-----In 2004 we bought a falling-down house and 30 acres. This blog documents our progress-----

Monday, May 14, 2007

water tanks

We're toying with the idea of getting more water tanks installed sooner rather than later. But first, there's some decisions to make.

The first question is how much capacity we need.

We know we need about 5000 gallons dedicated just for firefighting.

Dave was then thinking we could get away with having an additional 12000 gallons for household use (bearing in mind that almost everything that goes on the garden will be recycled). But a lady I talked to in Rushworth said she got through 2000 gallons in a fortnight for her household of 3 people, which makes me fear 12000 might be cutting it fine.

I'd far rather err on the side of having more rather than less capacity, not least since if we ever have to resort to trucking in water it'd be better if we had more space on-site to store it. But at the same time, water tanks are expensive so don't want to be stupid about it.

We asked Eric what he thought:

Back when we lived in the bush, we had two, 20,000 ltr (5,000 gallon) tanks. All garden irrigation was via the dam water. Dam water also supplied the toilet and the laundry (cold only.) Our rainfall was somewhere in the region of 700-800 mm per. We never actually emptied one tank all the way. I suppose that a single 20,000 ltr tank may have worked, but I wouldn't have wanted to cut it that fine. I'm wondering if the 2000 gallons (8000 ltrs) in a fortnight included gardening. My feeling would be that 2 x 20,000 ltr tanks should be sufficient. Add a third if you want extra security.

Check how much water is required by the CFA. In most areas that I have dealt with, they required 10,000 ltrs. Generally, that can either by a "static" water supply (ie a stand alone tank that just sits there full of water waiting for a fire.) It can also be part of your domestic water tank. Do this by fitting a CFA valve at the bottom of the tank, and the outlet for house use part way up the tank. This means that there would always be a certain amount of water in the tank even if the house runs low. In any case, I would fit a CFA valve to all tanks. It doesn't cost much extra, and if the house catches on fire, most of us would like the CFA to use any water that is available.

Based on this, I'm thinking we'll plan on getting big tanks that can store 40,000 litres = equivalent to two 5000 gallon tanks to begin, but build in space so we can easily add a third. We'll also still have the little baby tanks that can be used to collect and hold water from various sheds and so forth, but I reckon you can probably never have enough water tanks when you live in a dry area. We'll also take the advice about having CFA valves on tanks at a level higher up than the house water, rather than a separate dedicated tank. That way they'll be able to use all the water we have rather than it be restricted to just one tank.

The second question is what colour/style of tank to use.

We've decided to put the tanks up the top, above the house and to go with above-ground tanks rather than under-ground as they seem to be a lot cheaper.

We started off thinking we'd mix them in a variety in different sizes and heritage colours to make it look almost sculptural, but Eric has now changed our minds:

"I use light colours like beige (I know that the work has negative connotations.) Light colours will reflect heat, keeping water cooler. Also, light colours disappear into the background a bit more. I would never use a green tank, especially dark green. They stand out like dogs ..... Metal tanks look the most "authentic." The plain galv metal tanks really suit the australian landscape. The ones used for houses have a PVC lining on the inside. It is a food grade plastic, but some people are concerned about he PVC"

He also gave us links to two suppliers:

Enviro-friendly tanks: These plastic tanks were recommended by a building biologist that I am working with for delivering water with fewer chemical contaminants than other options.

Or for metal tanks, Blue Scope Steel's aquaplate tanks.

My preference is for the latter, in the shade of 'pale eucalypt' steel.

There's a supplier in Ballarat which is probably our closest option:
BlueScope Water - Western Region, BALLARAT, VIC, 3350
ph: 0412 781 095 fax: 03 9830 4897

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