Rainwater tanks - Plastic vs Galv

[Mansfieldman]

As is the trend I am wanting to put in a Rainwater Tank. Galv is traditional put plastic more fashionable.. Any pros and cons? Which offers the better water quality?

[bsrlee]

Gal will eventually rust out, but its easy to patch if some ding-a-ling shoots a hole in it. I think it will taste the best, but that's just my old memories - if you like plastic chemicals, you can get paint-on plastic tank liner from some of the fiberglass/polyurethane manufacturers. If you don't handle it properly during installation, you can pop the bottom seam & get a B@#&%(d of a leak that is a pain to fix - make sure you have some skinny kids around to help DAMHIK.

Plastic - well it depends on the type - can be affected by UV and go brittle. When they crack or have holes shot in them, they will be more difficult to patch than Gal, if not impossible. Most of the plastic water tanks I have seen were intended for watering gardens, and plants don't complain about the taste of plastic solvents/plasticizers in their water.

You pays your money & you makes your choices.

[Gumby]

I have a plastic tank. 500 gal (2200L) and it's fine for washing the car and watering the garden. Consider how long plastic lasts under ground or in a tip - bloody ages. The water tastes OK too. :D

Cheap, easy to handle when installing, it's the way to go IMHO.;)

[DavidG]

Plastic for the smaller tanks upto 20,000L
Metal sides with bladder liner for 20,000 to 50,000L
Concrete with or without a bladder for over 50,000L

That was from one set of costings I did but it may
vary for your area.

[Wood Butcher]

The poly tanks that are made up here are UV stabilised plastic, have anti-bacterial properties and can be repaired on site if they are damaged. My old boy just had his 15yr old poly tank cleaned out last week and it is as good as the day he bought it.

His neighbour has recently bought 2x10,000 gal tanks and before he had a chance to install them, one got picked up in a wind gust and was impaled on a star picket. The manufacturers came out the next week (after he had recovered it) and repaired the damage with a gaurantee on the repairs.

Would go for poly anyday especially given the huge range of colours and shapes that they are available in.

[DJ’s Timber]

My last house had a 1000 gallon which is exposed to the sun all day long, the water tastes fine and the tank is still in good nick. I think the landlord said it was there for about 4 yrs before I moved in.

[masoth]

My opinion - it depends on what purpose you intend for the water, and where you propose mounting the tank.
"Food quality" tanks are available ......... various shapes are available (dividers to decorate the garden) ........ under the house, out of sight bladders.
Talk to a supplier of your needs/wants and be guided by the professionals.

[outback]

Easy Peasy.

Plastic.

Gal tanks rust, I am waiting to replace one I installed about 18 years ago, and it is completely kangaroo edward. It has a heap of rust holes around the top water line, as for many years we didn't use much water from that tank.

I have a plastic tank installed soon after the gal one, still going strong, I can't see why it will need replacing by me.

As others have said, you can get diffrent colours and whilst more expensive, funny shapes to get into tight places.

[Christopha]

FIBREGLASS! I have three x 4000 gallon fibreglass tanks, 2 at home which replaced the Galv tanks which barely made 20 years and the 3rd is at the beach shack. The taste is fine, no hint of any taste other than pure sweet water and they look pretty good compared to poly tanks which usually seem to have strange bulges, huge corrugations and strange 'strusions. Fibregalss is relatively simple to repair and I am told the UV isn't really a problem.

[Zed]

we have a 2000L colourbond from bluescope and its quite fine. its still new so time will tell. We use it for the garden and topping up the pool and its ok for that. I reckon if your gunna use any tank water for drinking or cooking it doesnt really matter which use use so long as you filter it for the bugs (I reckon a good charcoal filter is the go).

[TEEJAY]

If you want to purify the water recommend you get the silver impregnated ceramic filter inside the water filters you get at health stores etc. The silver in the ceramic kills the bugs the ceramic is fine enough to stop the coloids (sinking floaties, particles) and remove any chlorine in water. Charcoal is purely to remove particles - won't kill bacteria not sure if it removes chlorine either - chlorine will disipate in a container if left to air or breath.

Locally they are talking about re-cycling water into the water supply systems. We will not drink recycled sewerage water - I don't care how good they say they can make it - so be sure we will use rainwater cycled through a purier in our house for drinking.

We got on the weekend a 10 000l poly tank. As mentioned above the tanks are food safe plastic and won't have the plastic flavour.

