Rainwater harvesting for house usage

the_amazing_raisin

Okay I'm definitely stretching the definition of the RE forum here, but I feel like there's probably some folks here who have had similar plans

I'm considering installing some underground rainwater harvesting tanks, maybe 7,500l or 10,000l

My plan would be to use a lot of the water for non potable uses within the house (washing machine, toilets, etc) as well as the garden

I was looking at the Graf water systems and they certainly seem fancy but I'm wondering if there's other options

I'd also like the potential for generating potable water from the system

Why? Had a few water issues over the years and it's kind of hard to live without (especially for over 24 hours)

From what I've read, the general advice is harvested rainwater is non potable, but can be made safe using a set of filters and a UV steriliser

There doesn't seem to be much detail on what filters and steriliser are required for certain cases

Also I was wondering if anyone knows anything about getting water tested to see if it's drinkable? I'd prefer a more scientific process than drinking some rainwater and waiting to see if I get dysentery 😬

Unfortunately there's a bunch of scam artists selling those magic water purification gadgets out there, so finding a proper water testing system is a bit difficult

con747

https://www.boards.ie/discussion/2058275122/rainwater-harvesting-for-house-usage

I use these https://fitzsci.ie/ for my well water testing and find them very good.

Jonathan

This might be of interest.

https://youtu.be/oqo1k5cbgBI

DC999

https://www.boards.ie/discussion/comment/119973080#Comment_119973080

I'd watch him teaching me to knit. He is so interesting and so above my pay grade :)

the_amazing_raisin

https://www.boards.ie/discussion/comment/119973080#Comment_119973080

That's certainly a bigger system than I was aiming for, but very interesting overall 😁

the_amazing_raisin

https://www.boards.ie/discussion/comment/119972785#Comment_119972785

Class! That's exactly the kind of thing I was looking for

How often do you test the well water? Does it need to be tested regularly or is it a one off thing?

con747

https://www.boards.ie/discussion/comment/119973310#Comment_119973310

They recommend it's tested yearly if you intend drinking it. I needed 2 tests done for a well system grant last year so should probably retest soon. You need to get the sample to them within 24hours of it being taken to ensure accurate results, I used An Post express post for mine which sat in a An Post sorting office for 3 days so Fitz Scientific got one of their reps to collect a new sample off my O/H at her job in Dublin.

I would imagine that was a once off but nice gesture, cost of the tests were about €150ish each if memory is correct. There are a number of labs around who do it and a lot of water treatment companies will do it for you but for an extra few quid compared to going direct.

The Continental Op

I'm not that sure you need much in the way of filtering. We used to get loads of crap with mains water and I just put in a fairly course string filter (looks like string would around a core). Used to clean sand out of the header tank every so often but a course filter sorted that and the occasional green water we used to get ;-(

My BiL runs a B&B in the UK and for ages all the guest went home with stomach complaints due it turns out from their stream fed water supply (his family had built up a tolerance) anyway upshot of that story is a simple quite small UV system sorted that problem out.

So I'd go with a course filter and a UV filter. The reason I wouldn't bother with fine filters is that they block to easily and need replacing too often. Finer filters maybe useful for water just for drinking but the UV filter alone would make the water safe to drink. You do need to do some occasional replacement of the UV lamp and obviously check its running.

I'd also incorporate some system that was easily cleanable on the water collection side. A first flush filter is what is normally recommended but if all the water goes into a smaller settlement tank first (like a water barrel) that overflows from near the top into the main tank then most solids will remain in the settlement tank.

slave1

Look up Life Uncontained on YouTube, they harvest from their roof and have overground tanks that pump into their container home via small pump house with all the filters etc. Such a good YT channel.

redmagic68

https://www.boards.ie/discussion/comment/119972785#Comment_119972785

they’re Drogheda based and very good. If your in the north east it nearly as easy to drop off your sample kit.

championc

I would have loved to do something like have a tank in the attic feeding the toilet cisterns. However, once they dropped the charging for water, it's unfortunately somewhat pointless

ELM327

https://www.boards.ie/discussion/comment/120017747#Comment_120017747

Pointless in cost saving terms, yes. However I believe there's a bit of a waste in purifying well water only to flush it into the septic tank!

championc

Or in my case, into the main drain.

If I ever do anything, I won't be doing any treating of it whatsoever

the_amazing_raisin

https://www.boards.ie/discussion/comment/120017747#Comment_120017747

Yeah it's hard to make the same argument as the UK without water charges

Personally I think water charges will be coming back at some point, they're just waiting for enough of a cool down.

