Harvesting Rainwater

yellatdave · 16-10-2013 11:22am #1

As I understand it, our attic tanks provide water to the toilets/showers/washing machine/bathroom taps, etc. None of this tank water is drinkable.
But water from our kitchen taps, which are fed straight from the mains, is drinkable.

If I wanted to change the bathroom tap feed to take drinkable water straight from the rising main (like the kitchen tap) instead of the attic tank, would this be a big job?

Has anyone got this done?

loyatemu · 16-10-2013 11:25am

why?

the attic tank is fed from the mains, presumably a competent plumber could take a feed off that to your bathroom tap. Might be issues with pressure though.

yellatdave · 16-10-2013 11:52am

Final goal is to take all this lovely rainwater we're getting & have a system for pumping it to the attic tank to serve everything in the house except the taps. Don't think having unfiltered stored rainwater would be hygienic enough for teeth-brushing, so I want these to be mains-fed.

Since I know very little about plumbing, wanted to know if the feed for the bathroom taps can instead be taken from the rising main in a neat (& cheap) manner. Good point on pressure by the way. Hadn't thought of that, but don't think it would bother me.

16-10-2013 12:10pm

yellatdave wrote: »

Final goal is to take all this lovely rainwater we're getting & have a system for pumping it to the attic tank to serve everything in the house except the taps.

Unfortunately untreated/filtered rain water is good for watering the garden and little else.

Algae in the rain water will cause it to turn yellow with a green slime forming surface quite rapidly.

This may interest you:

http://rainwaterharvestingsystemsireland.town.ie/

Jimjay · 16-10-2013 7:01pm

Would you want to bath and shower in rainwater?

pixbyjohn · 16-10-2013 7:15pm

Jimjay wrote: »

Would you want to bath and shower in rainwater?

Its great for the complexion

FirstIn · 16-10-2013 9:19pm

pixbyjohn wrote: »

Its great for the complexion

I agree. Remember that girl in the Timotei add. Her hair looked great and she was washing in a stream.

I'd say go for it. You'll be the better for it.

yellatdave · 17-10-2013 7:36pm

After my little bit of research today, discovered that unfiltered rainwater (minus the major debris) can be used for the garden, toilets & washing machine. If I add a 2-filter system, (5-10 micron filter & carbon filter), I should be able to use it for the showers/bath too.

The cost of the extra filters could be offset by avoiding the cost of replumbing (so I can still feed the rainwater straight to the attic tank).
I'll have the shampoo bottle at the ready!!

17-10-2013 8:21pm

Why?

I don't think this would be very good for your washing machine.
Toilets unlikely to look very clean too

Dtp1979 · 17-10-2013 8:23pm

Rain water will look clean. My biggest concern is the acidic level. Would you bath a young child in water that might be slightly acidic??

Annasopra · 17-10-2013 9:32pm

My granny used to wash her hair with rainwater all the time - never did her any harm

18-10-2013 8:46am

Reasons that water harvesting is not popular in Dublin according to Dublin County Council include:

The relatively high cost of the systems especially if retro-fitting.
Concerns that the quality of the water may pose a health risk.
Requires some technical skills to install and provide regular maintenance.

They go on to say:

For existing premises it is generally more economic to reduce water use by fitting more water efficient appliances and changing habits and behaviours before considering the use of complex rainwater harvesting systems. It is important to evaluate the potential savings before investing in a rainwater harvesting system.

Link:
http://www.dublincity.ie/WATERWASTEENVIRONMENT/DRINKINGWATER/RAINWATERHARVESTING/Pages/RainwaterharvestingFurtherInformation.aspx

yellatdave · 18-10-2013 10:14am

The following 2009 study claimed that rainwater was safe to drink.

http://www.sciencedaily.com/releases/2009/11/091104091728.htm

While it makes for interesting reading, I would still be very hesitant to drink it.

For my purposes, a 5-micron filter + carbon filter should remove any unpleasant colours/odours & particles that could trouble a toilet/washing machine (sediment bigger than 50 microns can interfere with toilet mechanisms).

As for acidity, rainwater is almost 100% pure before it reaches the ground. If the storage tank & piping are certified for potable water use, and I put in the two filters, can't see a problem using it for everywhere except kitchen.

Dtp1979 · 18-10-2013 10:24am

yellatdave wrote: »

The following 2009 study claimed that rainwater was safe to drink.

http://www.sciencedaily.com/releases/2009/11/091104091728.htm

While it makes for interesting reading, I would still be very hesitant to drink it.

For my purposes, a 5-micron filter + carbon filter should remove any unpleasant colours/odours & particles that could trouble a toilet/washing machine (sediment bigger than 50 microns can interfere with toilet mechanisms).

