will increase in time as water (clean supply) becomes more scarce.

If I can install my own system for < €2K similar to the systems on sale for €4k then I think it's well worth it....

Joey the lips

I think all these ideas are interesting. However my only concern is the types of tanks you are suggesting to use. I imagine building regulations will insist you will have to use a "Potable water tank" for many reasons which include safety etc. So if you going to design a system now why not just future proof it.

My thoughs on this was

a 1000 ltr potable vertical tank buried in the garden with a sump pump and a flow switch. The problem with the current sump pump flow switches is they pump only on the pressence of water

So the correct way to really do this is have a "Prim flow" as such from the mains with a ballcock. This can be pumped with a negative head pump when called for. The rain water fill would insure that the mains would only be relied upon in the summer months when water is demand most and at its lowest in the tank :rolleyes:

So really any system is going to have to be large or be investigated to see what is the possible storage in a 3 bed semi.

clint_eastman

Joey the lips wrote: »

I think all these ideas are interesting. However my only concern is the types of tanks you are suggesting to use. I imagine building regulations will insist you will have to use a "Potable water tank" for many reasons which include safety etc. So if you going to design a system now why not just future proof it.

My thoughs on this was

a 1000 ltr potable vertical tank buried in the garden with a sump pump and a flow switch. The problem with the current sump pump flow switches is they pump only on the pressence of water

So the correct way to really do this is have a "Prim flow" as such from the mains with a ballcock. This can be pumped with a negative head pump when called for. The rain water fill would insure that the mains would only be relied upon in the summer months when water is demand most and at its lowest in the tank :rolleyes:

So really any system is going to have to be large or be investigated to see what is the possible storage in a 3 bed semi.

Hi Joey,
Do you mean that the mains water to the house would be have a take-off to feed the underground tank aswell and hence the need for a "potable" tank? Or are you saying that all water will enter the house through the underground tank? Maybe I misunderstand, could you elaborate on the set-up you're thinking of....
Thanks!

Joey the lips

clint_eastman wrote: »

Hi Joey,
Do you mean that the mains water to the house would be have a take-off to feed the underground tank aswell and hence the need for a "potable" tank? Or are you saying that all water will enter the house through the underground tank? Maybe I misunderstand, could you elaborate on the set-up you're thinking of....
Thanks!

I dont really knoe what way to go but I imagine the best way would be to branch the mains. That way you have mains as normal to the kitchen sink and all other water from the tank in the garden and through the attic tank via the pump.

I am just thinking the idea as well. But Imagine the amount of water if your in a semi D and your downhill

Mike2006

I have started a new build and considered a rainwater harvesting system but then decided against it.
My reason was as follows:

Got a few quotes, all aroung €5k or so.
I reckon tops water rates will be is €200 per year, so if you pay for the unit using mortgage money, that equates to about €8.5k in real terms..

€8.5k / €200 per year = 42.5 yrs and that does not take electricity and maintenance costs into consideration.

Crude calculation but you get the point....


A good option would be to put a cheap and cheerful barrel up on blocks at the back of the garage and put an inline filter on it and a small inline pump and use this to wash the car etc.... That would cost about €300-400 tops..

Mike.

Naux

Mike2006 wrote: »

I have started a new build and considered a rainwater harvesting system but then decided against it.
My reason was as follows:

Got a few quotes, all aroung €5k or so.
I reckon tops water rates will be is €200 per year, so if you pay for the unit using mortgage money, that equates to about €8.5k in real terms..

€8.5k / €200 per year = 42.5 yrs and that does not take electricity and maintenance costs into consideration.

Crude calculation but you get the point....


A good option would be to put a cheap and cheerful barrel up on blocks at the back of the garage and put an inline filter on it and a small inline pump and use this to wash the car etc.... That would cost about €300-400 tops..

Mike.

you get my vote

Mike2006

Mike2006 wrote: »

I have started a new build and considered a rainwater harvesting system but then decided against it.
My reason was as follows:

Got a few quotes, all aroung €5k or so.
I reckon tops water rates will be is €200 per year, so if you pay for the unit using mortgage money, that equates to about €8.5k in real terms..

€8.5k / €200 per year = 42.5 yrs and that does not take electricity and maintenance costs into consideration.

Crude calculation but you get the point....


A good option would be to put a cheap and cheerful barrel up on blocks at the back of the garage and put an inline filter on it and a small inline pump and use this to wash the car etc.... That would cost about €300-400 tops..

Mike.

That's the reason I never went for a commercial system, just did the cheap parts during the build, like an extra couple of ducts and some pipework.

clint_eastman

Mike2006 wrote: »

I have started a new build and considered a rainwater harvesting system but then decided against it.
My reason was as follows:

Got a few quotes, all aroung €5k or so.
I reckon tops water rates will be is €200 per year, so if you pay for the unit using mortgage money, that equates to about €8.5k in real terms..

€8.5k / €200 per year = 42.5 yrs and that does not take electricity and maintenance costs into consideration.

Crude calculation but you get the point....


A good option would be to put a cheap and cheerful barrel up on blocks at the back of the garage and put an inline filter on it and a small inline pump and use this to wash the car etc.... That would cost about €300-400 tops..

Mike.

Thats a very fair way of looking at it Mike, and I agree that worst case scenario that could be the payback.

But in my case, I hope to install a diy system for €2k ish of my own money which would make the payback 10 years.....but in reality i think the fees may start around the €200 mark or slightly below but will eventually (5-10years time) become a very expensive yearly rate.