It'll be framed as a climate action or something, which is fair enough if there's some way to avoid what is basically just another tax

For me, the main thing would be to use rainwater for the stuff where non potable water can be used (toilets, washing hands, laundry and garden) and to also have the capacity to generate drinking water if there was ever an advantage to doing so

championc

Paying per m3 is the only way to have proper conservation. Giving a household an exemption limit either unshackles the low person households, or penalizes the large families.

Ubbquittious

https://www.boards.ie/discussion/comment/120019147#Comment_120019147

They'll start adding on levys and fees and standing charges and left unchecked it could end up privatised and run up into the thousands per year. In theory it sounds reasonable to pay for it but I understand why it gets such push back

the_amazing_raisin

https://www.boards.ie/discussion/comment/120019498#Comment_120019498

I assume it would be regulated but we've seen how good the CRU is at regulating anything 🙄

the_amazing_raisin

https://www.boards.ie/discussion/comment/120019147#Comment_120019147

In general I agree but only if there's a way for someone to avoid the charges by self production and consumption

You can do that for water supply but one thing I found annoying was being charged for wastewater

I get the logic but there isn't really any way to avoid sending wastewater to the public sewers (at least in a city)

And it's impossible to meter AFAIK so you end up paying a fixed rate, in other words no incentive to cut down on waste water or stop flushing junk you shouldn't (fatbergs 🤢)

The Continental Op

https://www.boards.ie/discussion/comment/120019534#Comment_120019534

In the UK the "fixed rate" is just a factor of the amount of the water that the water meter says you've used.

Ubbquittious

https://www.boards.ie/discussion/comment/120019534#Comment_120019534

In theory you could have a long pipe sticking into the air with a nozzle and on a windy night you spray all the waste water out of that. Though the county council crowd who spent years carefully doctoring out their elaborate percolation area and proprietary wastewater treatment system rules would not be best pleased about them being bypassed in such a trivial manner

graememk

https://www.boards.ie/discussion/comment/120019534#Comment_120019534

Commercial pay per m3 for waste, on how much is consumed from the fresh water.

Hence the local mart collects all the rainwater for washing down. (They also use a separator etc)

the_amazing_raisin

https://www.boards.ie/discussion/comment/120019633#Comment_120019633

I'd be a bit more concerned about my neighbours if that were the case, they might seek a more direct form of remediation

I get the logic behind why public sewers should be properly managed and I really don't think going back to the days of everyone in a city getting dysentery on a regular basis and a 30% mortality rate is good

There is a lot of (justified) complaining from Irish Water and city councils about people flushing stuff down drains that they shouldn't, but without any incentive for personal responsibility then people will just continue to be a$$holes about it

One idea I heard about was to have a septic tank system that drains into the sewer so the water is pretreated and less work for the council to treat

The interesting side effect of such a system is that any unsuitable objects in the waste water will be caught in the septic tank and not end up in the public sewers

People might be a bit more careful about what they flush after they experience the River Styx flowing through their back garden 😱

the_amazing_raisin

https://www.boards.ie/discussion/comment/120019649#Comment_120019649

Interesting, so there's a double incentive then to use rainwater, save money on the inputs and outputs so to speak

graememk

https://www.boards.ie/discussion/comment/120019840#Comment_120019840

Yep slashed the water bill. Only water used is for the toilets.

slave1

https://www.boards.ie/discussion/comment/120019649#Comment_120019649

Unfortunately not, Irish Water inherited many large commercial premises with meterage of water in but not for water out and their stance is they are equal which I can tell you in a manufacturing company is certainly not the case. They are useless to deal with, refuse point blankly to deal with and do not reply to emails or meeting requests. And if you don't pay their inaccurate bills they will cut you off. A joke of an organisation.

Mr Q

https://www.boards.ie/discussion/comment/120025568#Comment_120025568

They really are useless with their commercial bills. And their "half yearly" bill could be 5 months this time and 7.5 months the next.

If you pay for more than one bill/meter at the same time they can't work out how to add the two together and clear the account. Incompetent would be very kind to call them.

graememk

https://www.boards.ie/discussion/comment/120025568#Comment_120025568

That's what I meant, the waste is measured on how much is used.

