Environmental guidance for your business in Northern Ireland & Scotland

Wheel washing at construction sites

Wheel washing at construction sites

What you must do

Water from wheel washing areas can contain oil and diesel, as well as high levels of silt.

Ensure that water from wheel washing facilities and wash down areas is contained and not allowed to soak into surrounding ground. Channel the used water to a containment tank.

Water from a wheel wash can be recycled and reused.


You can dispose of the wastewater in two main ways:

  • to foul sewer with prior, written consent from your chosen water company in Scotland, or Northern Ireland Water in Northern Ireland

Trade effluent - managing liquid wastes

  • as hazardous/special waste, if it contains oil, diesel, petrol or certain chemicals.

Hazardous / special waste


Treating water from your wheel wash may make it more likely to be suitable for disposal to foul sewer. Use a settlement tank to remove solids from water. The settlement tank must be large enough to deal with the volume of water passing through it. An oil separator can be used to remove oil, petrol or diesel.

You will be able to get an idea of how contaminated the water is by looking for an oily sheen on the surface and by the colour of the water. The only way to be sure of the quality of the water is to take regular samples and have these tested at a laboratory.

Your chosen water company in Scotland, or Northern Ireland Water in Northern Ireland, may need laboratory test results that show the quality of the water you want to discharge before they can decide whether to issue consent.

Even after treatment to remove oil and suspended solids, the wastewater is unlikely to be suitable for disposal to surface waters or groundwater.

Solids that settle out from wheel wash water may also contain road salts, antifreeze and brake dirt. There is no simple method available to remove these materials from wheel wash water on site.

You should consider having any solid residues analysed before disposal as these solids may be hazardous/special waste. Your local environmental regulator or your waste haulage contractor may be able to advise you on testing facilities in your area.

SEE ALSO: GPP 13 Vehicle washing and cleaning

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