Posts Tagged: water

Innovation / Sustainable lifestyles — 1 Comment
7
Jan 10

Bringin’ in the rain…

August, 2009

Freshwater is one of the world’s most precious resources. So it’s handy that so much of it falls out of the sky in New Zealand. All we need to do is collect it.

The benefits

Collecting and using rainwater is one of the easiest ways to add a touch of eco-friendly self-reliance to your home and help preserve our environment. And if you are on a metered supply, it will save you money too.

Most areas of New Zealand have a pretty good supply of fresh water, but it’s not always in the right place at the right time. Like the components of any complex long distance supply system, mains water storage dams, pipes, and treatment facilities are costly and come with inherent environmental impacts, including the potential to damage the health of our river ecosystems through excessive extraction and pollution.

The mains system is also susceptible to occasional failures which leave you, or at least your precious vegetable patch, high and dry. This is particularly true in hydro-power areas like Auckland, where in dry periods water and energy authorities have to strike a delicate balance between supplying fresh water and power.

Even small roof water systems can take a huge load off of the mains supply and inspire you to be much more conscious of the water you do use, and how you use it. And they help slow the flow of water in our urban areas, improving storm water management and reducing the risk of flooding

The paperwork

You may need a minor plumbing consent from your council, or a building consent, especially if you are planning anything larger than 25,000 litres. You will also need to fit a backflow prevention device if your tank is being topped up from the mains supply, to keep the two types of water separate.

If you plan to drink roofwater, some councils require you to treat it. Others require an annual inspection of your system. On the plus side, some local authorities offer cash rebates to encourage rainwater use.

Watch out for…

Cleanliness: keep the roof and guttering clear of overhanging branches and regularly inspect and clean them. Consider fitting one of the many guttering filters on the market. The ministry of health recommends disinfecting roof water with small amounts of chlorine, but for those of us who dislike that ‘fresh from the swimming pool’ an ultraviolet light filter system costs about $1,500, plus installment.

Contaminants on the roof: You will need to unplug the system from your roof and find an alternative for a while if you use chemical paints or moss killers up there. Don’t collect from a roof which has lead, chromium or cadmium materials or is unpainted metal. Any paint used should be labelled ‘suitable for potable water supply’.

Your intake: Rainwater is naturally ’soft’ water, meaning it does not contain the dissolved minerals, like chalk, lime, calcium and magnesium mains water in some areas picks up as it percolates through the ground and into our waterways. Getting the right amounts of these minerals is important to our health, so its worth cross-referencing the decision to switch to rainwater with our dietary considerations. This is especially important if we choose a vegetarian or vegan diet, where obtaining the right mineral levels can be more challenging.

Small people: For the same reason, as well as the risk of possible contamination, some doctors advise that even filtered rainwater may not be ideal for pregnancy or for bottle fed babies.

The sums

You only need about five litres of drinking-quality water for each person a day, for cooking, drinking and food preparation. The rest – about 160 litres per person in an average household per day – is used for toilets, showering, washing, the garden, and other uses.

There are many variables, but as a very rough guide each metre of roof space you get hooked up to your system provides around one litre of water in an average year. Even in relatively dry areas, an average home with 120-150m2 provides the potential for at least 100,000 litres of free water each year. A smaller household should get by on a 25,000 litre (5,500 gallon) tank. A larger household may need two.

Metered mains supply of water costs about $1.50 per 1,000 litres, plus a couple of hundred dollars a year for water testing and meter reading. If you are in an area which is not normally metered, you may have to pay $500-$1,000 or more to get one installed. This, plus the cost of your system, suggests a payback time of somewhere around 10 years.

Unless you have a lot of roof, a lot of rain and a plenty of tank space, or you are very frugal with water use, you will probably want to keep a mains back up, to avoid costly water truck deliveries through dry spells.

Sustainable lifestyles — No Comments
7
Jan 10

Water, water everywhere?

Conserving water was once an instinctive part of being a Kiwi. Since water shortages are becoming a regular feature of summer all over the globe and water rates seem to be attached to an ever rising balloon, perhaps it’s time to revitalise a fine tradition?

The greatest hurdle to water conservation is our delusion that water is an infinite resource. An island surrounded by water, where water falls from the sky at the most inopportune moments, should be able to keep a relatively sparse population from going thirsty. But in some regions our personal needs, combined with farming, hydroelectricity, industry, recreation, tourism and more, are sucking up more water than there is available.

Minimise water usage and wastage before splashing out on expensive recycling systems. Leaking taps waste up to 90 litres a week. Put some drinking water aside in the fridge so you don’t have to wait for the mixer to run cold. When dishwashing by hand use a bowl or a plug, and use the machine on full loads only.

How does your garden grow? Watering plants accurately and in the cool of early morning or evening is most efficient. Careful planting, landscaping and mulching can remove the need for additional watering altogether. Spas and swimming pools are a real luxury in today’s climate, so at least make best use of them by inviting the neighbours round, look into water treatments which require less backwashing and keep them covered to reduce evaporation.

You don’t have to be dirty to have a clean conscience. Share a bath as a weekend luxury and shower during the week.[ii] The average washing machine load takes 95 litres, so choose an efficient model when buying, use a water-saving cycle and make sure it’s full every time. Brushing your teeth with the tap running instead of rinsing with a tumbler wastes almost 9 litres a minute.

Go check your flow. Tests for the Australian water efficiency standards and the Consumers’ Institute suggest taps and showerheads needn’t deliver more than nine litres of water per minute to work efficiently. You can test yours by running your tap or shower into a bucket for 15 seconds and then multiplying the result by four. If the flow is too high you can fit flow restrictors for about $20 a tap, or contact your plumber to restrict the whole system. This will also reduce condensation levels in your home

Using pure drinking water to flush the toilet is a crap idea! You don’t need Niagara Falls in the smallest room to deal with the situation. Adjust the flow or reduce it with a brick or specially designed space-filler in the cistern. Home builders and renovators should consider a water-saving model of toilet. The truly committed should investigate the possibilities of composting toilets, or live by the phrase ‘when it’s yellow, let it mellow, when it’s brown, flush it down.’

Toilets, cars and plants can all re-use ‘grey water’ you have washed clothes or yourself in if you use mild, vegetable based cleaning products. If you can’t convince the kids to stagger around with buckets all day, fit a gravity or pump fed grey water diversion system. But check with your local authority first. Some promote diversion, but there are restrictions in certain areas, particularly if you plan to store your grey water, rather than let it flow straight out to irrigate the garden.

You can keep the costs down by Doing-It-Yourself, but it’s not for the faint hearted. You can have the Watersmart Gully, which allows you to manually direct grey water into the garden, installed for about $2,500, or one that diverts at the touch of a button for about $3,300. For a couple of hundred extra dollars you can get an automatic Ecoplus system installed, which cleans and stores grey water for toilet flushing as well as the garden, but you may have to work harder to get the bureaucrats to agree.

Rainwater tanks are still a familiar site in rural areas. But they can also be used in urban locations on a smaller scale for use on plants, cars and/or the toilet. The Ministry of Health recommends mains water supply is used instead of rainwater for drinking and food preparation where it is available, but presumably they enjoy that hint of chlorine taste. Install a water filter for peace of mind, keep your roof and gullies clean and remember where your water comes from when considering using any anti-fungal sprays or paints up there.