As for acidity, rainwater is almost 100% pure before it reaches the ground. If the storage tank & piping are certified for potable water use, and I put in the two filters, can't see a problem using it for everywhere except kitchen.

Any scientific evidence to support your last paragraph?? I'm not being smart. I was all set to install my own system until I heard about the acidity issue. If there was evidence to support your claim I'd be delighted.

yellatdave · 18-10-2013 10:39am

Dtp1979 wrote: »

Any scientific evidence to support your last paragraph?? I'm not being smart. I was all set to install my own system until I heard about the acidity issue. If there was evidence to support your claim I'd be delighted.

I'm open to correction, but I got a lot of info from the site below, and if the Australian study says its safe to drink, it stands to reason that it can't be too acidic to shower/bath in.

http://www.whollyh2o.org/rainwater-stormwater/item/122-rainwater-quality-and-filtration.html

drag0n79 · 18-10-2013 11:04am

yellatdave wrote: »

I'm open to correction, but I got a lot of info from the site below, and if the Australian study says its safe to drink, it stands to reason that it can't be too acidic to shower/bath in.

http://www.whollyh2o.org/rainwater-stormwater/item/122-rainwater-quality-and-filtration.html

While I'm all for water conservation, I'd still have problems with showering in rainwater that has come off a dirty roof and picked up bird droppings and insects and whatever else along the way. Even if it was filtered afterwards. Do you not also need an ultraviolet filter?

A lot of the 'drinkable rainwater' studies were done with rainwater collected from carefully cleaned surfaces.

If you do go ahead with it make sure your tank overflow works properly and that you have some way to divert the incoming rain back down the normal drainpipes in case of emergency (i.e. rainwater coming through the ceiling from a leaky pipe or overflow not emptying quickly enough). For the mains at least you have the mains stopcock for emergencies.

Dtp1979 · 18-10-2013 12:02pm

drag0n79 wrote: »

While I'm all for water conservation, I'd still have problems with showering in rainwater that has come off a dirty roof and picked up bird droppings and insects and whatever else along the way. Even if it was filtered afterwards. Do you not also need an ultraviolet filter?

A lot of the 'drinkable rainwater' studies were done with rainwater collected from carefully cleaned surfaces.

If you do go ahead with it make sure your tank overflow works properly and that you have some way to divert the incoming rain back down the normal drainpipes in case of emergency (i.e. rainwater coming through the ceiling from a leaky pipe or overflow not emptying quickly enough). For the mains at least you have the mains stopcock for emergencies.

Oh a UV filter is a must

drag0n79 · 18-10-2013 12:21pm

Dtp1979 wrote: »

Oh a UV filter is a must

Definitely, to disinfect the water. OP only mentioned 5-10 micron filter & carbon filter.

18-10-2013 12:28pm

An interesting project, but the question to the OP still remains:
Why are you doing this?
From a financial point of view it makes no sense.
Installation will be costly as it is a retro fit. Maintenance and running costs will not be free either.
Form an environmental perspective manufacturing the materials will have a large carbon footprint, which I would think would outweigh the environmental impact due to your reduced water demand for Wicklow County Council.
As per the link from Dublin County Council if the enviroment is your primary concern you may be better off looking at using appliances that consume less water.

dathi · 18-10-2013 5:04pm

drag0n79 wrote: »

While I'm all for water conservation, I'd still have problems with showering in rainwater that has come off a dirty roof and picked up bird droppings and insects and whatever else along the way. Even if it was filtered afterwards. Do you not also need an ultraviolet filter?A.

as apposed to using the water supplied by your council ? EPA report "the provision and quality of drinking water 2011" says 1.3% of public supplies 10% of group water schemes and 7.4% of private wells tested had ecoli present

18-10-2013 5:54pm

dathi wrote: »

as apposed to using the water supplied by your council ? EPA report "the provision and quality of drinking water 2011" says 1.3% of public supplies 10% of group water schemes and 7.4% of private wells tested had ecoli present

....but it would be far cleaner than rain water and perfect for toilets, showers, washing machines etc.

dathi · 18-10-2013 7:34pm

how would it be cleaner if you are one of the unlucky 10% that has e.coli supplied to them in their drinking water? the op said that he was going to filter the rainwater so that would remove any dirt from the water. if he puts a uv filter on it as well it would kill any bacteria leaving it cleaner than the above 10% and if you are worried about the acidity of the water(cant see why) you can buffer it by putting crushed oyster shells in the tank.

