Harvested rainwater can be used for a number of purposes both inside and outside the home. Each litre of rainwater used reduces the dependence of the homeowner on mains water; cutting water bills and reserving clean water for cooking and drinking. In some cases, a rainwater harvesting system can reduce domestic mains water usage by up to 50%. Of course, the amount of rainwater that can be used depends on the type of system and the volume of the storage tank, as well as the usage needs of the household. Some uses will also need additional filtration and purification before the rainwater is fit for human use. Get in touch with one of our rainwater harvesting specialists to find out more.
These are the six most common uses for harvested rainwater in the United Kingdom.
Outside The House
1) Garden Watering
Some homes use hundreds of litres of drinkable water each year watering their garden, either through hosepipes or watering cans, or through automated sprinkler systems. With our weather becoming more erratic, changing radically from heatwave to monsoon in a matter of days, homeowners are becoming more dependent on garden watering systems to irrigate their lawns, crops and flower beds. Increased average rainfall in the UK means there is potentially more rainwater available at all times of year for homeowners to use, if only they could store and access it. In this regard, rainwater harvesting systems play a crucial role in reducing the pressure on the water mains at times of high demand and low supply e.g. summer droughts. And of course, plants prefer rainwater to mains water due to it being naturally soft and chlorine-free.
2) Car Washing
An average hosepipe will race through around 10 litres per minute, while a domestic bucket may hold 15 litres of water. It is no surprise, therefore, that a homeowner can easily use 10 to 100 litres of water every time they wash their car, the average being 35 litres. It is an open argument about whether hose or bucket washing is more water efficient, with some people claiming that using a hose with a trigger attachment uses less than washing with a bucket. Whether this is correct or not, either method uses mains water – purified, drinkable water that is treated for human consumption. Using rainwater to wash cars is far more preferable and environmentally friendly. Ask any window cleaner and most will prefer rainwater to give a clean finish free of streaks and spots.
3) Filling Ponds & Other Garden Features
Ponds too are far better topped up with rainwater due to its soft nature and the fact that it is free from chlorine residue that can adversely affect wildlife.
Inside The House
4) Toilet Flushing
Within the home, the most common use of rainwater is for toilet flushing. For this purpose, rainwater requires nothing more than good filtration, to remove debris and particles that might otherwise discolour the water or block valves. Older toilets can use up to 13.6 L per flush, while modern eco-flush toilets use as little as 4 L. Even so, the average person in the UK flushes 34.5 litres down the u-bend every day, a volume that can quickly mount up in family households. In these cases, the investment required to link up a rain harvesting system with the toilet cistern quickly pays for itself.
5) Clothes Washing
Harvested rainwater is also excellent when used for washing clothes, particularly in hard water areas. Rainwater being naturally soft will use less detergent and will prevent the build-up of limescale, prolonging the life of the machine. Again, for this purpose it will need nothing more than good mechanical filtration, ideally to less than 0.5mm (500 microns). Reducing the mains water used in the washing machine will represent a significant saving for most families, as this is one of the main domestic uses of water beside toilet flushing.
6) General Household Cleaning
Rainwater can be used for all types of cleaning both indoors and out. With no calcium or chlorine content it is ideal for washing floors, windows etc. and will not leave spots and streaks. We even know of one business that makes a living by collecting and filtering rainwater which is then sold to professional window cleaners!
Finally a note about water for personal washing; whilst rainwater is used for bathing and showering in many parts of the world, here in the UK where we have become accustomed to ‘purified’ water, there can be a risk associated with using rainwater for bathing. This is due to the fact that a good harvesting system will have filtration capable of removing fine particles, but this does not deal with bacteria and other micro-organisms. Whilst these are not a problem for most uses, when water is in vapour form (i.e. steam from the bath or shower) these organisms can be easily ingested.
However, where required the harvested water can be further filtered and treated to EU bathing water standards. This is generally accomplished using UV disinfection, which is safe, reliable and does not harm the water quality. Generally this system is only used where no mains water is present, as it is expensive to install and frequently it is not possible for most domestic properties to collect enough water to meet this increased demand.
The convention therefore, is to focus on using harvested water for the purposes outlined above and use mains water for all personal use.
Our FREE Guide To Rainwater Harvesting Systems
As we have seen, rainwater can be used for a wide variety of purposes. At Rainharvesting Systems we specialise in high-performance rain harvesting systems of different sizes for domestic properties in the UK. With a selection of above ground and below ground storage tanks, energy-efficient pumps and outlet systems, a rain harvesting system can add significant value to a property development, as well as long-term savings for homeowners.
For more information, please download our Rainwater Harvesting Systems Guide, a free e-book outlining all the main harvesting and storage systems, with the comparative costs and benefits of each. Click here to claim your copy today.