[silentC]

You'll find it hard to get a plain gal tank these days. Steel tanks are now made from Aquaplate. It doesn't rust.

In the sizes that plastic and steel are available, the main drawback of steel is that it needs a good solid base, like a slab. Plastic tanks can sit on sand. You have to add the cost of a decent stand or pad for steel.

Don't really know of any disadvantages of plastic, never having bought one myself. I have a 5,000 gal. steel tank off the shed. My brother in law makes them, so I got it cheap, otherwise I probably would have bought plastic.

Someone told me that the water heats up more on hot days in plastic but that could be crap.

[Wood Butcher]

Someone told me that the water heats up more on hot days in plastic but that could be crap.

I know that at my old work we had a 5000gal poly tank that we used to top up our water bottles from. Even on the hottest days the water was cool.

But, the tank was a light cream colour too. If the tank was a darker colour then I agree that the water would heat up.

[MurrayD99]

We have 2 x 25k litre concrete tanks in ground and a 25k litre plastic above ground... You are not supposed to bury the plastic ones according to the manufacturer. I don't think galvanised iron tanks go very big. How big a tank are you thinking about?

[silentC]

I don't think galvanised iron tanks go very big
Biggest one my BIL makes is 5,000 gallon. I haven't seen plastic ones any bigger than that around here, but that doesn't mean they aren't available. They'd be getting a bit big to transport though.

[Christopha]

I don't think that heating up of the water is really a problem as it takes an awful lot if heat to raise the temp of a reasonable sized tankful of water... As for just using your tank water on the garden? What a bloody waste! Here in the country it's bore water for the garden and the dunny and the rainwater (filtered) is for the washing and the drinking. I have 12,000 gallons all up and in 20 plus years here we have never come close to running out, dishwasher, auto washing machine and all. Mind you, with the current drought I could be in strife this year if I'm not careful.

[silentC]

I don't think that heating up of the water is really a problem
It was a guy who makes concrete tanks that told me that, so like I said probably crap. Tell you what though, I've got a short length of polypipe that's exposed in the run from the tank to my shed and it only takes 15 minutes or so for the sun to heat that up hot enough to make a cuppa ;)

[HappyHammer]

Is the pipe used for pool solar systems poly? Whatever it is it heats up nicely my pools at about 28 degrees today...hmmmmm....

HH.

[Vernonv]

We have about 60 000 litres of water storage spread between both steel and poly tanks.

There is no difference in taste between steel and poly, however the poly delivers "clearer" water (the old steel tanks have crappy leave catchers).

We run the whole house off tank water (no mains or bore) and it goes through a twin 5 micron particle filter and then through a UV bacterial "filter".

The poly are lower maintenance and I would bet they last a lot longer than steel.

Our oldest steel tank is probably 25 years old and has been rendered on the inside and it is still leaking. We will probably be replacing it soon with a poly tank.

[silentC]

The poly are lower maintenance and I would bet they last a lot longer than steel.
What maintenance do you have to perform on the steel tanks?

Theoretically, the water that comes out of either should be the same. If you're getting lots of leaf matter in the steel tanks because of inferior leaf catchers, that's not really the fault of the tank, is it? ;)

Be interested to know what warranty you get on a poly tank? Aquaplate has a 20 year 'rust to perforation' gaurantee.

[Vernonv]

By maintenance, I was thinking more about the amount of time I need to spend keeping them going (i.e. holding clean, drinkable water) and the inconvenience it involves (leaks are always noticed just before you need to leave for work). Also, as far as I am concerned the leaf catcher is part of the tank, as is the first flush system fitted inside my poly tanks.

So for the the poly tanks it's only emptying the leaf catcher. For the steel tanks it's emptying the leaf catcher, and keeping an eye on the tank for any leaks that spring up and then filling them, and more regular "tank cleans".

The bottom line for me is that the poly tanks are easier to look after, give me better quality water (although new steel tanks would most likely have better leaf catcher/first flush systems) and I don't need worry about leaks springing up (so far anyway).

Oh yeah ... I think the poly's have a 20 or 25 year warranty.

[silentC]

as far as I am concerned the leaf catcher is part of the tank
Yes but it is not because the tank is steel that it has a poor leaf catcher. It's because you bought one that had a poor leaf catcher. There is a difference and it's important when you are discussing the pros and cons of something to restrict arguments to things that are actually attributes of the thing you are discussing.

