The following is a basic overview and I have included a video for a more detailed explanation.

You may have these questions.
Why espalier fruit trees onto a wire frame? Don’t they look more beautiful as a tree? Isn’t it more natural to let them grow as a tree?

Most fruit trees are the product of hundreds and sometimes thousands of years of selection by growers. They often only vaguely resemble the original species they were cultivated from and the result is thousands of different vareities.
Increased suitability to climatic or soil conditions
Larger and or better taste
Better keeping qualities

It can also result in weaker plants, more pest and disease prone and shorter lifespan. Do your homework and get the best trees for your needs.

Many fruit trees we purchase from the nursery are actually two trees grafted together. One half is for fruit production the other half for root production. Literally two trees grafted together. Very useful, not very natural. The vast majority of fruit you consume would been grown in this way.

Most fruit trees are also substantially pruned in order to increase their production and make them easier to harvest and manage.

So, hopefully that answers the is it natural question - No it’s not natural but I think it is ok, and has been going on for a very long time!)

So espaliered trees on a wire is an aesthetic issue. Done well it think the trees can be very beautiful, you can incorporate art, and plantings of flowers and companion plants under and around the espaliered trees.

Certainly you can increase the fruit production by using an espalier system. This is why the system deserves more attention. As block sizes get smaller, the system becomes more useful. It also makes the trees much easier to net so that you are not locked in a constant struggle with the the local wildlife.

Espaliered Fruit Trees published by GardenGuy06 27 February 2008
Click on the movie window to go to the YouTube source

When you sure you're going to be first, sometimes you're not!
How many people realised that Aussies were there first?

Why?
Because you can.
Independence from the water grid in the event of a systemic failure.
Choose your own level of water quality and additives.
Preserve the network dams and groundwater sources.
Reduce the power required for desalination.
Collecting rainwater significantly reduces the surge in the stormwater system that damages local creeks when arriving by pipes and addresses the local water balance by helping to infiltrate water closest to where it has fallen.

Source
The obvious source is rainwater from your roof and grey water from the shower/bath and washing machine. Using black water from sinks and toilets is much trickier and not discussed here.

How?
Do a household water balance.
Calculate the weekly, monthly and annual water needs. This is likely to include showers/baths, washing machine and dishwater, drinking and cooking and hand basin and sink use. A really important additional calculation is garden irrigation water, particularly if you are going to grow food.
Remember that monthly water needs are likely to vary considerably if you irrigate a large garden but water requirements may not differ significantly season by season inside the house.

Our water budget for a household of 2 adults and 4 children looks something like the list below. I have tried to be accurate and over rather than under estimate;

Daily use inside the house
6 x showers for 6 mins @ 10L/min = 360L
30 toilet flushes @ 6L flush = 180L
washing machine 2 loads/day @90L = 180L
Dishwasher 1load/day @ 50L = 50L
Drinking, cooking and hand washing = 100L
Total daily use = 870L (about 320,000L/yr)
Grey water portion = 700L (about 255000L/yr)

Garden use per year
40 fruit trees @10L/day/200 days = 80000L
100m2 vegetable garden on dripline @ 8L/m2/day/300days (2L/hr/0.3m spacing/12.25 drippers/m2) = 242550L
Garden hose 25L/min for 5min/day/200 days = 25000
Poultry 20L/day = 7200L
Total garden use per day over a year = 1325L (200 days), 800L (100 days), 20L (60 days)
About 350000L per year

So we can see in our household water use is dominated by garden irrigation needs, because we will grow a significant amount of our own food (and save countless food miles, and get fresh organic varieties that you will never see in the shop because they often don’t store or travel well).

Grey water will, on average, as calculated, supply about half of our daily irrigation needs (providing we are all at home using water as calculated - which of course will often not happen!). An interesting consequence of this system is the lack of need to save water by having shorter showers. Watch how happy that makes the teenagers!

Information you will need
The size of the roof area that you can safely collect water from. Beware of roadside pollutants, chimney soot deposits and industrial contaminants that may affect the quality of water from your roof catchment. If in doubt get the water tested at a government accredited laboratory.
The frequency, quantity and variability of rainfall in your specific area.
Your household water budget.
The number of days of water storage you desire, based on your water needs.

Equipment required.
Separate piping from the shower/bath and washing machine
Grey water filtration unit
Grey water storage tank
Grey water overflow diversion to the sewer
Gutters and down pipes
First flush divertors
Rainwater tanks and pumps (25000L+5000L small tank pumps to large tank)
Water switch to and from mains supply
Plumbed connections between the grey water, rainwater tanks and the mains.
Reticulation controller (separate stations for trees and gardens)
Drippers, dripline and connections

What you will need to achieve
A system that will efficiently filter your grey water for use in a dripline irrigation system.
A pump and connection to deliver rainwater to the house.
A water switch that delivers mains water when rainwater is not available.
A greywater storage unit that is automatically topped up by, or switched over to, rainwater (or mains) to deliver the volume of water required for the days irrgation.
A sewer overflow and diversion valve so that excess greywater is safely diverted to the sewer when not required, or if the irrigation system fails.
Sufficient flows of blackwater in the sewer system to prevent build ups and blockages.
Garden friendly, very low toxicity body and clothes washing products for shower/bath and washing machine (there are many, and an ever growing range of products, that fit this description).

Cost
The cost will depend on factors such as:
How much you can do yourself
The price you can obtain the necessary materials
The cost of the plumber (be prepared - get an upfront quote)
Government rebates you are able to access
The degree of self sufficiency you desire

Some of the major expenses are:
25000L tank $3500
5000L tank $1000 to $2500 (slimline)
Water Switch $1000
Pump $1000

If you do just about all of the work yourself, and have the plumber come and connect things and sign off on the installation, I estimate the system as outlined to cost around $10000.

Final words
Whether the decision to increase the level of self sufficiency of your water supply is environmental, ethical, health related or economical, or a mix of them, I reckon it makes sense.

I think that if we used our total roof catchment of about 200m2 including shed, pergola, carport, etc. and had storage for 30000L (25000L at the front + 5000L at the back where space is limited) of rainwater we would reduce our reliance on the mains supply by around two thirds. In Perth we usually have a long dry spell over summer and autumn, although we do get considerable rainstorms on the odd occasion during this period. To capitalise on these events we need moderate rainwater storage and a large catchment area (A 20mm rainfall event would return around 4000L or less than 3 days of storage!). If the rainfall was more regular and less variable we could have a smaller system for the same result.

If you have a catchment area of about 100m2 and a rainfall of 1000mm per year (i wish) you could theoretically collect 100m3 or 100000L, assuming no loses and unlimited storage. Based on our water balance, rainfall, catchment area and 30,000L storage we could run exclusively on rainwater for about 7 months of the year. Another 25,000L tank (and $3500) would only extend this by about 17 days. When running off the mains our grey water system would still supply about half of our garden irrigation needs. My experience is that things always find a way of not quite going to plan and hence I think a figure of about a 66% reduction in mains water use is likely in this scenario.

It all adds up. Our solar panels make most of our power needs, our chooks give us eggs and manure for fertiliser, and we can compost and reuse of all our own organic wastes on site. Compost can be used to good effect producing a significant portion of our fresh food. A large measure of self sufficiency in water is a natural extension of this system, and another relatively easy step towards genuine urban residential sustainability.

What do you think?