Safety of rooftop rainwater

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Rikkitic

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#159897 16-Dec-2014 16:43

I couldn't decide whether to put this in Health and Fitness or DIY so I put it here instead.

We live on an old farm with some old systems. Drinking water comes from a spring and is super-healthy, but also super-hard. It destroyed a new wetback in about six months and has done much damage to water heaters and other items.

Different water softeners were ruled out for different reasons. Instead, we now have a dual system, with collected rainwater for hot water and the spring for cold water. This spares the hot water heater and wetback, and improves laundry and hair care. We don’t drink the roof water but because it feeds the hot water system, it is used for dishwashing and bathing. My question is if this can pose a potential health risk, and how much should I worry? All the on-line advice I can find assumes all water comes from one source, which is not the case here. Like I say, we are not drinking it.

The roof is corrugated iron, very old, covered with pollen and bird leavings and probably fertiliser from aerial drops on neighbouring paddocks. Is there anything to be concerned about here, and if so, what can be done?

Plesse igmore amd axxept applogies in adbance fir anu typos

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#1198506 16-Dec-2014 16:49

You could probably look at painting the roof ( after water blasting it)

But at a minimum you should have a first flush diverter, to dump the most contaminated water in each rain event,

http://www.marley.co.nz/products/rainwater/rainwater-accessories/first-flush/

MikeSkyrme

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#1198507 16-Dec-2014 16:50

000's of New Zealand homes are supplied by rooftop rainwater collection systems.

There is always a potential for adverse health effects for consumption of water collected in this manner, but I have personally not heard of any cases.

I installed a filtration (mesh for solids, and charcoal) system and UV sterilisation rig on our tank outlet. No worries so far.

Michael Skyrme - Instrumentation & Controls

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#1198530 16-Dec-2014 17:13

Rikkitic: I couldn't decide whether to put this in Health and Fitness or DIY so I put it here instead.

We live on an old farm with some old systems. Drinking water comes from a spring and is super-healthy, but also super-hard. It destroyed a new wetback in about six months and has done much damage to water heaters and other items.

Different water softeners were ruled out for different reasons. Instead, we now have a dual system, with collected rainwater for hot water and the spring for cold water. This spares the hot water heater and wetback, and improves laundry and hair care. We don’t drink the roof water but because it feeds the hot water system, it is used for dishwashing and bathing. My question is if this can pose a potential health risk, and how much should I worry? All the on-line advice I can find assumes all water comes from one source, which is not the case here. Like I say, we are not drinking it.

The roof is corrugated iron, very old, covered with pollen and bird leavings and probably fertiliser from aerial drops on neighbouring paddocks. Is there anything to be concerned about here, and if so, what can be done?

Our water comes from the roof.

You simply ask your local water pump supplier to install UV filtration and barrier cartridge filtration. The water will then be fine.

nathan

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#1198541 16-Dec-2014 17:28

And no fluoride

cr250bromo

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#1198560 16-Dec-2014 18:22

Grew up on tankwater collected from the roof with no filtration (although the sediment dropped to the bottom of the water tank)... still here to tell to tell the story ;)
When I moved to the city I noticed how different the water tasted, although I'm used to it now.

Jaxson

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#1198591 16-Dec-2014 19:13

MikeSkyrme:

I installed a filtration (mesh for solids, and charcoal)

Charcoal is typically to remove chlorine and odours, neither of which you should have on a rain only supply. Odour from tank tends to mean something was once swimming in the tank, and is now floating in the tank...

To the OP:
Have you had your spring water tested. I'd want to check for Nitrate levels. You said you have discounted water softeners, so I'm assuming there is some iron or manganese in your spring supply?

With regards to the two systems, just some general thoughts really:
If you install UV then you'd kinda want to be passing all your water through this. If it's a closed spring then maybe no need, but just a thought.

Rain water is acidic. Do you have a concrete tank? If not then look out for blue staining in the bath etc IF you have copper piping or a copper hot water cylinder. (though not an issue anymore if you're not routing that source through the wet back).

Basically Giardia is the roof collected bit to watch out for. Many people are fed off water tanks and generally it's pretty good, right up until it isn't.
It's basically like saying I haven't ever had food poisoning, which may be true, but that's doesn't mean you wont tomorrow. Over to you how significant that potential is in your life.

http://www.health.govt.nz/your-health/conditions-and-treatments/diseases-and-illnesses/food-and-water-borne-diseases/giardia

Rikkitic

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#1198626 16-Dec-2014 20:17

Thanks all for the thoughtful responses. I’m still mulling the information. It is certainly always possible something nasty could get into the spring water feed. We have discussed this before. It doesn’t seem too likely, though. The spring has been supplying this place (and others) for decades and there has never been any hint of an issue. Lime is the problem mineral, by the way. The water goes through lots of limestone. It has never been tested, except on generations of healthy people.

The tanks are plastic, one for collecting and one for holding at a higher elevation. There is also a small settling tank and another big tank that acts as a buffer for the spring water, also plastic. It has been there for years.

The spring bubbles up out of the ground. It is covered to protect it from rubbish dropping in. The water is collected at source and fed some distance via polyurethane pipes.