I have a plastic strainer on mine and it seems to be OK so far, but thanks to the bushfire building regs in my area, there are no trees near the shed anyway, so no leaves to catch. The house has gutter guard all the way around, so no strainer on the concrete tank.

We don't use the first flush devices because they are not necessary if you keep the rubbish out of the gutters in the first place. You actually lose quite a bit of water with those over time too. I sometimes sit outside just on night fall and you can hear the water dripping off the roof and into the downpipes from condensation. That would all be lost if we had a first flush device. It's probably enough each night for a glass of water each in the morning ;)

[Vernonv]

I agree with you. I was pointing out my experience with my steel tanks (all of which are quite old) and I made the comment in my last post that new steel tanks would have better leaf catchers and first flush systems.

Our house had gutter guard (that black plastic coated 10mm square netting stuff). I absolutely hate it.

I found that it caused more problems than it solved. Leaves tended to get caught up in the netting and made it difficult to clean/clear. Netting ends would droop into the gutter and allow leaves in and cause blockages - and you would have to pull the netting out to clear the blockages and then refit it.

In the end I pulled it out.

I have seen a few other systems that appear to be much more robust and solve the problems I had with the netting (at a price).

First flush systems are not really there to keep leaf litter out. They are there to divert the "first flush" of water off your roof. Dust, bird poop, possum poop, etc, accumulate on the roof and when it rains these are washed off your roof and (without a first flush system) into your tank.

Some first flush systems are self draining, so that the more time between rain, the more water they divert. Others you have to manually drain. Also you can drain the first flush system onto a garden, so that the water is not totally wasted.

[silentC]

Our house had gutter guard (that black plastic coated 10mm square netting stuff). I absolutely hate it.
Ours is made from a perforated sheet of zincalume. But like I said, no trees to clog it with leaves anyway...

I know all about first flush systems. Looked into them when we built our house. I decided against them for the reasons given. They're a good enough idea in principle but I don't see the need. Since we use recycled effluent on our garden, I consider any fresh water not going into the tank to be wasted. I grew up on tank water and bit of possum or bird poop may even be good for you ;) Not sure about the wrigglers though...

[Bleedin Thumb]

and remove any chlorine in water. .


Didn't think chlorine would be much of a problem in tank water.:rolleyes:

[TEEJAY]

Didn't think chlorine would be much of a problem in tank water.:rolleyes:

Fair comment, you see i am just explaining the many benefits, even beyond those sort of such a device.

Yes I stand guilty of providing too much useful information :D

The conversation has diverged to gutter guards and first flush devises - "sickem rex!" :p

[Andy Mac]

Had one old farmer from here say poly tanks aren't much chop if you're relying on them for fire fighting!!:eek:Melting your water supply in a grass fire when you need it most, but that's probably not an issue in the 'burbs!


Cheers,

[Bleedin Thumb]

Had one old farmer from here say poly tanks aren't much chop if you're relying on them for fire fighting!!:eek:Melting your water supply in a grass fire when you need it most, but that's probably not an issue in the 'burbs!


Cheers,
I've also heard the same complaint about poly supply pipes but I'm not sure if its urban myth (or in this case country myth) as I wonder if the water in the pipe or tank would cool the poly down sufficiently ..and any subsequent eruption of water to prevent any major damage.

BTW TEEJAY I guess some people use their tanks as headers to get gravity feed thus improving poor town water pressure.:)

[bsrlee]

Good to hear they can repair poly tanks - might have to think about one for home - I'll just have to find somewhere to put my timber:cool:

As for melting in a bush fire - that is only likely to happen when the tank is empty - any poly tank or water pipe full of water is not going to reach melting point until all the water has boiled off - of course the bit of the tank above the waterline will go all saggy & be a right B$%^*(d to iron the wrinkles out :D

[Felder]

I wonder if the water in the pipe or tank would cool the poly down sufficiently
Nope.


..and any subsequent eruption of water to prevent any major damage.
And Nope.

I witnessed a poly tank let go at a fire. It successfully extinguished the fire in a 10 metre radius, but did little to the 2km fire-front. Suddenly, we had 10,000 litres less water with which to douse the flames. :eek:


When putting a deck on the back of my house two years ago, the Blue Mountains City Council insisted that we installed a 5,000 litre tank, purely for firefighting. I wanted to chuck it under the deck so no-one could see it. I did a lot of researching, it seemed that the only one that would fit under the deck (1.8m), and within the deck pillars (3m apart) was only 4,500 litres. And around $1,500.

