Request for advice re: safety of drinking rainwater from roofs

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A recent forum contributor raised the question regarding safety of drinking rain water collected from roofs with asphalt shingles, observing grass die off next to downspouts. I'm wondering if the die off was just due to erosion from the heavy rains. I've never noticed a problem with die off. I've read that roof/rainwater is safe to drink, after it's filtered and purified. You can filter out particles by tying a nylong stocking to the ends of the downspouts, or using a screen over your rainbarrels. I've purchased several 75 gallon rain barrels and a good filter, so am hoping this will be adequate, since rain water may be the only source of drinking water, come next year. Could anyone give any informed opinons? Much obliged.

-- Jo Ann (MaJo@Michiana.com), March 23, 1999

Answers

It's been covered before. There will be a small amount of leached chemicals from the asphalt in the runoff water, and these chemicals include carcinogens. Therefore drinking it isn't recommended under normal circumstances. On the other hand, in a survival situation it's probably far safer than any alternative (and also probably less carcinogenic than real coffee!), and there are plenty of old folks who weren't harmed by decades of not knowing this.

If it really bothers you, an activated charcoal filter will renove these nasties with very greate efficiency.

-- Nigel Arnot (nra@maxwell.ph.kcl.ac.uk), March 23, 1999.


Roofers use big plastic tarps to keep the rain out overnight when all the shingles aren't there yet. I'm thinking that might be helpful for safe rain collection. Just makes it look like ya got a bad roof. You still have the problem of little buggies in bird/squirrel droppings, but a decent filter will take care of that.

-- Shimrod (shimrod@lycosmail.com), March 23, 1999.

Well,

When I lived in the desert, the exact opposite was true. There was grass ONLY where the downspout was located.

As for your question, you might consider an MSR filter (used by campers) with a ceramic element to filter your water. Or a Katydin or other reputable brand filter.

Also, the amount of carcinogens are probably lower than New Orleans (sic) city water. :-)

As for us, we will use coffee filters ($3 for 500) for most of the water applications, and MSR and Reverse Osmosis for cooking & drinking.

Jolly drinks a lot.

-- Jollyprez (jolly@prez.com), March 23, 1999.


MaJo,

It was my post which described the dead grass from asphalt roof runoff. In trying to repair these dead grass areas for customers, we reseeded the areas. The new seedlings never came up well, and they just died off. We even added 3" of topsoil at some places. The grass never really took. The solution is to excavate the contaminated soil, replacing it with good soil. However, we never did this because we knew the problem would start all over again.

Although the cause of this effect seems to be the type of roofing, I can only assume that it is. The Northern grasses here on L.I., NY are more delicate than Southern grasses. I have not noticed this problem with other plants. It does not occur at every downspout. So, it could vary with the age of the roof, or, the brand and quality of the tiles.

I do not want to discourage you with your project. I am sure this problem, if your roof has it, can be circumvented. I put this information out there as a warning. Hopefully someone, who knows more than I, can pinpoint whether or not asphalt roof shingles exude a harmful substance. If that question is answered in the affirmative, then it must be determined if a type of filter is effective in seperating that substance from the water.

Do not give up on your roof as a source of water.

-- Jim (jamesfw@earthlink.net), March 23, 1999.


A minor point. When it first starts to rain, atmospheric pollution is often captured by the falling rain drops. Ever notice that funky smell when it starts raining? <:)=

-- Sysman (y2kboard@yahoo.com), March 23, 1999.


I saw a condensation tent demonstated once, but haven't done it yet. A piece of tarp, (plastic, nylon,etc.) is spread over a pre dug hole Approx 6' diameter by 4' deep in the center, and allowed to sag in the center. Temperature differences between the air and ground will cause condensation to form and roll down to the center, where a small hole is cut to let water drip into a container.

-- KoFE (your@town.USA), March 23, 1999.

This discussion has all centered on rainwater off asphalt roof shingles. What about cedar shakes? Any problems there? Hoping we can use rain run off for our birds (emu).

-- Valkyrie (anon@please.net), March 23, 1999.

The grass situation may hinge on whether you have any metal fittings which leach metals into that particular downspout. In the south, roofs tend to mildew. If you look below metal through-the-roof vents, there is often a streak with no mildew. I have been told that this is because the leached metals inhibited growth much like copper impregnated anti-fouling paint inhibits marine growth on boat hulls.

-- Puddintame (dit@dot.com), March 23, 1999.

The grass die-off at the bottom of the downspout may also be something very simple. That particlar area is the first to get water and the last to dry. Could be that all that moisture is simply drowning the grass at that point. Problem would be compounded if the soil were clay or other slow-draining material. Just a thought from a long-time gardner....

Dan

-- Dan (DanTCC@Yahoo.com), March 24, 1999.


There are hundreds of thousands, maybe even millions, of country people across Australia who drink their roof rainwater. I have been doing so since my move to southern Queensland seven months ago. It is fine, and tastes better than chlorinated city water. (Last year in Sydney, we had public health scares with Guardia and Crypto Sporidium parasites in the treated city water supply! I have a galvanised iron roof. Some purists advise adding devices that divert the first few minutes of new rainfall to a separate container, so it can be dumped in the garden and not drunk. Other good advice is to keep the gutters clear of old twigs and leaves, bird poop etc. I must confess I have been lax. I haven't done either, yet.

-- David Harvey (vk2dmh@hotmail.com), March 24, 1999.


In my opinion, those scares didn't mean anything. During the second lot of scares, I basically kept drinking the water regardless and nothing happened to me. I think that everyone had been drinking the water for years, having their share of giardia and cryptospordium (sp?) without noticing.

In any case, I'm seriously thinking of a way to catch rainwater myself.

-- Leo (lchampion@ozemail.com.au), March 24, 1999.


Filter through activated carbon will remove gross organic oils and the like. There's alot of dust present on most surfaces just prior to a rain, so you will want to let that get washed off before you start collecting any of it.

Cedar Shakes (do they have preservative on them, better find out about that!).

A tarp set up to collect rain water is probable the best bet. They did that in Sareavjo.

-- filter (Ditto@That.ACF), March 24, 1999.


Dan,

The die off at the bottom of downspouts is not caused by erosion. When we plant bluegrass or perennial ryegrass seed in these areas, the seedlings die soon after germination. The soil is somehow contaminated by the roof/gutter/downspout system. My guess is that the petrolium product within the felt tiles causes the contamination.

Again, it does not occur on every property. So, it is still a mystery to me. If I were to consider my roof as a source of water, I would conduct a little experiment by trying to grow grass by the downspout outflow area. Observation of how the grass does will indicate if my roof has this pro

-- Jim (jamesfw@earthlink.net), March 24, 1999.


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