# Forum Home Renovation Water Saving Garden Ideas  Tank water off lead flashed roof

## Compleat Amateu

G'day all 
Thinking of installing a water tank, primarily to top up the swimming pool. (if plants need watering, they die and get replaced by ones that don't). 
However, I have carefully re-flashed the roof using lead to replace the sh*t flashings that were there. So can you finish lead flashings in such a way a to make them OK for pools? Not to drink, just to swim in? Paint? Ormonoid? 
Thanks

----------


## barney118

?? Avoid lead at the best of times. Use Aluminium? Colorbond? what sort of roof is it? If its steel then you will have corrosions probs sooner than you know.

----------


## Compleat Amateu

Nahhh, tile roof, lead is definitely the way to go given the roof structure.  The first flashings installed were Alcor, just crap, so in the process of replacing them, only about 150 to go! 
So the question becomes, can you finish lead somehow?  Paint? Ommoniod and paint?  ANOther solution for sealin the surface?

----------


## bricks

I understand the issue you have here however, Is the amount of lead washed off the roof going to cause a health problem?
The next point of call would be is the paint / coating that you use to seal the lead going to cause the same / different problem?
Given the cost of sourcing/ installing such a barrier (in which case you still have the issues arising from bird droppings and car exhaust ) would it be a better idea to install a filter. Keeping in mind the cost / maitenance?

----------


## Compleat Amateu

Thanks Bricks, all good questions! I was thinking maybe acrylic paint (Solargard or somesuch) over the lead.  It'll stick OK, and flex OK, the question is will it prevent leaching of harmful quantities of lead from the flashing. 
I started the thread because I am a bit surprised that I can't find any useful information on the topic.  My normal source is the UK Lead Development Assoc ... but of course Poms don't have tanks and pools.  It rains all the bloody time, negating the need for both. 
In this age of water conservation, and pool-owning-capitalist-bastards like me being users of water, I'm just surprised that there don't seem to be any views, or even debate about views! 
Compleat

----------


## bricks

The issues you face are difficult to quantify,
The amount of lead leaching will obviously increase or decrease with the amount of rain you have, and also with the amount of oxidisation on the surface of the lead. I don't belive that you will be able to get a definate answer because of these two variables.  
Another idea to go as an addition to a filter would be a first flush divertor, to minimise the amount of built up pollutants. For any system you would need to ensure the pool water was cycled out at a regular interval, otherwise pollutant entry and concentration will be compounding with each addition of more pollutants. 
When I get back to work next year I will look into this more, 
Interesting question......

----------


## Compleat Amateu

G'day Bricks 
Good idea on the diverter. 
But, won't ANY addition of lead into the water - even if lower ppm. using a diverter - be cumulative?  That is, the pool gets filled off the roof - with a bit of lead in it - and evaporates - which doesn't remove any lead - and the pool gets topped up again with more tank water with lead in it.  So the lead concentration in the pool increases over time. 
I'd be pretty sure that:
1.  Lead concentration in the pool doesn't change with sunlight, i.e. it isn't leached out of the water;
2.  There are no helpful chemical reactions between chlorine and lead to precipitate the lead out (the 2 elements are way apart on the periodic table, but my inorganic chemistry ends there, happy to have someone say different). 
Happy to debate this one further, I can't be alone on this! 
Compleat

----------


## Uncle Bob

I would think that painting the lead should fix the problem. After all the lead won't be able to oxidise since it's painted. Anyhow that's my opinion but as I'm no expert, it doesn't mean much.

----------


## RedRaven

I've got some experince with this bugbear. 
Let me start by saying there is no such thing as safe lead.  Removing it, and all sources of it, is the only safe thing to do.  Its a horribly toxic metal, and if it weren't for lead being soft and workable, and handy for getting cars started, and fish bait sunk, noone would use it at all. 
But to add to the chemistry - 
Lead by its very nature is extremely lazy when it comes to being dissolved in water. 
Lead loves to be fixed, that is, not dissolved in water - if you think about a car battery - its takes some serious acid to dissolve lead into water. Rainwater just doesn't cut it. 
In theory, a tiny amount of lead will dissolve in rainwater and wash off the flashing with each rain.  And yes, it will slowly build up in the pool.  It will be tiny, tiny amounts however as lead builds up a protective oxide coating once its been in the weather for a while. The oxidised lead is 'safer' as its less chemically reactive. 
Lead particles (grains of oxidised lead and the like) will simply be vacuumed up when you clean the pool. They're heavy, and unless they're really, really small, they'll sink. 
The microscopic lead that does get washed into the pool could build up - unless you constantly empty the pool, the lead has nowhere to go once its in the water.  However, it does - if the pool is concrete.  Lead atoms will literally rip carbonate off the concrete, forming lead carbonate, which is insoluble in water.  You'll then vacuum that out, or it'll be incorporated into the concrete. 
Compleat is correct about lead not really reacting with the chlorine - it probably won't to any great extent, as long as there's concrete about. 
Now I've written this, why do I suspect its a fibreglass pool?  :Doh: 
In summary, I'd not be worried unless its metres and metres of lead flashing, you get acid rain, and you also drink the pool water while swimming. 
You can always have the tank water tested for lead too. :2thumbsup:

----------


## Bloss

:What he said:  risk is trivial to non-existent in the situation you describe. Lead flashing can be painted easily with any acrylic paint and that stops breakdown as well as makes the flashing look more like the roof. 
If you are using tankwater for drinking then the best courses is to ensure any lead is painted and that you do what should be done in any case (and rarely is!) - an annual maintenance activity that includes cleaning out of all sediments in the bottom of the tank. Lead and other heavy metals accumulate in the bottom of the tanks and are then stirred up and mixed into the water as new rain come in and the tank is emptied. This is a simple task and will make the water quality higher (and taste better too!).  :2thumbsup:

----------


## Bloss

:What he said:  risk is trivial to non-existent in the situation you describe - topping up the pool and watering the garden. Lead flashing can be painted easily with any acrylic paint and that stops breakdown as well as makes the flashing look more like the roof. 
If you are using tankwater for drinking then the best courses is to ensure any lead is painted and that you do what should be done in any case (and rarely is!) - an annual maintenance activity that includes cleaning out of all sediments in the bottom of the tank. Lead and other heavy metals accumulate in the bottom of the tanks and are then stirred up and mixed into the water as new rain come in and the tank is emptied. This is a simple task and will make the water quality higher (and taste better too!).  :2thumbsup:

----------

