Why is Swabbing Important?

It should always be performed prior to any pressure testing is performed as otherwise air can remain in the system which can make the test invalid and also as air compresses it can make the pressure testing process highly dangerous.

Air also causes issues with chlorination as the chlorine does not contact the whole of the pipe interior, resulting in failed samples and failed connection.

Debris can enter the pipe work during construction and installation or whilst the pipes are in storage and if left within the water main this debris can cause issues down the line with both water quality and water pressure issues.

If swabbing isn’t performed then the following issues can present:

• Sediment in the water
• Discoloured water
• Taste and odour issues
• Microbiological contamination
• Reduced water pressure
• Full blockages and cut off of supply

Imagine a relatively small stone becoming wedged in a valve.  This may completely block the main and prevent water from reaching multiple customers.  The issue then needs to be located, the valve dug out and the blockage removed and then reinstated.  This comes at huge cost and yet is so easily prevented with appropriate swabbing and as such swabbing is an essential part of any mains commissioning process.