Again, we don’t drink the rainwater. The most likely source of poisoning I can think of is the fact that we wash the dishes in it. The wash temperature isn’t scalding but the water does get very hot in the cylinder and wetback. It actually gets hotter than it is supposed to because we had to get dispensation to leave out tempering valves due to low pressure. Is that enough to safely kill any bugs?

Plesse igmore amd axxept applogies in adbance fir anu typos

Sidestep

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#1198679 16-Dec-2014 21:21

All our house water is collected rainwater. We have leafslides, and a first flush diverter. That's all, have never had a problem.
We usually clean a tank each year, and have 3 20,000 litre tanks, so they're on a 3 year cycle.

We have a backpacker's hostel supplied by a mix of rainwater and bore water.

Because our guests drink it we do get it tested, and have a mini treatment plant.

The bore water's very high in iron & other minerals, enough to cause problems if used straight from the ground.
We batch treat it, 30,000 litres at a time, using ozone to oxidize & precipitate out the minerals, which we clear with a back-washable sand filter system (adapted from a swimming pool filter).

We use the same ozone supply to treat the rainwater (ozone's great for killing microoganisms) as we pump it from the catch tanks to the clean supply tanks.
It takes a bit of effort (and electricity) - but better safe than sorry. From the supply tanks it's pumped through to the hostel via a UV treatment & fine filter.
A test on the catch tank water will show greeblies, the clean side of the system - none.

For your case, since you're not drinking the water I'd say you're fine. You could check what temp your water actually sits at. That would give you an idea of whether your hot tank's sterilizing or incubating your water..

Jaxson

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#1199020 17-Dec-2014 12:32

Typically you'd want to make sure your hot water exceeds 60 degrees C for at least an hour a day to prevent Legionnaires Disease.

dickytim

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#1199038 17-Dec-2014 12:42

been living on tank water from our room for years now, it tastes delicious and I have not been sick from it.

We have inline filters. The bore water however has a "dirt" taste to is in comparison.

Rikkitic

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#1199070 17-Dec-2014 13:05

Jaxson: Typically you'd want to make sure your hot water exceeds 60 degrees C for at least an hour a day to prevent Legionnaires Disease.

I haven't measured it but I'm pretty sure it goes over that. When we stoke the fire up it sometimes boils and we have to open a tap to bring the temperature back down. Not sure how that will work if summer ever arrives. This is the first year we have had it.

Plesse igmore amd axxept applogies in adbance fir anu typos

Jaxson

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#1199220 17-Dec-2014 15:09

dickytim: been living on tank water from our room for years now, it tastes delicious and I have not been sick from it.

We have inline filters. The bore water however has a "dirt" taste to is in comparison.

In water treatment terms the rain water is very good, no worries there, it's just that the water source is unprotected. Birds/critters can leave 'deposits' on your roof, which are carried into your tank and then you consume them.
So the issue is not that the water is bad, it's just that there exists the potential for contamination.
Just because you have had no issues, doesn't mean that will always be the case, so treatment prior to consumption is just like insurance really and it's a personal matter as to how much you rate this.

SepticSceptic

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#1199303 17-Dec-2014 16:22

Have a rain water tank for the last 7 years, never cleaned, untreated and have had one dose of Giardia. It was the most painful bouts of guts ache I have ever had.

Eye watering painful, toilet bowl destroying.

Thought it was a dodgy curry or something at first, but the pain got worse n worse.
Doctors visit, plus a weeks worth of horse tablets, slowly came right, and took about 6 months before the stomach had lost it's "dickey" feeling.

Now, a yearly treatment of Pour N Go - basically a peroxide oxidiser. Wait 2 hours, and all good to go.

TLD

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#1199372 17-Dec-2014 17:38

Is the spring water from the surface? I'm wondering if a deeper well might give better quality water/ I live right in the middle of Marlborough's Wairau plain (Rapaura) and we get great water from a 15 meter well. We had to have a new well put down last year, and the cost all in with consent, drilling, and new pump came to $6000.

The Marlborough District Council has some excellent Groundwater information on its website

http://www.marlborough.govt.nz/Environment/Groundwater.aspx

I believe water takes 50 years to get down to 15 meters. At any rate, the drill hit water at two meters here, but they have to go deeper to avoid contaminated water from septic tank spill off.

To answer your question more directly, I know DOC huts use water collected from the hut roof, and I know a few batch owners who do the same. They collect roof water at Rarangi near the sea here, but only for irrigating their gardens because of salt spray. I know other people who live way out there who pipe their water from over two kilometres away. Out in the Sounds they have wars over water with people T-ing into other peoples pipes without asking, and their supply being cut with an axe when discovered. Heck, it's like some of those cowboy films with their range wars. Better clean and oil your Winchester rifle to keep your water safe! ;-)

Trevor Dennis
Rapaura (near Blenheim)

mattwnz

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#1199375 17-Dec-2014 17:42

A first flush system is one of the most important things, as it stops a lot of the rubbish that builds up on the roof getting into your tanks. I would also take it of a baked on roof such as colour steel, rather than a painted roof. Also I wouldn't suggest taking it off a roof with lead flashings for obvious reasons. Also make sure you put in grills, otherwise you will get dead birds in your water tanks.

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