Frequently Asked Questions

It is simply a method of collecting rainwater from a buildings’ roof (via the normal drainage system), filtering and storing it for re-use, in order to reduce the amount of water used from the mains supply, and to reduce the amount of stormwater run-off.

We have more experience than any other UK company – as the longest running Rainwater Harvesting company, we have gained a wealth of knowledge. We only use quality components that are tried and tested, and we provide excellent technical support.

Our name says it all, and has become synonymous with the idea of rainwater harvesting.

We are also one of the few UK companies entirely focused on this technology, and we are the country’s sole distributor for Wisy AG, leading German manufactures in high quality rainwater harvesting components.

To reduce the amount of water you need to buy from your utility company and to make a difference environmentally by saving a precious resource. Imagine the difference it would make to our water reservoirs if all new homes could effectively reduce their water consumption by up to 50%! During excessive rainfall events, which are becoming much more common due to climate change, rainwater storage also alleviates stormwater runoff thus reducing the risk of flooding.

Most roof surfaces are perfectly ok to collect from. The most ideal are slate or other smooth non-absorbent materials, and most types of tile are suitable. Flat roofs will give a reduced collection rate due to puddling and higher evaporation losses. Green roofs are designed to be absorbent so will give a much reduced yield, and the water will invariably be discoloured so has limited use. Wooden roofs (shingles) can also lead to discolouration.

As long as the water is collected from a good surface, a good quality leaf filter is used, and the water is stored in a cool dark place (underground is preferable) then the water is extremely clean and should not have any colouration or smell. Keeping water clean over a long period of time will largely depend on regular filter cleaning, so ensure the system is easy to look after by choosing the right filter.

One system can provide for both domestic use and garden irrigation, and many people go for this option using the harvested water for toilets, laundry, garden and carwash. However we do also provide low-cost systems that are specifically for garden use. If you have a garden system without any back-up from the mains water supply then it will be exempt from any hosepipe restrictions.

Systems for the house and garden are normally installed when a house is being built or renovated because a separate plumbing circuit to deliver the water to the toilets is necessary.

No, not at all! We can provide both direct (no header tank) and indirect (with header tank) systems – for advice on which system is suitable for you, feel free to give us a quick call or email us, we’re more than happy to help.

A Ballpark figure of £2,300.00 ex VAT is adequate for most domestic systems. This covers the cost of the components and delivery to site. This cost does include ALL of the components you need. The system should always be sized for your needs and therefore some level of consultation is recommended before you choose a system. You also have a choice of basic systems and more professional, energy efficient systems which will affect cost.

Being an independent specialist and the UK’s longest running Rainwater Harvesting company gives us a wealth of knowledge of various systems and components available, so feel free to call us to discuss the options available to you.

The fundamentals of a rainwater system do not differ too much from supplier to supplier, however a rainwater system is a combination of components and as such quality can vary a lot between systems available. This can affect performance, ease of maintenance and longevity of individual components. Most systems are quite basic in their operation which work perfectly fine, spending a little more will often make the system easier to maintain and cheaper to run (more energy efficient).

A prime example is using an external filter over one built into the tank. It will give a significantly better water quality over time and because it isn’t located in the tank, it’s easier and safer to clean regularly.

The controls for your harvesting system can fit into the back of a standard kitchen cupboard. Alternatively they can simply be fitted to a wall in the utility room or somewhere similar; allow a space of about 50cm x 50cm.

Yes, step-by-step details are provided in an easily understood form, avoiding unnecessary technical language. These instructions are written and illustrated so that someone doing this for the first time will be able to follow them. If required, we can send these to you when you place your order. Installation instructions for underground tanks are sent with your order confirmation as well, so that your builder is aware of the groundwork involved.

We may know of installers who have worked with our systems in your area, and will endeavour to put you in touch with a reputable company. However, if not, don’t be concerned. Installation is straightforward and is designed to be as simple as possible. A competent general builder can install our equipment without difficulty – no special skills are required. A builder or groundworker installs the tank, filter unit and connecting pipework; this is very similar to installing a septic tank. A plumber or general builder would then complete the internal part of the installation.

Very little. The only routine maintenance necessary is the cleaning of the rainwater filter unit. This is a simple 5-minute task and should be done approximately every three months. The other components of our system are effectively maintenance-free, though we do advise an annual check. If desired we provide a maintenance service.

No, each system goes out with all the fittings you’ll need and detailed instructions. All fittings are of the highest quality, so you can be assured of their long term reliability. We do not however supply the internal plumbing and the pipework to connect your downpipes to the tank, as these will be specific to your site and supplied by the installer or plumber.

No, sadly not. There are at present no grants available for domestic rainwater harvesting, though the UKRMA actively lobbies for a grant-assistance scheme to be introduced to encourage more home-owners to embrace this technology. The Enhanced Capital Allowance scheme is available for businesses, which offers a tax incentive. Further details can be found at the Enhanced Capital Allowance website.

We can deliver anywhere in the UK, including offshore islands, subject to the appropriate delivery charges.

Most of our systems use submersible pumps and we prefer this for several reasons:

Firstly, pumps which are located indoors emit much more noise – a submersible located in an underground tank is effectively noiseless.

Secondly, it is much more efficient to push water than to suck it uphill.

Thirdly, all suction pumps have a limited capacity so must be located relatively close to the tank, – with a submersible pump the tank can be located much further away so gives more flexibility of layout.

The pumps we use are reliable, maintenance-free units.

No, no matter what you may be told, the water that falls on your roof is a gift from nature and as it is in your pipes on your property it cannot be deemed to belong to anyone else. We would always recommend that you are on a metered supply – that way you only pay for what you use. Every water supply company has a duty to install a meter (at their expense) at the householder’s request. All new properties in England and Wales are now fitted with water meters as a matter of course.