K.Flyer · 18-10-2013 7:49pm

The pipe work involved in retro fitting in a water harvesting system in a urban situation could be quite expensive and the costing for one particular house is not something you can go by unless both are exactly the same i.e. neighbours.
To be honest and if you think about it for a minute, careful usage and conservation should save you a lot more money than you would spend on a full on system complete with proper filtration and uv, not to mention the annual running cost.
Unless you are one for watering the lawn, washing the car and power washing around your house on a regular basis I really cannot see the savings vs the set up costs, unless someone has ALL the figures worked out.

yellatdave · 19-10-2013 3:53pm

2011 wrote: »

An interesting project, but the question to the OP still remains:
Why are you doing this?
From a financial point of view it makes no sense.
Installation will be costly as it is a retro fit. Maintenance and running costs will not be free either.
Form an environmental perspective manufacturing the materials will have a large carbon footprint, which I would think would outweigh the environmental impact due to your reduced water demand for Wicklow County Council.
As per the link from Dublin County Council if the enviroment is your primary concern you may be better off looking at using appliances that consume less water.

Various reasons, depending on my final use (which I'm still mulling over).

Financial: concur there is a large upfront cost (principally the cost of tanks). The payback period may take years, (depending on how much 'Irish Water' decide to fleece us annually). Then again, payback may not happen at all, but I figure set-up costs/maintenance would be negligible vis-a-vis water charges over the long-term.

Self-sufficiency: like the idea of this. When I consider last year's water cut-offs, or potential summertime hose-pipe bans, watering my veg garden or washing my car guilt-free sounds good. Flushing the toilets, wash the clothes, having a shower, etc., despite water cut-offs, even better!

Health: if I went the full-hog & added a UV light to make the rainwater drinkable, I could use it for 100% of my needs. No more fluoride, chlorine & aluminium mains-fed water for me... yipee!

19-10-2013 5:03pm

Best of luck with it.

Jimjay · 19-10-2013 7:04pm

yellatdave wrote: »

Various reasons, depending on my final use (which I'm still mulling over).

Self-sufficiency: like the idea of this. When I consider last year's water cut-offs, or potential summertime hose-pipe bans, watering my veg garden or washing my car guilt-free sounds good. Flushing the toilets, wash the clothes, having a shower, etc., despite water cut-offs, even better!

So if there is a drought or lack of rain where will you get your guilt free water from for tour veg or car in addition to baths, showers, washing up etc.
You must be planning one big storage tank. ;-)

Dtp1979 · 19-10-2013 7:10pm

Jimjay wrote: »

So if there is a drought or lack of rain where will you get your guilt free water from for tour veg or car in addition to baths, showers, washing up etc.
You must be planning one big storage tank. ;-)

Obviously there would be a mains back up. He's on about using rainwater for the majority of the time.

yellatdave · 19-10-2013 9:46pm

Jimjay wrote: »

So if there is a drought or lack of rain where will you get your guilt free water from for tour veg or car in addition to baths, showers, washing up etc.
You must be planning one big storage tank. ;-)

Dtp1979 wrote: »

Obviously there would be a mains back up. He's on about using rainwater for the majority of the time.

Exactly. Will have a control box giving priority to rainwater feed, but once that empties, mains water feed kicks back in automatically. Haven't calculated storage capacity needed yet.

Dtp1979 · 19-10-2013 10:03pm

yellatdave wrote: »

Exactly. Will have a control box giving priority to rainwater feed, but once that empties, mains water feed kicks back in automatically. Haven't calculated storage capacity needed yet.

I myself have only got space for 2 IBC tanks which is 2000 litres. Better than nothing I guess

Dtp1979 · 19-10-2013 10:25pm

drag0n79 wrote: »

The OP is planning on storing rainwater in his attic. I doubt his ceiling joists would be too happy with 2 tons sitting on them. And how do you get an IBC tank into your attic?

It's all interesting to think about but as has been said above, just completely infeasible post-build, cost and work-wise.

Well I'm a plumber and have access to cheap materials and free labour obviously. I'd imagine the OP is doing the same as myself and collecting the rainwater outside and pumping it to the attic

20-10-2013 9:45am

Dtp1979 wrote: »

Obviously there would be a mains back up. He's on about using rainwater for the majority of the time.

This will mean that you will have to pay the (knowing this country over inflated) water meter standing charge.

I'd imagine the OP is doing the same as myself and collecting the rainwater outside and pumping it to the attic

So you will need:
1) Tank(s) outside
2) Tank(s) in the attic
3) Buy, run and maintain a pump
4) Buy, run and maintain filtration system.

I myself have only got space for 2 IBC tanks which is 2000 litres.

All this so that you can store about €4 of water?

(Based on the cost to a business at present by Dublin County Council).
Link

Somehow I don't think that this will catch on

Harvesting Rainwater

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