There are two distinct areas to think about when looking to create an environmentally friendly household water system. Perhaps the most obvious is how you heat your water for domestic use, but how you acquire, use and dispose of it also has a real environmental impact. On average, a person in England currently uses around 150 litres of water per day (not including virtual water used in the production of goods we consume), and over the last few years consumption figures have begun to rise. Research has shown that if this trend continues, England could see significant water deficits by 2050. The potential consequence would be less and less rivers meeting good ecological status, with summer river flows and groundwater levels decreasing further. The government has recently run consultation processes to aid in defining a personal water consumption target to go into their 25-year environment plan.
Sourcing Your Water
Most of us will, and will continue, to access water via the mains due to its relatively cheap cost. Since privatisation water leakage has been considerably reduced (around 40% from peak) with billions having been invested by the water companies to achieve this. This has seen an increase in the cost of water but has seen losses fall to around the European average. The Water Services Regulation Authority, Ofwat, recognises the importance of improvements and has set targets and gained commitments from water companies to reduce leakage 50% by 2050 (from 2017-2018 levels). Clearly you do not really have the option to shop around but Ofwat can and has held companies to account. Reporting leaks is worthwhile and most water companies will have a very straightforward method to do so, and support Ofwat in holding your supplier to account in meet their leakage commitments.
Rainwater harvesting is a good option for reducing your mains supply as it has benefits for the environment in terms of flood/run off control and can be relatively cheap to achieve. It is no more complex than capturing water that falls on a roof via a downpipe into a reservoir. Simple filters are included in the system to prevent blockages and remove larger impurities. The water can immediately be used for non-potable applications. There are both above and below ground options, including pumps where pressure is required. They range from simple water butts in your garden for watering to large, buried tanks capable of supplying to a greywater system. It is possible through additional filtration to use harvested rain for drinking water also, however, based on current economics we do not consider this here. Payback on a system will, however, most likely be around 10 years for all but the simplest applications.
Boreholes can be a cost and ecologically effective option (controlling your own leakage) for some depending on location and accessible space. For almost all households there would be no requirement for an extraction licence (over 20,000 litres per day) and a high-quality supply can be established at under £10,000 in most areas. With the average UK water bill at £400 per year payback will most likely be over 10 years and little evidence exists that it will increase resale value. There are cases where geology may impact this but advice is readily available from long established companies. It is important to be aware that any new borehole must be reported to the British Geological Survey and produced water should be tested regularly. Remember if you already have a mains water supply there is no requirement to remove this, simply make sure you have a water meter and turn it off at the stopcock.
Using and Re-Using Your Water
Households can take simple actions to reduce water consumption, such as:
Have fewer baths – A ten minute shower will typically use at least 50% less water than standard bath holds.
Using a dishwasher rather than washing in a bowl – For much the same reason as above, the shower of water produced by a dishwasher is less than that used to wash-up the same amount of crockery in a basin.
Using less water to flush – Don’t flush rubbish down the toilet, recycle it or bin it and use the low flush setting on your toilet if you have one when possible.
Don’t leave taps running - When washing, cleaning teeth or shaving. Either fill a bowl with what you need or keep turning on and off as needed.
Fix leaks – A dripping tap/pipe looses far more water than you think.
In addition to the above make sure you look at the comparative water use of your appliances and consider upgrading. Technology has moved quickly and much less water is now used by dishwashers and washing machines, pressure assisted flush mechanism and low-pressure faucets also reduce the amount of water used and recently, showers that recycle the water used have appeared.
As well as reducing your water use think about how you can reasonably recycle it. Such systems are known as greywater systems and are set up to capture “safe” used water and recycle it for other uses such as garden watering, car washing and toilet flushing. Garden use only systems can be achieved relatively simply and cheaply, but even a complex system for toilet flushing should payback in under 5 years.
Heating Your Water
For heating water for domestic use our recommended solution would be a heat pump due to its high efficiency. Correctly sized it can meet both your hot water and heating needs. Clearly the electricity for your heat pump should be sourced renewably, and ideally via your own electricity microgeneration, e.g. solar PV panels. If this is not possible chose a renewables-only electricity provider.
If a heat pump is impractical then look into solar thermal panels as a solution, whilst unlikely to meet all of your needs it can be supplemented via an electric immersion heater. Clearly if all electricity in the grid was from renewables and it was lower cost then simply using an efficient immersion heater would be a reasonable alternative, however, neither of these things are likely to occur anytime soon.
In all cases remember to lag your tank and piping to recommended standards to avoid any heat loss.