We provide high quality components, from the pumps we use to the filters, accessories and tanks. All our systems are designed to be easy to maintain to ensure the longest lifespan. We provide excellent technical support by phone 9-5 Monday to Friday, and most minor issues can be dealt with quickly and easily. We carry a huge stock of components so should the worst happen, we can supply replacement parts the next day. We can also liaise with your builder / plumber or arrange a visit by our engineers if required.

No, there are no regulations specific to rainwater harvesting but general building regulations and water regulations must be observed.

Put it ‘where the sun don’t shine!’ – No, we’re not being rude! The best place for your storage tank is below ground, where it is out of sight and the water will be in the best environment for storage – dark and cold, yet protected from freezing. Once installed, the tank then effectively takes up no space on site. Installing an underground tank is relatively simple but can be disruptive on existing properties. For this reason underground tanks are best suited to new-build or major renovation projects. If you do opt for an above ground tank, try to site it where it have some shelter from hot summer sunshine, or screen it with trellis, plants etc.

Ideally within about 10m of the building, but this is not critical. The shorter the distance between tank and building, the better for pump efficiency and reduced pipe runs. However, the tank should not be so close to the building that the excavation is in danger of undermining any foundations.

Yes, but it makes it more complicated to divert the water to the tank, and thought must go into how to arrange guttering and pipework to ensure it is not too unsightly. It may not be possible or practical to drain the entire roof area into the tank. Consideration must also be made towards frost protection.

The special vortex filters that we use are unique and extremely efficient and reliable, but their design does not lend itself to in-tank fitting. We believe this is a benefit as it makes the filter much more readily accessible and therefore it is more likely to be maintained properly. It is also important that the filter mesh dries out properly between uses in order to prevent the growth of algal biofilm; whilst this is not harmful, it can seriously affect the performance of the filter. Also there may be a safety issue if the tank’s lid must be removed just in order to clean the filter! Opening the tank on a regular basis also increases the opportunity for soil or other debris to get in to the tank. On some tanks the filter unit can be difficult to reach from ground level.

We would not recommend it be installed under a garage or driveway due to contamination risk from oil drips etc. Far simpler to have it in a landscaped area; the only visible part will be the access cover. This can easily be hidden by a pot or garden ornament.

No, it is generally the customers’ responsibility to ensure lifting equipment is on site to offload the tank. This is rarely a problem as there is usually a suitable machine on site for the excavation works. It is possible to arrange delivery by lorry equipped with a HIAB crane, but this will incur an extra cost.

That depends on how big a roof you are collecting rainwater from, where you live, and the level of usage in the property. We can calculate the appropriate size for your particular project, and the simplest method of doing this is to fill out our on-line quotation form. There is a common misconception that one should have a large a tank as possible; however it is very important that the tank is not too large as this can in time lead to water quality problems. You will also find that some suppliers have very limited choice of tank sizes available, so they may simply recommend what they have. We can supply tanks of any size and will always recommend the correct model for your needs.

Rainwater can be used for toilet flushing, washing clothes, watering the garden and car washing.

Yes, thousands of people already do! The design features of our system will provide water that is visually as clean as tap water. Being naturally soft, people in hard water areas will benefit from using less detergent and prolonged life of the washing machine due to reduced limescale build-up.

We do not recommend using untreated rainwater for drinking or personal bathing. Whilst our filters effectively effectively remove any debris, they are not designed to disinfect the water, so there is a potential for bacteria and other organisms to be present. It can be made safe by Ultra Violet treatment, but this is rarely practical on a domestic scale as most homes will not be able to harvest enough water to meet all of their needs anyway. So, it’s best to concentrate on the non-potable uses.

This is an important feature of any rainwater harvesting system and is a legal requirement. It is basically a physical break (gap) within the pipe which carries the mains ‘top-up’ water into the system. Its purpose is to prevent any risk of rainwater ‘back-siphoning’ through the pipework and potentially contaminating the mains water supply. As rainwater is collected directly from roofs, it is open to contamination from bird droppings etc. so must not be considered as drinking water quality. A fuller description of air gaps can be found here.

Potentially any rainwater can be contaminated, as it is collected from roofs which are used by birds, and this is one reason why our Water Regulations are so strict surrounding the use of non-potable water. Hence untreated rainwater should only be used for WCs, laundry, garden and car washing, and it is quite safe for these purposes.

An automatic mains water back-up system ensures that the system will not run dry. So if your tank gets too low, it will automatically receive a limited low-level ‘top-up’ from the mains. This will only ever raise the water level by a few centimetres, thereby leaving most of the tanks’ volume free to collect the next rainfall.

The amount of debris that reaches the soakaway will be no different to what it would be without the harvesting system, though there will be a lot less water. Most of this debris is organic matter, which rapidly decays and breaks down. However, this will gradually accumulate and begin to reduce the efficiency of the soakaway, but it would normally take several decades before it becomes ineffective.

If the site has or is surrounded by a lot of trees, then this will increase the rate at which the debris will accumulate. If this is the case and you are concerned about the volume of matter reaching the soakaway, then our Vortex filters can be fitted with an additional collection basket that collects the material which cannot pass through the filter.

If this device is used, it must be manually cleaned out regularly, and on a frequent basis during the autumn leaf-fall period.

We do not recommend this, because of the risk of contamination from animal faeces, chemicals etc. Although, if the water is only to be used for garden use, this is not a significant problem provided it is treated with caution.

Rainwater is ‘harvested’- in other words it is collected and filtered as it falls from the sky. Greywater is recycled wastewater from baths, showers etc. and is therefore far more contaminated. This means it is must go through a more complex and expensive process before it can be re-used.