1m3 of water used = 1m3 of waste water. That's why the mart collects the rain water

monseiur

https://www.boards.ie/discussion/2058275122/rainwater-harvesting-for-house-usage

If you live in a bungalow installing a system that uses harvested water is fairly straight forward. Collect rain water off roof preferably in one large tank or smaller tanks connected in line. Fit a storage tank in attic with a float switch, fit electric mono pump at base of water tank wired through float switch in attic tank (When the water level in attic tank falls to a pre set level the pump will kick in and fill the tank automatically, float switch will knock off pump when tank is full)

Run hose from tank across attic with drop down to washing machine, toilets etc (but not kitchen/food prep area if water is untreated) A little plumbing with stop lever valves etc. at toilets, washing machine etc. will connect your harvested water but in case of drought or long term power cut etc, a simple turn of stop valve lever will ensure supply from original mains water tank.

the_amazing_raisin

https://www.boards.ie/discussion/comment/120025568#Comment_120025568

Yeah as much as I like to complain about the electricity companies, they're practically a pleasure to deal with compared to Irish water

Proper metering on both the supply and waste water should be mandated

You could even put some sort of automatic sampling system on the waste water to detect if commercial premises are dumping a load of chemicals or something they shouldn't

the_amazing_raisin

https://www.boards.ie/discussion/comment/120025774#Comment_120025774

I'd probably get one of the kits systems to do that (I'm lazy 😁) but the question is if I wanted to make the water drinkable then what need to be done

In general from what I've seen there needs to be at least 3 stages. Sedimentation, filtration and sterilisation

Most rainwater systems have some basic form of filtration so the harvested water should be relatively clear to start with

Sedimentation could be done with just a couple of small header tanks, the trick seems to be avoiding turbidity

Seems to be a bit of debate regarding the degree of filtration needed. I guess it depends a lot on the input water quality.

Sterilisation seems to be done by a UV steriliser mostly. Again there's different sizes available, so the question is how much is needed

Finally, you'd need a clean storage tank for your drinking water which is rated for storing potable water. Could do an on demand system but it seems more efficient to do something like a system with storage and recharge it when the tank is low

1874

https://www.boards.ie/discussion/2058275122/rainwater-harvesting-for-house-usage

Yes, definitely thinking of doing this myself in some form or another, although it was my intention to mainly do for recovering waste clean (previously potable water) from sinks/showers and filtering/cleaning as required but to be redirected to a tank that only feed toilets to reduce wastage of potable water used for flushing. It could be an idea to make it potable, but my plan was to reduce potable water use for purposes such as flushing toilets that doesn't require drinking quality water in my opinion.

I was under the impression there are assemblies of filters that can be gotten that fit under a kitchen sink (or a press) which are available with different types of filters in increasing ability to remove contaminants, some have fibre mesh filters (for grit/sediment), ceramic filters (not sure if these are the reverse osmosis filters component that remove microscopic contaminants or if that is another component) and finally UV filters. I do think these have an outlet that dumps some water during the process. You can add re-mineralisation components that put some minerals back in, I think the treated water is flowed through a calcium carbonate or magnesium carbonate material to pick up minerals cleaned out during filtering.

I thought I may have to supplement with rainfall, so I was planning for treatment to make the water practically potable. I'd hoped there was some off the shelf all in one setups that have a tank/pump as one unit that could be buried but I suspect if they do exist they may be expensive, but I think I could make up what's required, mainly I was thinking of the pump control not being simply on-off, but a controller that could switch on when all conditions are met or if not enough water to treat, that it could open a valve to feed the main supply into a tank, so possibly something with some kind of capacitive sensors as well as a float valve.

the_amazing_raisin

https://www.boards.ie/discussion/comment/120026032#Comment_120026032

I do remember an under sink one with a built in UV steriliser.

I think the main issue would be that you need to ensure water used for showers and baths is from a potable source, which is probably beyond the small unit

It's already difficult enough to stop the kids from drinking the bathwater without worrying about dysentery 😱

With older kids and adults you could probably get away with it, just keep your mouth shut during showers and brush your teeth at the kitchen sink

1874

That's why I'd opt for treating water for toilets only,not so much for how clean/treated/potable but just for volume. Im not sure what capacity would be required for treatment of collected runoff from roofs though. I'm not specifically in disagreement with paying for water,but I'm glad we don't,because it would go the way private water is in the UK are,purely for profit and not as an essential resource.It should be owned by the state and farmed out to private organisations to run under specific rules. I've a well,so it's more of a project out of interest,possibly to have a back up/minimise use of drinking water for toilets.

monseiur

https://www.boards.ie/discussion/comment/120026032#Comment_120026032

Assuming you're living in Ireland, one of the most rain washed islands in the north Atlantic, recycling sink, bath, shower waste water is beyond madness - your'e just looking for trouble unless you install expensive grease traps, hair & gunk filters etc. which will need regular cleaning / maintenance. Why not harvest rain water off roof, calculate the approx daily usage + 10% multiply by 185 - that should give an idea of the size of storage tank required. Remember that this tank will be topped up regularly and will be overflowing from October to April.