Looked for a while like I was going to have to get a 4,500 litre and a 500 litre and connect them. :(

Last ditch effort, rang Tankworld (no affiliation, etc) in Dubbo and they had one 1.2m high and 2.86m diameter.....7,600 litres!:D $1,190!:eek: Delivered!!:eek::eek:

The point of my story is that it is a fibreglass tank, and very easy to repair (DAMHIKT :mad::mad: ). The water tastes fresh and is always cool (which may be helped by being under a covered deck :rolleyes: ). I'm a fan of my tank. :)

[Article99]

If the fire were to get that close, you'd hopefully be grabbing the folder with the insurance papers and running out the door, wouldn't you? :p

[Barry_White]

As Silent says very few gal tanks made these days for a couple of reasons. BlueScope (Previously BHP Sheet and Coil) mostly supply aquaplate which is galvanised or Zincalume steel with a food grade vinyl bonded to the interior of the tank steel.

All the tanks are usually made with a rivet system and sealed with silicone.

The other reason gal tanks aren't used much now for household water is because they used to be sealed with solder and lead based solder is banned in any type of plumbing for household use.

The reason gal tanks don't last long and end up with early perforation is from a couple of factors.

All gal tanks used to be supplied with sacrificial anodes to be suspended in the tank. They seemed to go the way of buttoned up boots or people forgot to replace them when they disintegrated.

Another factor was that with advent of copper plumbing people ran the copper right up to the tank and then you got electrolysis on the tank from the copper. BHP brought out a Technical Bulletin noting that no copper should be within 3 metres of a gal tank.

And another reason was the advent of Tile, Zincalume and Colorbond roofs in the country as the water off a Tile, Zincalume or Colorbond is pure water with no protective salts in the water and this causes the gal coating to be removed from the steel tank.

BHP tried to overcome this by trying to get the tank makers to use Zincalume and seal the tank with silicone. This was like beating your head against the wall all you got was a headache from the tankmakers.

The next move was to Aquaplate and then the government stepped in with a ban on lead solder and it all became a whole new paradigm.

As to a steel tank sitting on the ground the usually make an earth ring slightly bigger than the diameter of the tank. This is made level sitting on the ground and filled with sand. The bottom of the tank is made from double sided Aquaplate and the earth ring has aquaplate on the inside of it and this protects the steel from the wet sand.

How do I know all this. 11 years with Lysaghts trying to educate tankmakers on Zincalume and Aquaplate

Just my 2 cents worth of useless information.

[Bleedin Thumb]

Nope.


And Nope.



Thanks Brenden, always wondered about that.

[silentC]

11 years with Lysaghts trying to educate tankmakers on Zincalume and Aquaplate
We used to make Gal tanks back in the 80's. We bought steel from Lysaghts all the time and one of your colleagues probably tried to talk my old man into using Zincalume. I also remember when Aquaplate came out but it was right near the end, so never got to use it.

I soldered plenty of gal tanks in my time. The rings were riveted first with cold rivets - a two man job. The old man was taught how to do it when he was an apprentice in the early 60's and he never changed his technique.

My brother in law uses tek screws and this grey goop that comes out of a cartridge. The old man rolls his eyes every time he sees one of the BIL's tanks. "Old Tuckey would roll in his grave" - Tuckey was his boss as an apprentice.

We made a tank out of colorbond roofing offcuts in 1986. It was still holding water but leaking from pinholes when we sold the house last year.

[TEEJAY]

40 years ago when we bought our farm the house had a 2000 gal tank on the block laundry roof the frogs would live within the blocks then up and into the tank and drown.

It was mid summer and my job was to get into the tank and scoop out the 1 foot deep mush of rotting frogs. To say it was the most unpleasant sauna I have ever had would be an understatement. I do remember the smell lingered with me for weeks.

We put in a bore that went a few hundred feet down into sandstone and brought up the purest water - we then got a 20 000 gal concrete tank and life was grand for decades after that.

[Andy Mac]

I saw on the idjut box a few weeks back that some crew in Brisvegas are making corro tanks from stainless steel sheet. Something like a 40yr warranty. I don't know the joining or sealing technique used, but prolly the usual rivets, and s/s can be soldered. Would be a lovely tank if you could afford it:) .

Cheers