We supply & install water tanks

FAQs


Harvesting Rainwater

  1. What's the best size of tank?
  2. How much roof area do I need?
  3. Will my tank fill up?
  4. What if I can't put a tank next to a downpipe that will discharge enough rainwater?
  5. How much will it cost me to install a watertank?
  6. Can I use rainwater to top up my pool?
  7. How much more will it cost me to connect the tank to the house?

Using Rainwater inside your Home

  1. Can I use tank water throughout my home?
  2. How can I make my system more cost-effective?
  3. Is rainwater safe to drink?
  4. Will I notice when tank water is being used?

Pumps

  1. What do I need to water my garden from my raintank?
  2. Will I need a pump?
  3. How does the pump work?
  4. What happens when the tank is empty?



Harvesting Rainwater

What's the best size of tank?

If collecting water for use in your home, try to install a tank of at least 2500-3000 litres. You'll be able to fill that off a single downpipe that has a decent-sized roof catchment - say at least 40m2. If you are planning to use rainwater for more things, then you'll need to increase your catchment area. If you can, it's good to aim for a tank of up to 6000L, which could meet up to 50% of your total water use.

The ideal compromise between catchment area, tank size and expected usage will give you a continuous supply of rainwater from May through to around November. For your rainwater to last into the summer you need a much larger tank and the great majority of homes in the metro area don't have the space available.

If only watering pots and veggies, then a 1000-2000 litre tank is a good size.

How much roof area do I need to supply my tank?

There's not really a best answer - it all depends on your house, the amount of water you're likely to use and the size of tank you can install. For an average family look for at least 75m2for maximum efficiency. For ease of installation you want a large roof area draining through a single downpipe. One way of calculating your roof area is to go to Nearmap and find your house on the large-scale aerial photographs.

In theory 1 litre of rainwater will run off each square metre (m2) of roof area after 1mm of rain. There's an average of 10mm rain on a wet winter's day in Perth, in which case the 50m2 roof could yield 500 litres of water. In practice, plan on harvesting 85% of that from a tin roof, and less off a tiled roof.

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Will my tank fill up?

Your problem won't be with the tank filling - it'll be the amount overflowing unless you include an adequate overflow! Plan on some 500 litres of rainwater running off a 50m2 Colorbond roof on a wet day - so a 3000L tank would be full in 6 rainy days. In practice, you won't collect all of that, we seldom get several very wet days in a row, and you may be using water out of the tank, so it won't fill quite that quickly.

With 850mm of rainfall falling on Perth in an average year, around 170,000 litres of rainwater will run off the roof of a modest-sized 3-bed Perth home with around 200m2 roof area. All of that's not going to run into your tank, but it will fill up!

What if the only place I have for a tank isn't near a downpipe that will carry enough water?

That's fairly common! There are a number of options including:



Make use of my experience by asking for a site visit!

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How much will it cost me to install a watertank?

I can supply a tank custom made for your location, in a wide range of colours and with free delivery for around the same price you can normally get from Bunnings, Masters or the manufacturer.

A poly tank needs to sit on a bed of clean sand or level paving, and needs an overflow - ideally into a soakwell or slotted drain, otherwise you'll get a large pond after heavy rain. If you want to do these things yourself, it'll keep your costs down. Otherwise a straightforward installation with the tank connected to a nearby downpipe would be around $250-400. So your total cost will be around $1000-$1500 depending on tank size and shape.

I can advise on best tank location and size, how to handle the overflow and take care of all the little things that make the job look good - such as replacing paving and painting the pipes.

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How much more will it cost me to connect the tank to the house?

We first need to ensure that there's sufficient roof area draining into the tank, and that the water quality will be good enough. That may mean connecting to a couple of downpipes (for example the main roof and a patio roof) and adding rainheads to do a better job of keeping leaves etc. out of the tank that the strainer basket will by itself.

A 3000 to 5000L tank with a submersible pump and a straightforward connection back to the house plumbing will cost around $3000-4000 for the complete system. With a more complex water catchment and plumbing connections budget up to $5000-$6000 for an existing home.

If you've got a tight budget, a circular tank costs less if you have the space, and a smaller, surface-mounted pump may have sufficient capacity for your needs.

These prices are only a rough guide...to give an accurate price it's necessary to see the actual site and what's involved - ask for a site visit and free quote!

Can I use rainwater to top up my swimming pool through the summer?

Of course, but be aware that even a very large tank for the metro area may not have sufficient capacity to be able to do this throughout the summer. Evaporation rates through the Perth summer are typically 8-10mm per square metre per day. So a modestly sized uncovered pool of 15m2 will lose 150 litres of water on a January day. Even covering the pool on days when it's not used, that could add up to over 10,000L over a season. Financially, it makes more sense to use the water inside your house through the winter.

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Using Rainwater inside your Home

Can I use tank water throughout my home?

There are several ways of using tank water inside your home. Remember that the more water you can use from your tank, the better value your investment becomes. Space you've made inside your tank by using the water allows the next rainfall to refill it rather than going to waste.

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How can I make my system more cost-effective?

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Is it safe to drink water from a rainwater tank?

Many people prefer the taste and routinely fill their kettle from a water tank rather than the kitchen tap. However, the Health Department points out that although the risk from consuming rainwater is low in most areas other than where there's heavy industry or very heavy traffic, the microbial quality of water from domestic tanks is not as good as the urban water supply. Scheme water is also fluoridised, which most people regard as being beneficial to oral health in both children and adults. So it really comes down to your location and personal perspective on life as to whether you want to drink it.

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Will I notice a difference when tank water is being used?

Your rainwater tank pump is selected to supply the same water volume and pressure as you have through your mains water supply. You'll get the same or possibly greater pressure out of the tap, with no lag between turning on the tap and the water coming out.

I recommend using a submersible pump, fixed inside the tank. They're very quiet and you may not hear it running. A small stand-alone pump is cheaper but somewhat more noisy

Pumps

What do I need to water my garden from my raintank?

If you have pots or veggies that you currently water with a watering can, then a rainwater tank could be a good water-saving alternative. A 1500L tank which would fit into a small backyard or patio area would fill 150 standard watering cans. If you want to run a hose then a small pump is recommended to get sufficient pressure.

Remember that it's often during the summer when you most want to water your plants, which of course is also when there's little or no rain to refill your tank. But a short, intense rainstorm in January can often fill an empty tank that's connected to a single downpipe.

Before you install your tank it's worth thinking of what else you can might use the water for in future. Additional filtration in the form of rainheads or a first flush, or a larger tank, may be a good investment. And make sure your selected tank comes with a lid that will exclude sunlight - it will help keep your water cleaner, especially if it's stored for a while.

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Will I need a pump?

Unless your tank is raised up by several metres a garden hose will only work at around the height of the tank base. If you lift it to raise hanging baskets, or as the level in the tank falls, pressure will become insufficient to get much more than a trickle. The water pressure from your tank will be insufficient to run anything in the house. If your tank is full it may dribble out a downstairs tap or fill the toilet cistern, but the pressure will be too low to run most appliances.

How does the pump work? Do I need to turn it on and off all the time?

I supply automatic pumps. That means that if they're left switched on that they'll automatically start as soon as a tap is turned on or reticulation valve opened and pressure in the pipe drops. When the tap is closed, the pump will turn off within a few seconds after re-pressurising the pipe.

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What happens when the tank is empty?

Your pump needs a float switch to ensure it automatically turns off when there's no water left in the tank, otherwise it will be damaged by running dry Some submersible pumps incorporate the sensor inside the pump so there is no separate float switch

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