dirty water
Ref: W07e

Farm buildings without gutters

Water used for washing areas of the farm such as the yard or dairy often mixes with farm waste (manure or slurry for example) and is then known as ‘dirty water’. Rainwater can also become 'dirty water' if it runs over the yard picking up farm waste on the way. The harmful substances that the water now contains could drain off the yard and enter streams and rivers if it is not diverted and treated first.

The best way of tackling the problem of dirty water is to try and prevent water becoming dirty in the first place. There might be cattle yards or silos on the farm that do not have roofs and so rainwater falls into these areas and washes over whatever is contained there. By roofing these areas this could be prevented. In this way the farmer is avoiding the problem of dirty water.

There may be broken gutters or downpipes on the farm that need repairing or perhaps cannot cope with heavy rain. By making sure that these are kept in good condition clean rainwater is prevented from overflowing onto the mucky farmyard and becoming dirty. Clean rainwater can also be saved and used on the farm for washing or stock drinking. Clean water from the tap is very expensive if used in large quantities, and using natural rainwater can save money.

There are other ways in which farmers can prevent water becoming dirty. A device to separate dirty water and clean water could be installed on the farm to stop clean water becoming dirty when it reaches the farm buildings and surfaces.

Nutrient pollution in stream

A farmer could also look at the way clean water is used on the farm and whether the amount of dirty water produced could be reduced. For example clean water is used to wash animal dung (farmyard manure) from yards and barns on the farm. By using a brush to remove the dung before washing down the area the amount of clean water used could be reduced.

Dirty water is normally applied or diverted through ditches onto farmland and sometimes the nutrients (G1) in it are not fully valued. The dirty water might be a good source of fertiliser, containing potash and nitrogen (see fertilisers W07b) to help crops grow without having to buy and apply other fertiliser. This benefits the environment and saves the farmer money!