Rainwater collection & storage
Expert advice from Onduline
Rainwater collection and storage from Onduline
As Onduline does not manufacture; or supply water rainwater collection and storage systems it is imperative that you contact specialist manufacturers and suppliers of these products on the specific design, installation and maintenance requirements of your
water collection system.
However, we make the following observations in order to provide basic guidance and is based on actual customer enquiries. We hope these notes assist you in assessing your water collection system requirements when used with Onduline roofing systems.
Do Onduline recommend water collected from the roof as being safe for human or animal consumption?
Not advised
No; although the rainwater water run-off from Onduline roofs is clean and presents no known health risk as such, we do not recommend its use for human or animal consumption due to the inherent risk of airborne pollutants and organic matter being introduced into the water collection and storage system.
When Onduline roofing products are first fixed production residue and associated construction debris can be present on the sheet surface, this can in some instances result in the discolouration of rainwater run-off from the Onduline sheets, accordingly the surface residue on the sheet should first be allowed to weather off by exposure to the elements before water is collected into storage.
Can the water be used for gardening horticultural purposes?
Subject to the roof
Yes; but we recommend its use only with proprietary water collection systems and subject to the roof, gutters and down pipes been cleaned periodically of leaves, tree debris and organic matter.
Can the rainwater be used for domestic water harvesting systems?
With precaution
Rainwater can also be collected as part of a professionally designed, installed and maintained domestic water harvesting system, but these should only be used in strict accordance with the manufacturer’s instructions and in compliance with all UK water authority regulations.
Why must I clean my roof, gutters and downpipes periodically of leaves and organic debris?
Organic matter will migrate from the roof
Left unchecked organic matter will migrate from the roof, gutters and down pipes into water butts; or collection tanks. This organic matter will then start the process of decomposition resulting in the water having a noticeably stale putrid smell, discolouration and cause a build-up of sediment within the rainwater storage tank.
If stored water becomes stagnant as described it also creates the real risk of bacteria growth, including in Legionellosis (Legionella) which although often found naturally in water collection systems, becomes a particular health risk if water taken from the storage tank and applied in fine water droplet sprays which can be readily absorbed into the lungs, so care should
also always be exercised in the use of water taken from water storage butts.
Product guarantee advice
Finally, it’s also a requirement under the terms of the Onduline product guarantee’s to clean the roof area periodically of leaf debris and organic matter to avoid the formation of moss on the roof surface and in gutters, which can act to reduce the effective service life of the Onduline corrugated sheets or shingles.
Do I need to cover my water butts and storage tanks?
Limit exposure to UV sunlight
Yes; not only to keep out autumn leaves and organic matter (including small birds) out of the storage tank, but more importantly exposure to UV sunlight as this will promote the growth of algae within the stored water, generally making it hazardous to use. In addition water storage tanks and butts left uncovered also make the perfect breeding ground for
mosquitoes.
You can cut and form lids around pipe inlets and make sure when not in use the stored water is fully shielded from direct sunlight.
What do you recommend for safe water collection from the rainwater run-off from my Onduline roof?
Specialist water treatments
We recommend firstly professional advice is taken in the design, installation and maintenance of your water collection system, whilst existing systems should be periodically checked and cleaned as directed, proprietary water cleansing additives are available to treat stored water from specialist suppliers and garden centres to match your exact requirements.
In summary
- Keep your roof clean: remove leaf debris and organic matter from roof, gutters and rainwater pipes
- Rainwater collection: follow the rainwater collections systems suppliers, or manufacturers installation, maintenance and cleaning instructions.
- Storage tanks: keep water butts and storage ranks covered to avoid exposure to sunlight and elements
USEFUL WEBSITES:
Environment Agency: Harvesting rainwater for domestic uses
Royal Horticultural Society information on garden water storage safety
British Horse Society: Pasture management
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