Common Agricultural Rainwater Contaminants and How You Can Get Rid of Them

agricultural rainwater contaminants

Increasing pressure on the UK’s water supply this summer has caused a growing interest in agricultural rainwater harvesting systems among farmers and horticultural businesses. However, any static water storage system brings with it the issue of hygiene management. 

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Collected rainwater is relatively clean and safe at source, but it picks up traces of pollutants and bacteria as it makes its way into harvesting systems, which can bloom into a serious contamination issue under some storage conditions. With the health of livestock and crops at stake, it’s important to be aware of the types of bacteria commonly found in rainwater and how to eliminate them.


Algae is a type of microscopic plant rather than a bacteria, but is worth discussing under the same heading, as algae is the most common type of growth affecting rainwater harvesting systems. You’ve probably noticed algae growth in ponds, river margins, and local lakes, but algae can also develop in agricultural rainwater collection tanks, with the added problem that it’s not always visible. 

While most algae are harmless, it’s best not to take any chances and risk having a toxic algae bloom in your harvested rainwater. If they come in contact with the soil, they may deprive crops of oxygen, and cause disease in livestock that drink that water. 

Bird And Animal Waste

Harvested rainwater typically comes into a tank through a roof on a barn or outbuilding, where it may come in contact with bird or rodent droppings. With this comes the risk of contamination with the C. psittaci and coliform bacteria, which can cause serious health problems in livestock and contaminate the soil.


Many different types of parasites can be drawn into rainwater as it passes through the roof into your tank or catchment system, including parasitic worms and their eggs carried in bird droppings. These parasites can cause illness among livestock unless a suitable water treatment system is employed. Additionally, some species of insect are drawn to standing water to lay their eggs, risking your tanks becoming a breeding ground for disease-bearing mosquitoes and gnats, as well as worms.  

How To Handle Rainwater To Remove Harmful Contaminants

Which method you use to treat harvested rainwater depends on what you intend to do with it. Water purification requirements are much more stringent for livestock drinking water than for irrigation or general agricultural purposes (e.g. washing agricultural plant).

Coarse filters are usually fine to treat rainwater for crop irrigation and for farm machinery cleaning. Water for livestock may need further stages of filtration, as well as UV sterilisation to remove harmful algae, bacteria, and pathogens. Regular microbiological testing is recommended to sustain the quality of the water in your storage tanks.

Choose The Right Storage Tanks

Algae and other harmful organisms need warmth and light to grow. If you collect rainwater into above-ground tanks, ensure they’re made of an opaque material and shielded from direct sunlight. 

Choose The Right Filtration System

An efficient filter is the best way to treat your water, as it ensures that it stays fresh for longer and that any pathogens and debris picked up along the way are filtered out. 

It’s best to use dedicated rainwater harvesting filters like the ones we supply at Enduramaxx, since they’re built to fit the inlets in our tanks. 

Advanced Water Purification

UV lamps are very effective at destroying smaller microorganisms and viruses that may escape your filters, as long as rainwater passes through a particulate filter first to remove larger contaminants – failing to do so may reduce the efficiency of the purification process. Some chemical agents may also be used, but these will need to be selected carefully to avoid potential harm to soil and livestock. Many farms install additional carbon filters to remove chemical residues from harvested rainwater before use.

Find Out More

At Enduramaxx, we manufacture and supply rainwater harvesting and storage equipment for agricultural and commercial purposes. Our rainwater tanks come with different types of filters to ensure the system is easy to maintain and harvested water is safe to use.

Please call 01778 562810 today for advice choosing the best storage and treatment solution for your business.

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